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Exam 1 Study Guide 4/28/16 11:22 PM
• Basic characteristics of living organisms:
• Organized (has cells, sistems, etc)
• Ability to reproduce
• Have homeostasis
• Respond to stimuli
• Acquire and store energy and materials
• Have an evolutionary history
• Grow and develop
• Homeostasis: body equilibrium, the body’s internal environment remains constant and between physiological limits.
• Negative feedback: reduces and eliminates changes in the body, allows homeostasis. Eg: sweating when hot to get back to normal temperature. • Osmosis: diffusion of water
• Tonicity: the osmotic characteristics of a solution across a membrane. • Isotonic: a solution that has the same concentration of water and non diffused solutes on both sides of a membrane.
• Hypertonic: a solution that has high concentration of solutes and low concentration of water outside the cell.
• Hypotonic: a solution that has a low concentration of solutes and high concentration of water oustide the cell.
• Smallest unit that has life.
• There are over 200 different types of cells in the human body
• There are over 50 to 60 trillion cells in the human body.
• They are so small because they need a large surface area to volume ratio (the distance between the nucleus and the membrane has to be smaller so that materials can get to and from the nucleus faster).
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• Diffusion: when molecules go from being in a place of high concentration of them to a place where there is low concentration of them. Also how materials and nutrients get into the cell. Requires no energy (Passive transport). • Cell theory:
1. Cell: basic unit of life
2. All living things are made of cells
3. New cells only arise from pre-existing cells
• Types of cells:
• Eukaryotes: have membrane bound nucleus and organelles. Eg: animal and plant cells.
• Prokaryotes: non-membrane bound nucleus and organelles. eg: Bacteria • Parts of the cell:
• Plasma membrane: regulates what enters and leaves the cell, the boundary between outside and inside the cell. Selectively permeable. Composed of a phospholipid (has a head that is hydrophillic and a tail that is hydrophobic) bilayer, sugars and embedded proteins (some allow materials to pass through them). Named the Fluid Mosaic Model (named for the changing location and patterns of protein molecules in fluid phospholipid bilayer)
• Facilitated transport: type of passive transport that uss a plasma membrane carrier (proteins) to carry a substance into or out of a cell, going from a higher concentration to a lower one.
• Active transport: use of plasma membrane carrier to carry substance from higher to lower transportation. Requires energy (usually ATP). Eg: sodium potassium pump We also discuss several other topics like Which pr agency was one of the first to have a global presence?
• Metabolism: chemical reactions that happen in the cell
• Enzymes: proteins that speed up chemical reactions by lowering the required activation energy (the lowest amount of energy needed for it to happen) • Active site: on the surface of an enzyme, it’s where the substrate binds and the reaction occurs. Specific to each substrate (like a keyhole) • Substrate: reactant in the reaction that is controlled by enzyme. (like the key) • Mitochondria: organelle with 2 membranes responsible for cellular respiration (converts glucose into ATP)
• Cellular respiration formula:
• Parts of the mitochondria:
• Cristae: folded extensions of the inner membrane that produce ATP • Matrix: gel-like fluid inside the inner membrane that contains enzymes for breaking down glucose found between the cristae. If you want to learn more check out Do campaigns matter?
• Intermembrane space: found between the two membranes • Bomb calorimeter: measures the amount of calories in food • Pathways of cellular respiration:
o Happens in the cytoplasm.
o Doesn’t need oxygen (anaerobic)
o Produces 2 ATP
o Break down of glucose: splits a molecule of glucose C6 into 2 pyruvates of C3
o Converts 2 molecules of NAD+ (a coenzyme that carries
hydrogen and 2 electrons) into NADH.
• Citric Acid cycle/Kreb cycle:
o The pyruvates enter the mitochondria’s matrix and are broken down further and produce 2 ATP per glucose molecule
o Happens in the matrix
o Aerobic process (needs oxygen)
o NAD+ accepts hydrogen and electrons and converts to NADH • Electron transport chain:
o Happens in the inner membrane of the mitochondria
o Electrons pass through membrane-bound carrier molecules from a higher energy level to a lower energy level.
o Hydrogen is moved to the intermembrane space by active transport
o Oxygen makes the electrons go from one carrier to the next (like a parent making their child go down the slide) If you want to learn more check out What is multisystemic theory?
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o When the electrons move, energy is released, and it is used to pump the hydrogen into the intermembrane space.
o The hydrogen wants to go back to the matrix because of diffusion (it’s in a high concentration in the intermembrane space), so it passes through a protein that spins and produces ATP
o The electrons and hydrogen come from the NADH
o Produces H2O and 32 ATP
• ««Remember: ATP is like a dollar bill, NAD+ is like a giftcard without money, and NADH is like a giftcard with money for a specific time and place»» • Fermentation: anaerobic process. Allows the NADH to release its electrons and its hydrogen to pyruvate. Converts pyruvate to lactate to do this. Produces 2 ATP per glucose. Yeast produces alcohol and C02 • Endocytosis: a portion of the plasma membrane invaginates to envelop a substance or fluid. Types:
• Phagocytosis: solid particles
• Pinocytosis: fluids
• Receptor-mediated: uses membrane protein receptor to concentrate specific molecules.
• Exocytosis: vesicles in cell fuse with the plasma membrane during secretion (reverse of endocytosis) Eg: Neurotransmitters, hormones.
• • Cytoplasm: cytosol and organelles
• Cytoskeleton: mantains cell shapes, anchors organelles and allows cell movement. Composed of:
• Microtubules: long hollow protein cylinders found in the cytoplasm and in cilia and flagellas, used as tracks for organelle movement.
• Intermediate filaments: protein fibers that provide strength and support • Microfilaments: actin protein fibers that move cell and organelles (like little motors)
• Centriole: short cylinders of microtubules that divide and organize spindle fibers during mitosis and meiosis
• Centrosome: 2 centrioles that function as a microtubule organizing center. Active during cell division.
• Nucleus: houses chromosomal DNA
• Nuclear envelope: double membrane that encloses nucleus with nuclear pores
• Chromatin: diffuse threads containing DNA (DNA not in form of chromosomes)
• Nucleolus: region that produces subunits of ribosomes.
• Nucleoplasm: semifluid medium inside nucleus
• Nuclear pores: allow ribosomal subunits to exit and proteins to enter. • Ribosomes: synthesize proteins using mRNA (messenger RNA: a copy of DNA that has genetic information) template
• Endomembrane system: a series of membraneous organelles that process materials for the cell:
• Nuclear envelope
• E.R. (endoplasmatic reticulum): continuous of the nuclear envelope, has saccules and channels:
• Rough E.R.: has ribosomes embedded on the side that faces the cytoplasm. The ribosomes synthesize proteins and then the proteins enter the ER interior for processing and modifications
• Smooth E.R.: has no ribosomes. Synthesizes phospholipids. • Golgi apparatus: modifies lipids and proteins from the ER and sorts, packages and distributes molecules synthesized by cell (like the Fedex of the cell)
• Lysosomes: membraneous sacs produced by the Golgi, contain hydrolitic enzymes that break down things inside them. Can fuse with endocytic vesicles.
• Vesicles: tiny membraneous sacs
• Meiosis: cell division in sperm and ovules (only in sexual reproduction). Daughter cells receive haploid number of chromosomes in varied combinations.
• Mitosis: cell division for growth, development and repair. Daughter cells receive exact chromosomal and genetic info that parent cell has. • Cell cycle: repeating sequence of cellular events
• 1. Interphase: has 3 stages:
• a. Growth (G1): cell returns to normal phase, resumes its functions and doubles its organelles
• b. Synthesis (S): DNA replication (now a chromosome has 2 sister cromatids)
• c. Growth (G2): increase in growth and final preparations for division • 2. Mitosis
• 3. Cytokinesis: division of cytoplasm
MITOSIS AND DNA REPLICATION
• DNA (deoxyribonucleic acid): composed of two complimentary strands of nitrogenous bases (Thymine (T), Cytosine (C), Adenine (A) and Guanine (G)). Never leaves the nucleus. Has a sugar-phosphate backbone (sugar is deoxyribose) and the nitrogenous bases are like the rungs of a ladder. (always T+A, G+C)
• Centromere: part of the chromosome where the sister
chromatids attach, also where the mitotic spindle
attatches to separate them.
• Mitotic spindle: formed by centrosomes where
microtubules move chromosomes
• DNA replication: happens during S phase of the interphase. The original strand of DNA is ‘unzipped’ by enzymes and each strand is completed by a new strand with the complimentary bases of each part. (Green= old strand, yellow= new strand)
• Chareotype: shows the 23 pairs of homologous chromosomes laid out. (similar in size and colour, the pair has the same genes for hair, etc, but not the same sequence because one comes from the mother and the other from the father)
• Mitosis: daughter cells are identical to father cells
• Prophase: centrosomes form and shoot microtubules (formation of the mitotic spindle starts) and the nuclear envelope breaks down.
• Metaphase: chromosomes align in the middle of the cell and the mitotic spindle is fully formed
• Anaphase: sister chromatids are separated and pulled to opposite sides of the cell
• Telophase: mitotic spindle breaks down, nuclear envelope rebuilds • Cytokinesis: cleavage furrow allows cytoplasm to divide.
• Cancer: mutations. Sometimes during replication, enzymes make mistakes. A cancer cell cannot communicate with other cells so they continue to grow even when it is no longer needed.
• Checkpoints: if a mistake during replication happened, these checkpoints ensure that it’s taken care of. (sometimes it also fails)
• G1 and G2: apoptosis (cell death) will happen if DNA is damaged and can’t be repaired
• M: mitosis doesn’t occur if cells aren’t aligned correctly.
• Diploid: 46 chromosomes in humans, “2n”
• Haploid: 23 chromosomes in humans, “n”
• Only sex cells (sperm and eggs)
• Goal: produce haploid cell
• Meiosis 1: reductional division (homologous pairs
separate), 1 cell produces 2 haploid cells
• Prophase 1: chromosomes have duplicated, mitotic spindle starts, nuclear envelope starts to break down. Crossing over: homologous pairs synapse (‘get freaky’), where they cross or join, they exchange material, that place is called the chiasmata. Crossing over increases genetic variability.
• Metaphase 1: homologous pairs align in the middle of the cell. Independent assortment: random orientation of the homologous pairs. • Anaphase 1: whole cromosom is pulled apart (the pairs are separated) • Telophase 1: interkinesis (type of cytokinesis) occurs. Same as mitotics telophase
• Meiosis 2: sister cromatids separate, produces 4 haploid cells • Prophase 2: no crossing over (this only happens in prophase 1, meiosis 1). The nuclear envelope breaks and the spindle begins to form • Metaphase 2: the chromosome aligns in the middle
• Anaphase 2: sister cromatids are separated
• Telophase 2: same as mitotis telophase, interkinesis also takes place.
⇦MEIOSIS I⇦MEIOSIS II
• Spermatogenesis: production of
sperm. Starts off with one sperm that produces 4 viable sperm cells. Starts in puberty.
• Oogenesis: production of eggs. 1 viable egg is produced. Starts since the baby girl is in the womb. The secondary oocyte will only go through meiosis 2 if it has been fertilized by a sperm.
• Polar body: has the same genes as the oocyte
• Gene: DNA sequence found in chromosomes
• Allele: version of a gene (for the gene of hair color, there are alleles for dark hair, blond, red, etc)
• Locus: site where the gene is on the chromosome
• Genotype: genetic information responsible for a specific trait (written as Aa, BB, cc)
• Phenotype: the physical expression of a gene (blue eyes,
• The capital letter (A) means that the gene is dominant (masks the other gene), while a lowercase letter (a) means that the gene is recessive (will only express itself in the phenotype if the other gene is also recessive
• Heterozygote: two different alleles for a gene (Aa)
• Homozygote: two of the same alleles for a gene (AA, aa)
• Punnet square: the female always goes on top, the male goes downwards.
• Phenotypic ratio: proportion of dominant:recessive. eg: the ratio for the punnet square above would be 3:1.
• Dominant always masks the recessive in a heterozygote
• Principle of segregation: 2 alleles of a gene segregate during gamete formation and are rejoined at random during fertilization. (like independent assortment)
• Remember: heterozygote is a capital letter and a lowercase letter (Aa) • Incomplete dominance: happens when the heterozygote is intermediate between the 2 homozygotes. Eg: you have HH= straight hair, hh= curly hair but Hh= wavy hair. If the parents are HH and hh, all of the children will be Hh and therefore have wavy hair.
• Codominance: happens when alleles are equally expressed in the heterozygote (one doesnt mask the other) (eg: blood type)
• Multiple-allele inheritance: inheritance pattern in which there are more than 2 alleles for a particular trait. eg: blood type, because A, B, O
• Polygenic inheritance: inheritance pattern in which more than 1 gene affects a trait. eg: skin tone, height--3 genes involved in these: A,B,C
• Autosomes: any chromosomes other than the sex chromosomes • Sex chromosomes: determine the sex of an individual (XX-female,XY-male) • Sex-linked: refers to an allele that occurs on the sex chromosome but may
control a trait that has nothing to do with the sex characteristics of an individual.
• X-linked: refers to an allele located on the X chromosome.
• eg: XB- normal vision, Xb=red/green colorblind
• Pedigree: a graphical representation of matings of offspring over multiple generations for a particular trait (like a family tree that
indicates the family members' genotype and phenotype).
• How to do pedigree problems: look at each trait and do a
punnet square to find the parents' possible genotype.
4/28/16 11:22 PM
• Organ system consisting of the brain, spinal cord, and associated nerves that coordinates the other organ systems of the body
• Central nervous system:
• Brain and spinal cord
• Peripheral nervous system:
• Nerves: composed of axons and dendrites
• Divides into:
• Somatic nervous system: nerves that serve the skin, skeletal muscle and tendons, voluntary and involuntary control (reflexes)
• Autonomic nervous system: regulates the activity of cardiac of smooth muscles (many associated with gastrointestinal tract and blood vessels that control blood flow to the body), organs and glands, also involuntary control (remember: autonomic=automatic things--no control over heart beating etc). Divides into:
o Sympathetic: activities associated with emergency (fight or flight) AKA: E division (think of Emergency)
o Parasympathetic: active under normal conditions (rest and digestion) AKA: D division (think of Diaresis--production of urine)
1. Receives sensory input: senses (touch, hearing, smell, etc) eg: the smell of baking cookies is picked up by the PNS and that info is sent to the CNS
2. CNS performs information processing and integration: the CNS reviews info and stores it as memories. eg: the smell of baking cookies evokes pleasant memories of their taste
3. CNS generates an appropriate motor response: eg the smell of baking cookies makes the CNS actives the PNS to activate muscles, glands, organs (move to eat the cookies)
• Nervous tissue contains 2 types of cells:
• Neurons: nerve cells that transmit impulses between parts of the nervous system:
o Nerve signal: action potentials traveling along a neuron, conveys info o Action potential: change in electrical conditions at a neurons
membrane (like a line of dominoes, one falls and then each one keeps falling after that). Normal state: negative on the inside, positive on the
outside: Neuron communication happens through nerve signals and action potential. The inside of the axon is negative and the outside is positive when it's at rest, but when a nerve signal is happening it flips the charges of the inside and the outside.
o Refractory period: portion of axon immediately following the action potential is unable to conduct and action potential that ensures a one way direction of a signal (cell body to axon)
▪ Cell body,
▪ Sensory neurons: sensory receptors in the PNS that take the
info to the CNS
▪ Interneurons: found entirely in the CNS (work as a relay)
▪ Motor neurons: move the info from the CNS to the PNS so that the body moves
• Neuroglia: nonconducting nerve cells that support the neurons
o Schwann cells: found connected to the axons, nucleus can be seen, like insulation for the cells, conducts saltatory conduction (jumping: the info jumps between cells which is faster--100 times faster)
• Afferent: going to the spinal cord (the info of the mallot hitting the knee is going to be processed)
• Efferent: away from spinal cord (the info goes to the muscle to make it move) • Na+: sodium, starts an action potential when is rushes inside the plasma membrane causes the flip of the signs
• Membrane potential: difference in electrical change between 2 sides of a membrane. • Resting membrane potential: polarized plasma membrane (-70 mV--you are -70 negative inside compared to the outside), the net number of positively charged ions outside and the negatively charged ions inside it
• Sodium-potassium pump: membrane protein that uses ATP to pump 3 Na+ out and 2 K+ into the cell, there's always going to be a negative charge on the inside of the membrane this way. This sets things up for diffusion, because the Na+ will be in high concentration outside and will want to go inside and vice versa with the K+, when this happens, the action potential is happening.
• Orange= sodium channel, pink=potassium channel
• Potassium can sometimes leak out, this makes the inside even more negative. • What happens during action potential?
1. Conductance of a nerve signal in axons
2. All or nothing event (either works or doesn't work), self propagating 3. 1st sodium gates open resulting in depolarization (the first domino has fallen down) (once the gate opens, the sodium rushes inside the membrane because of diffusion, so the inside of the membrane will no longer be negative)
4. Next potassium gates open resulting in repolarization (lifting the domino back up) (the potassium rushes outside because of diffusion)
5. Sodium-potassium pump restores original ionic distribution
• Stimulus: activates neuron and begins action potential (causes first domino to fall) if threshold is met (-40 Mv, when the voltage changes from -70 to -40, then the sodium gate opens up), eg: pricked by a pin
• Protein channels (gates):
1. Voltage gated: opens and closes in response to voltage changes across membrane
2. Ligand gated: opens and closes when a specific chemical binds to it 3. Mechanically regulated: responds to physical distortions of the membrane surface
• The junction between neurons (empty space between axon
terminal/presynaptic membrane and cell body or dendrites/postsynaptic membrane); nerve signal can not jump synaptic cleft
• 1st: presynaptic membrane (axon terminal)
• 2nd: synaptic cleft
• 3rd: postsynaptic membrane (usually dendrite)
• Neurotransmitters: chemicals responsible for transmission across a synapse. Closer ti -40mV you will communicate, if its getting further from the -40mV, then no. The neurotransmitters get out through exocytosis. Stored in synaptic vesicles at axon terminal. Also transmits signal between:
• Nerve--- muscle
• Nerve--- organ
• Nerve--- gland
• Events at synapse:
1. Nerve signal travels along axon to an axon terminal
2. Ca2+ ion gates open and Ca2+ rushes in axon terminal
3. Ca2+ ions promote fusion of synaptic vesicles with presynaptic membrane 4. Exocytosis of neurotransmitter into synaptic cleft and diffusion occurs 5. Neurotransmitters attach to receptors on the postsynaptic membrane. Only single type of channel opens
6. Excitatory or Inhibitory synapse, depending on the neurotransmitter 7. Integration: summing up of excitatory and inhibitory signals
8. Termination of neurotransmitter effects: degraded by enzymes
9. Reuptake by presynaptic membrane
10.Diffusion out of synapse
• Neurotoxins: include numerous chemicals that poison the nerve. Ex. Novocain • Central Nervous System: where sensory information is received & motor control is initiated
• Meninges: protective membranes that cover brain and spinal cord. Eg. Meningitis infection of the meninges
• Cerebrospinal fluid: cushions and protects CNS; fills spaces between meninges. Helps maintain blood-brain barrier
• Ventricles: interconnecting chambers that produce and serve as a reservoir for cerebrospinal fluid.
1. Lateral ventricles: proximate to cerebrum
2. Third ventricle: proximate to diencephalon
3. Fourth ventricle: proximate to cerebellum (extends all the way down to the spinal cord)
• Grey matter: contains cell bodies and short, nonmyelinated fibers • White matter: contains neuron fibers that run together in bundles called tracts (the myelinated axons make it look white):
• Ascending tracts take info to the brain
• Descending tracts take info away from the brain
• Tracts cross paths just after they enter and exit the brain
• (spinal cord diagram)
• Spinal cord: extends from base of brain and proceeds inferiorly in the vertebral column, allow for communication between brain and peripheral nerves, center for thousands of reflex arcs. Has grey matter on the inside and it looks like a butterfly, white matter on the outside (opposite to brain--brain has white inside and grey outside).
• The bulb structure (dorsal root) is where the sensory information goes to brain and is ascending
• The ventral root is of motor neurons that is descending
• Brain: enlarged superior portion of the CNS located in cranial cavity of the skull • Cerebrum: largest part of brain, consists of 2 cerebral hemispheres (left and right). communicates with and coordinates the activities of the other parts of the brain
o Left hemisphere: has greater control over language and mathematical abilities, logic, analysis
o Right hemisphere: more visual-spatial skills, intuition, emotion and art and music
• Sulci: grooves that divide each hemisphere into lobes:
o Frontal lobe: motor functions, permits voluntary muscle control, enables one to think, problem solve, speak and smell
o Parietal lobe: receives info from sensory receptors in skin and taste receptors in mouth
o Occipital lobe: interprets visual input and combines it with other sensory experiences
o Temporal lobe: sensory areas for hearing and smell
• Cerebral cortex: outer layer of cerebral hemisphere, composed of grey matter, receives sensory info and controls motor activity. Accounts for sensation, voluntary movement and thought processes. Very thin layer (2-4mm) but makes up 40% of the biomass of the brain and has over 1 billion cell bodies. Enables us to perceive, communicate, remember, understand, appreciate and initiate voluntary movements (associated with consciousness).
o Higher mental functions: memory (ability to hold a thought in mind or recall events from the past) and learning (retain information)
• Diencephalon: part of the forebrain between the 2 hemispheres and midbrain. has the thalamus, 3rd ventricle and hypothalamus
• Thalamus: "gatekeeper to the cerebrum" by controlling which received sensory info are passed on to the cerebrum (filters noises you don't pick up for example)
• Hypothalamus: helps maintain homeostasis: regulates hunger, sleep, thirst, body temp, heart rate, etc and forms floor of 3rd ventricle.
• Corpus callosum: extensive bridge of nerve tracts, enables communication between left and right hemispheres
• Cerebellum: coordinates equilibrium and motor activity to produce smooth movement (looks like a tree)
• Hypothalamus: endocrine system (hormone secretion)
• Brain stem: contains midbrain pons and medulla oblongata
• Midbrain: bellow thalamus and above pons. Reflex centers for the eye muscles and tracts (closing eye/flinching/blinking)
• Pons: bellow midbrain and above medulla oblongata. Assist the medulla oblongata in regulating breathing rate. Respiratory reflexes: apneumatic (stop breathing while sleeping/doesn't allow you to hold your breath very long--cant die) and pneumotaxic (allows for normal shallow breathing). Provides linkage between upper and lower levels of the CNS.
• Medulla oblongata: posteriorest part of the brain stem. Where tracts (from Right to left) cross. Regulates heartbeat blood pressure and breathing. Reflex centers: sneezing coughing hiccupping and swallowing
• General sense: touch
• General sensory receptors:
1. Mechanoreceptors: touch pressure vibration and strech
2. Thermoreceptors: temp changes (located in hypothalamus and skin)
3. Nociceptors: pain: respond to damaging stimuli
• Skin: composed of epidermis (outermost layer), dermis (thick, has cutaneous receptors)
• Special senses: hearing vision taste smell and balance
• Sensory receptor: dendritic end organs or parts of other cell types specialized to respond to a stimulus
• Sensation: conscious perception of a stimuli
• Sensory adaptation: when we stop taking into account a sense after its been consistent after a long period of time (why we cant smell our perfume after a while even though its there)
• Chemoreceptors: respond to chemical substances (are plasma membrane receptors that bind to specific molecules) (olfatory and taste cells)
• Taste buds: sense organ containing receptors for taste. Approx 10000 in adults most in tongue. Includes supporting cells and taste cells that end with microvilli. When molecules bind to receptor proteins of microvilli, nerve signals are generated. 4 primary types of taste (saliva is needed to taste)
• Olfactory cells: located within olfactory epithelia high in the roof of the nasal cavity.10 to 20 million in adult humans. Modified neurons, each with tuft of 6 to 12 olfactory cilia. Each olfactory cell has only 1 type of several hundred possible receptor proteins
• Types of Sensory Receptors Associated with Sight:
• Photoreceptors: sensory receptor in the retina that responds to light stimuli. o Rod cells: dim-light and peripheral vision receptors; more numerous. Ubiquitous throughout the entire retina except the fovea centralis (no color vision). When rod absorbs light, rhodopsin splits into opsin and
retinal. A cascade of reactions results in ion channels closing in rod plasma membrane.
o Cone cells: operate in bright light and provide high-acuity color vision. Located primarily in the fovea centralis. Slight differences in protein opsin structure account for three different types of cones: B (blue), G (green), R (red)
• Parts of the eye:
• Retina: innermost layer of the eyeball that contains rod and cone cells • Fovea centralis: small pit where cones are densely packed (light is normally focused on the fovea)
• Optic nerve: sensory fibers from the retina that take nerve signals to the visual cortex
• Lens: capable of changing shape too focus on things in a far distance or in a small distance. When one gets older older, it starts getting more difficult for it to change shape.
• Rhodopsin: complex molecule made up of the protein opsin and the light absorbing molecule retinal
• Types of Sensory Receptors Associated with Hearing:
• Mechanoreceptors: stimulated by mechanical forces when they or adjacent tissue are deformed by touch, pressure, vibrations, and stretch. Cells that are going to respond to mechanical stimuli
• Hair cells: cell with stereocilia (long microvilli) that is sensitive to mechanical stimulation
• Mechanoreceptors for hearing and equilibrium are located in the inner ear • The Ear:
• Outer ear: functions in hearing; filled with air. The sound waves pass through here
o Pinna: the external ear flap that catches sound waves
o Auditory canal: directs sound waves to the tympanic membrane. Not the same as the auditory tube → auditory tube is much smaller than the auditory canal.
o Fine hairs and modified sweat glands that secrete earwax (cerumen) • Middle ear: functions in hearing; filled with air.
o Tympanic membrane (eardrum): vibrates to carry the wave to three small bones (ossicles)
o Ossicles: amplify sound waves x20 → smallest bones in the body. ▪ Malleus
▪ Stapes: called this because it looks like the stirrup (the thing that you put your feet on to ride a horse). It kicks on the oval window
each time it vibrates (after oval window there's the liquid of the
o Eustachian tube (auditory tube): equalizes pressure so the eardrum doesn't burst. Connects throat to the middle ear
• Inner ear: functions in hearing and balance; filled with fluid. Important for both hearing and balance
o Cochlea: converts vibrations into nerve impulses
▪ Organ of Corti: spiral organ (looks like a snail), contains hairs
that bend with vibrations or waves, this sends impulses to the
cochlear nerve that sends them to the brain. Pitch is determined
by varying wave frequencies detected by different parts of this
organ. Volume is determined by the amplitude of the wave.
o Semicircular canals: rational equilibrium, 3 canals
▪ Detects angular movement (rotational equilibrium)
▪ Depends on hair cells at the base of each canal (ampulla), they are embedded in cupula
o Vestibule: gravitational equilibrium,
▪ Utricule: hair cells that have a jelly-like membrane on top, it
swings the opposite direction of the movement. You know which
way you're going (horizontally) even if you have your eyes
closed. In a horizontal plane
▪ Saccule: in a vertical plane, helps to know if you're going up or
down, the jelly-like membrane on top of hair cells swings the
opposite direction of the movement.
• Auditory tube: equalizes pressure in the ear, connects the middle ear to the back of the throat
• How we hear:
1. Pinna catches sound waves
2. Auditory canal directs sound waves to tympanic membrane
3. Tympanic membrane vibrates and wave is carried to ossicles (little bones) 4. Stapes vibrates and strikes the membrane of the oval window
5. Vibration of oval window causes fluid waves within the cochlea
6. Pressure waves move from vestibular canal to tympanic canal crossing basilar membrane
7. Basilar membrane moves up and down, stereocilia of hair cells embedded intectorial membrane bend
8. Nerve signal begins in the cochlear nerve and travels to the brain • Round window: relieves pressure
• It's a type of connective tissue in which cells are separated by plasma
• Plasma: liquid portion (90% is water) of blood ( makes up 55% of blood)that includes nutrients, waste, salts, and proteins. Types of plasma proteins:
1. Albumins: contribute to the plasma's osmotic pressure (water pressure, like little sponges that absorb the water so that it doesn't leak out of veins), found in egg whites
2. Globulins: antibodies, hemoglobin (provide oxygen), etc (like an archer's arrows that are made of globulin, that attack any virus or pathogen) 3. Fibrinogen: forms blood clots when activated, blood clots are important so that when we cut ourselves we don't keep on bleeding forever.
• Test question: which proteins are associated with blood?
• Formed element: includes red and white blood cells and platelets, make up 45% of blood
• Platelet: aka thrombocyte, cell fragments of Megakaryocyte, involved in clotting • Functions of blood:
• Primary transport medium: carries oxygen, CO2, hormones, nutrients, etc 1. Defends against pathogens and helps seal damaged blood vessels: antibodies, phagocytes and platelets do this
2. Regulatory functions: regulates temperature, osmotic pressure, buffers to stabilize the pH 7.4
3. Red blood cells: aka RBC, erythrocyte. Contains the protein hemoglobin. Produced in red bone marrow. It looks like a pizza dough because it has a larger surface area this way
• Hemoglobin: has iron and carries oxygen. Each one contains 4 heme groups (little proteins) and each heme group can transport 1 oxygen molecule, so one hemoglobin protein carries 4 oxygen molecules. Approx. 280 million hemoglobin molecules in one red blood cell. Carbon monoxide binds more strongly to the heme than oxygen, this is bad because it leads to us not being able to breathe in situations like being in a garage with car running and door closed.
• Anemia: insufficiency in the oxygen carrying ability of blood, due to shortage of hemoglobin. Females are more likely to be anemic because of the loss of blood they experience every month in their period
• If you go to a higher place like a mountain where there's less oxygen, there's gonna be a low level of oxygen in the blood so the kidney will produce a hormone called erythropoietin that will cause stem cells to increase red blood cell production in red bone marrow so that the blood's oxygen level returns to normal (see picture below) • Clotting: process of blood coagulation, usually initiated when injury occurs
1. Blood vessel is punctured
2. Platelets congregate and form a plug
3. Platelets and damaged tissue cells release prothrombin (like scissors, super sharp) activator (this activator will "remove the safety lock on the scissors, and turn prothrombin intro thrombin) which initiates a cascade of enzymatic reactions
4. Fibrin threads form and trap red blood cells
• Blood transfusions: whole blood of just a component of blood (red blood cells, etc), introduced into the bloodstream
• Agglutination: clumping of red blood cells due to reaction of antigens on red blood cell surface and antibody in the plasma. Happens when two blood types that aren't supposed to mix, mix during a transfusion, causes the blood to become more solid instead of a liquid form.
• ABO blood typing: based on the presence or absence of 2 possible antigens (Type A antigen or type B antigen). Depending on the blood type, the rbc produces different antibodies.
• Type A: red blood cells have type A surface antigens. Plasma has anti-B antibodies that look like Y
• Type B: rbc have type B surface antigens, plasma has anti-A antibodies that look like a moon.
• Type AB: rbc have both type A and type B surface antigens, and the plasma does not have type A or type B antibodies.
• Type O: rbc have neither type A or type B surface antigens, plasma has both anti-A and anti-B antigens.
• Test question: what blood types can safely donate blood to a type O? Only a person with type O, because type O has antibodies against type A and type B. •
• When your antibodies attack your own rbc, then you have an autoimmune disease. • Rh blood groups: based on the presence of Rh factor (antigen) on rbc • Rh-: has antibodies against Rh+
• Rh+: 85% of Americans are this type
• Hemolytic disease of newborn (HDN): happens in a newborn when the mother is Rh and the father is Rh+. In a normal pregnancy no blood is mixed between mother and baby, but when the baby is coming out, things can get messy and blood can mix. So if the baby is Rh+, the blood from the mother containing Rh- will have antigens that
attack the baby's rbc.
• RhoGAM is an antibody that is administered around 7 months into the pregnancy, contains small amount of antibodies that attack the baby's rbc if they leak into the mother's blood, quickly so that the mother doesn't produce many antibodies that attack the baby, so both the baby and the mother are safe.
• Organ system in which blood vessels distribute blood by the pumping action of the heart.
• Heart: muscular organ located in the thoracic cavity. Rhythmic contractions maintain blood circulation
• Blood vessels: closed delivery system that begins and ends at the heart. • Functions:
1. Contraction of the heart generates blood pressure (moves blood)
2. Blood vessels transport blood from heart to arteries (big transport vessels, like the turnpike or the i-95), capillaries (where all the action takes place) and veins (to go back to the heart)
3. Gas exchange occurs at the capillaries (CO2 is picked up and O2 is dropped off--because the cells need the O2 for cellular respiration). Nutrients are delivered to the cells by blood, while the blood picks up their waste.
4. Heart and blood vessels regulate blood flow, according to the body's needs • It has to send blood to the kidneys for the blood to be cleansed, to the digestive system to pick up the nutrients from the food we ate, to the respiratory system to pick up the oxygen (because after taking oxygen to the cells, the blood leaves without oxygen and needs more)
• Types of blood vessels:
1. Arteries: they conduct blood away from the heart, they carry oxygenated blood (has one exception)
2. Capillaries: smallest of the blood vessels (it has to be small so that diffusion can take place), takes oxygen to the cells and exchanges it with CO2, "where all the action happens"
3. Veins: they return blood towards the heart. Always have deoxygenated blood (has only 1 exception)
• (the little dots in the purple parts are nucleuses) • Capillaries: found between veins and arteries, very small and diffusion happens very easily and quickly in them
• Smallest blood vessels
• In some cases, only one endothelial cell forms the entire circumference (they are just 1 cell thick)
• They provide for exchange of materials like gases, nutrients, etc by diffusion. • Arterial system: the arteries near the heart withstand and smooth out large pressure fluctuations, they expand and recoil as the heart beats to propel blood onward • Pulmonary Artery: exception to the rule, it carries deoxygenated blood (takes it to the lungs)
• Pulmonary vein: only vein that is oxygenated in the body
• Arterioles: small arteries,
• When the muscle fibers contract, the vessel constrict; when the muscle fibers relaxes, the vessel dilates.
• Constriction or dilation controls blood pressure
• They lead into the capillary bed
• Capillary bed: interweaving network of capillaries
• Pre-capillary sphincter: controls blood flow through a capillary bed (sends it through something like a shortcut). It's regulated by vasomotor nerve fibers and local chemical conditions.
• Arteriovenuous shunt: enables blood to pass directly from an arteriole to a venule (the shortcut mentioned above)
• Veins: same 3 layers as arteries, but less smooth muscle and connective tissue, they have thinner walls and they have valves
• Venous valves: they resemble semilunar valves in heart in structure and function, so what they do is prevent blood to go backwards. They are most abundant in veins of the limbs. They depend on our movement, if we cross our legs we smush some veins and the blood is forced to go back to the heart.
• Varicose veins: veins that have become dilated because of damaged valves. They can be influenced by: heredity, obesity, prolonged standing, pregnancy (they go away after pregnancy). Eg: hemorrhoids, they are varicose veins in the anus.
• Venules: small veins that drain blood from the capillaries.
• Heart: muscular organ located in the thoracic cavity. Like a double pump. Its rhythmic contractions maintain blood circulation. Left side is systemic (body), right is to the lungs, that blood doesn't mix. Has 4 chambers (left and right atriums and ventricles). Authorhythmicity: it beats on its own and never gets a rest.
• Myocardium: composed of cardiac muscle formed by muscle fibers tightly joined together by intercalated disks (like puzzle pieces):
o Gap junctions: aid in simultaneous contractions of cardiac fibers o Desmosomes: protein fibers that prevent overstretching of the heart • Pericardium: protective membrane that surrounds the heart and secretes pericardial fluid (a lubrication fluid that allows the heart to move freely without friction)
• Septum: wall that separates the right and left sides of the heart, so that oxygen poor blood and oxygen rich blood never mix
• Atrium: superior chambers (left and right) that receive blood
• Ventricles: inferior chambers (left and right)
• Atrioventricular valves (AV): located between the atrium and the ventricles and prevent backflow of blood into the atria when ventricles are contracting: o Tricuspid: right side of the heart
o Bicuspid: aka Mitral valve, left side
• Semilunar valves: prevent blood return into the ventricles after contraction • Heart strings (chordae tendineae): prevent the flaps of the valves from overextending, like a tight seal, prevent valves from inverting.
• Sound of the heart is called "Lub-Dub": Lub is the AV valves slamming shut, the Dub is when the semilunar valves slam shut.
• Heart murmur: a leaky AV valve, a sight swishing sound after the "Lub" • Systemic circuit: blood vessels transport oxygenated blood from left ventricle to body, deoxygenated blood returns to right atrium
• Pulmonary circuit: blood vessels that take deoxygenated blood from right vent to lungs, oxygen blood returns to left atrium
• Coronary artery: supplies blood oxygen and food to the wall of the heart (septum). If a person eats a lot of fatty foods, plaque accumulates and creates a blocked coronary artery results in a myocardial infarction. To solve this, surgeons create a bypass surgery.
• Cardiac cycle: one heart beat, composed of two parts:
• Systole: contraction
• Diastole: relaxation
• When doctors take blood pressure, they look for the first beat and the last beat after the thing around the arm is loosened and the blood starts going to the arm again. The result will show (for example): 120/80 pressure, 120 is systole and the 80 is diastole.
• Diastole is more stable, it doesn't change if we are anxious or not. • Normal blood pressure reading: below 120/below80
• Cardiac conduction system:
• SA (sinoatrial) node:
o Specialized myocardial cells in the wall of the right atrium
o Like the pacemaker of the heart, 70 beats per minute
o Initiates the heartbeat, sends the information to the heart
o If this node is damaged, you will only have 50 beats per min
• AV (atrioventricular) node: specialized mass of conducting cells located at the atrioventricular junction in the heart. If this node is damaged, you will only have 30 beats per min
• There's a space between the two nodes so that there's time between electrical impulses. So that the atria contract before the ventricles.
• Nodes create the information that makes the parts of the heart contract, like the brain sends signals to the body for it to move via neurons, the nodes are like the brain and send the signals through the atrioventricular bundle and the Purkinje fibers.
• Atrioventricular bundle: bundle of specialized fibers that conduct impulses from the AV node to the right and left ventricles. (they carry the information that the nodes send: it tells them to contract or not)
• Purkinje fibers: modified cardiac muscle fibers of the cardiac conduction system
• ECG (Electrocardiogram): recording of electrical activity associated with the heartbeat.
• P wave: atria about to contract
• QRS wave: ventricles about to contract
• T wave: ventricular muscle fiber recovery
• Ventricular fibrillation: the heart is not pumping properly.
• When this happens, the person needs to be defibrillated using the 2 shock things that are put on people's chest in movies, and the doctors say "clear". What this does is apply a strong electrical current for short time so that all heart cells discharge electricity at once.
4/28/16 11:22 PM
• Gastrointestinal tract: a continuous hollow tube extending from the mouth to the anus. AKA: alimentary tract
• It's made up of the:
• Oral cavity: the mouth
o Hard palate: bony anterior part of the roof of the mouth
o Soft palate: only muscular portion at the back roof of the mouth
o Uvula: tissue tag hanging from the soft palate
o Salivary glands: glands associated with the mouth, they secrete saliva. Saliva isn't secreted under the tongue
o Saliva: solution of water, mucus, salivary amylase, lysozyme, and bicarbonate. (salivary amylase is the first enzyme that begins the
digestion of starch--carbs)
o Tongue: occupies the floor of the mouth. Has 4 functions:
1. Grips food
2. Repositions food between teeth
3. Mixes food with saliva (because the saliva has salivary
amylase- an enzyme that starts to break down the
carbohydrates in food we eat)
4. Movements form the bolus (the mush of the food we are
chewing that goes down when we swallow)
▪ Lie in sockets in the gum covered margins of the maxilla and
▪ 2 main divisions: crown and root
▪ 32 teeth in adults
▪ Composed of:
???? Enamel: hard material composed of calcium compounds
that cover the crown (the part of the tooth that is above
???? Dentin: thick layer of bone-like material beneath enamel
???? Pulp: inner tissue containing blood vessels and nerves
▪ Dental caries (cavity): hole in the tooth that results from acids
produced by bacteria metabolizing sugar, the hole is close to the
pulp when it starts to hurt the person.
▪ Periodontitis: inflammation of the periodontal membrane that
lines tooth sockets, this causes loss of bone and loosening of
• Pharynx: the back of the throat
• Small intestine: absorbs nutrients
• Large intestine: absorbs water
• Accessory organs: the ones that aren't part of the tubing (tract) • 5 processes necessary so that the digestive process happens: 1. Ingestion: taking of food or liquid into the body through the mouth 2. Digestion: breaking down of large nutrient molecules into smaller molecules that can be absorbed
o Mechanical digestion: cutting and mastication of food, peristalsis o Chemical digestion: digestive enzymes hydrolyze macromolecules 3. Movement (mixing): food is passed from one organ to the next via peristalsis 4. Absorption: taking in of subunit molecules (like sugars, etc) by cells or membranes. Happens in the small intestine
5. Elimination: process of expelling substances from the body via defecation (pooping)
• Peristalsis: we don't have to think about our body digesting to make it happen, it happens on its own.
• Reverse peristalsis: when there's something wrong with the food and makes us vomit or expel it.
• Fancy word for throat
• Portion of the GI tract between the mouth and esophagus
• Serves as a passageway for food and also air on its way to trachea (the trachea is parallel and in front of the esophagus)
• Esophagus: muscular tube for moving swallowed food from the pharynx to stomach • Swallowing: composed of a voluntary phase and involuntary phase (reflex action): • Soft palate moves back to close off nasal passage via uvula. This is so that food doesn't get into the nasal passage.
• Epiglottis: covers the glottis, which is the opening to the larynx (voice box). The epiglottis is like a lid on the glottis, it opens up either the path to the trachea or the
esophagus. The epiglottis doesn't work when we are swallowing and laughing at the same time.
• Peristalsis: wavelike contractions that propel the bolus along the esophagus (smooth muscles in the GI tract)
• Sphincters: muscle that surrounds a tube to open or close by relaxing or contracting. • Lower gastroesophageal sphincter: marks the entrance of the esophagus to stomach. It contracts to prevent the stomach acids from going up the esophagus (although, when this happens it's called heartburn)
• Heartburn: lower gastroesophageal sphincter fails to open and allow food to go into the stomach or it fails to close and the stomach acids go up the esophagus. • Stomach: a muscular sac that mixes food with gastric juices to form chyme which enters the small intestine:
• 1L capacity, has a pH of 2 (same as a car battery)
• Stores food, doesn't absorb nutrients. It empties 2-6 hours
• Initiates digestion of proteins with enzyme pepsin
• Controls the movement of food into the small intestine
• Gastric juice: produced by gastric glands of the stomach, includes pepsin mucus and hydrochloric acid (HCl)
• The HCl destroys bad bacteria that enter in the food
• Chyme: thick semi-fluid food material that passes from stomach to the small intestine
• Pyloric sphincter: regulates chyme entry into the small intestine
• The first place that chemical digestion happens is in the mouth, then in the stomach. • Pancreatic juice joins with the bile
• Small intestine:
• Long tube-like chamber of GI tract between stomach and large intestine • Contains enzymes secreted by pancreas and enters via duct in duodenum to digest carbs, fats and proteins
• Receives bile produced by the liver and is stored by the gallbladder that is released into the duodenum. The bile breaks things down into small globules • Parts:
o Duodenum: first 10 inches of the small intestine
o Jejunum: 2nd part of the small intestine, 8 feet long
o Ileum: 3rd part of the small intestine, 12 feet long
• Nutrients are absorbed by the small intestine
• Villus: small fingerlike projections of the inner small intestine wall (mucosa) o Outer layer has cells that have microvilli (brush border)
o Blood capillaries and small lymphatic capillaries (lacteal) are present. • Lactose intolerance: inability to digest lactose because of an enzyme deficiency • People that aren't lactose intolerant are mutants, what is supposed to happen is that
the only time that people are supposed to break down lactose was when they were a baby so they could break down the mother's milk. But after a mutation, the gene that stopped the breakdown of lactose after being a baby was changed in some people so that people can breakdown lactose their whole lives.
• Accessory organs:
• Pancreas: internal organ that produces digestive enzymes, it also produces hormones insulin (helps lower sugar levels) and glucagon (helps elevate sugar levels). Produces pancreatic juice that contains:
o Pancreatic amylase: enzyme in the pancreas that digests starch to maltose
o Trypsin: protein-digesting enzyme
o Lipase: fat-digesting enzyme secreted by the pancreas
• Bile: emulsification agent that is produced by the liver and stored in the gallbladder. It splits one big globule into tiny droplets of fat that are easier to break down. • Test question: what is the enzyme responsible for breaking down proteins in the stomach? Answer: pepsin.
• Accessory organs: they don't make up the tubing of the GI tract
• Pancreas: produces pancreatic juice that has 3 important enzymes: pancreatic amylase, trypsin and lipase. The pancreatic juice is dispersed into the duodenum in the small intestine.
o Glucose is stored in the human body as glycogen
o Plants store glucose as starch
▪ Type 1: pancreas doesn't produce enough amounts of insulin
(so the glucose can't get into the cells), typically diagnosed
before 15 years of age
▪ Type 2: pancreas doesn't make enough insulin or the body's
cells are insulin resistant, typically diagnosed after 40 years of
• Liver: dark red internal organ that:
o Detoxifies blood: hepatic portal vein brings food to liver from the GI tract capillaries
o Stores glucose as glycogen, iron, vitamins A,D,E,K and B12
o Produces plasma protein and urea
o Produces bile (that is stored in the gallbladder)
o Regulates cholesterol
o Liver diseases:
▪ Jaundice: skin turns yellowish from abnormal bilirubin (bile
pigment) in blood meaning the liver is malfunctioning
▪ Hepatitis: inflammation of the liver, often caused by the Hepatitis B virus
▪ Cirrhosis: chronic irreversible injury to the liver tissue, caused by excessive alcohol consumption over long periods of time and
Hepatitis C virus.
• Large intestine: last major portion of the digestive tract that extends from the small intestine to the anus and contains:
• Cecum: the vermiform appendix is at the end of the cecum, the cecum is a blind pouch at the beginning
• Vermiform appendix: small tubular appendage that extends out from the cecum that aids in fighting infections. If the appendix is infected it is removed because the infections it fights might explode into the body
• Colon: major portion of the large intestine, consists of the ascending colon, transverse colon, descending colon and sigmoid colon
• Rectum: terminal end of the digestive tube, last 20 cm of the large intestine, stores feces
• Anus: outlet of the digestive system, where excretion occurs
• Main function: absorb water
• DOES NOT absorb nutrients, only vitamin K and B complex
The Skeletal System:
• System of protection and support
• The skeleton is composed of bones, cartilages (prevents the bones from rubbing), joints and ligaments (connect bones together)
• Skeleton starts forming when the embryo is 6 weeks old
• 206 named bones in the skeletal system
• Make up 20% of body weight
• Tendon: connects bone to muscle
• Supports the body
• Protects soft body parts (heart)
• Produces blood cells
• Stores minerals (calcium and phosphate, these are what human bones are made of) and fats (fat is stored in the middle of the bone in yellow bone marrow)
• Allows flexible body movement (along with the muscles)
• Parts of the skeleton:
• Axial skeleton: main axis, forms the long axis of the boxy and includes the bones of the skull vertebral column and the rib cage
• Appendicular skeleton: consists of bones of the limbs
• Cartilage: white flexible semi opaque connective tissue, chondrocytes (exocytosis of matrix that makes the cartilage) are the mature cell form of cartilage, has no nerves or blood vessels, it prevents bones from rubbing each other. Takes long to repair
• Ligament: band of fibrous tissue that connects bone to bone, has cells called fibroblasts
• Tendons: cord of fibrous tissue attaching muscle to bone, has cells called fibroblasts • Every week we recycle 5 to 7% of our bone mass
• Chemical composition of bones:
• Organic components: osteoblasts, osteocytes and osteoclasts. They are composed of living tissue.
o Osteoblast: they form the bone by exocytosis of matrix and they promote the deposition of calcium salts into the matrix
o Osteocytes: maintain the structure of the bone, they are mature bone cells derived from osteoblasts
o Osteoclasts: large cells that reabsorb or break down bone matrix, they assist in returning calcium and phosphate to the blood. These acts when there is a weak bone. Also these are the cells that allow the body to grab calcium from bones if it needs it
• Inorganic components: hydroxyapatites (mineral salts), largely composed of calcium phosphate.
• When we don't ingest enough calcium, the body needs it so bad that it grabs it from the bones.
• Ossification: formation of bone
• Structure of a long bone:
• Compact bone: highly organized and composed of tubular units called osteons (like coffee stirs) These have osteocytes that occupy small cavities (lacunae). Canalicuni connect lacunae to one another and to the central canal. The central canal contains small blood vessels and nerve fibers.
• Spongy bone: has an unorganized appearance. Its composed of numerous struts or thin plates (trabeculae) separated by uneven spaces, these spaces are often filled with red bone marrow
• Intramembranous ossification: flat bones that develop between sheets of embryonic fibrous connective tissue membranes e.g. skull clavicles and mandible • Endochondrial ossification: happens in long bones: arms and legs: occurs at 6 weeks into the embryo. First a cartilage model is formed, then it grows, then there's a development of primary ossification center (spongy bone) (starts to provide resources for the bone to form), then the medullary )marrow) cavity develops, then the secondary ossification center (happens after the baby is born), lastly the formation of articular cartilage and epiphyseal plate (cartilage lining). • When do our bones stop growing: Girls on average 18 and boys on average 21. • Muscle types;
1. Smooth muscle: consists of spindle shaped, nonstriated muscle cells: they are located in the walls of hollow internal organs and blood vessels, has a single nucleus in cell, involuntary muscle that is slow to react, does not fatigue easily.
2. Cardiac muscle: specialized muscle lf the heart, striated (areas of dark light dark light dark light),has 1 or 2 nuclei per cell, cardiac cells interlock at intercalated disks, involuntary muscle
3. Skeletal muscle: composed of cylindrical multinucleate cells with obvious striations, consists of muscles attached to the body's skeleton, voluntary muscle.
• Functions of Skeletal Muscle:
• Support: allows us to stand erect
• Movement of bones and other body structures
• Maintenance of constant body temp
• Movement of fluids in the cardio and lymphatic systems
• Protection of internal organs and stabilization of joints:
o Muscles pad the bones
o Muscular wall in abdominal region protect internal organs
o Muscle tendons
• How do muscles move bones?
• They work in pairs:
o Each muscle is concerned with the movement of only 1 bone
o When muscles contract they shorten
o Muscles can only pull, not push
• Origin: the end of a muscle attached to a stationary bone
• Insertion: the end of a muscle attached to a movable bone
o When muscle contracts it pulls on tendons at its insertion and the bone moves
o The nervous system stimulates an appropriate group of muscles o EG: the prime mover and synergists
• Antagonist: muscle that acts opposite another muscle (eg: bicep and triceps) photo
• Structures of muscle cells:
• Sarcolemma: plasma membrane of a muscle fiber, forms the tubules of the T system. Encases hundreds to thousands of myofibrils
• T (transverse) tubules: membranous channel that extends inward toward sarcoplasmic reticulum
• Sarcoplasmic reticulum: smooth endoplasmic reticulum of muscle cells. Surrounds myofibrils and stores calcium ions
• Myofibril: rod-like bundle of contractile filaments found in muscle cells. They are made out of repeating units called sarcomere (they lie between z lines, as seen in the picture)
• Hierarchical order of a muscle:
1. Fascicle: a bundle of muscle fibers surrounded by connective tissue 2. Muscle fibers (Myofiber): muscle cells
3. Myofibrils: contractile portion of muscle fiber (cells) that contains a linear arrangement of sarcomeres
▪ They run the entire length of the muscle (so they are as long as your bicep or triceps etc)
▪ They are composed of even smaller myofilaments
4. Myofilament: responsible for the actual contraction of muscles.
▪ Sliding filament model: muscle contraction based on the movement of actin fibers in relation to myosin filaments.
▪ Two types:
1. Actin: makes up thin filaments in myofibrils.
2. Myosin: one of the contractile proteins of muscle. Makes up
thick filaments in myofibrils. They have little arms going out of
the sides and at the end of each arm there's a myosin head, and
these are like tugging and pulling the muscle in opposite
direction to contract the muscle. Picture.
5. Sarcomeres: the smallest contractile portion of muscle that is arranged linearly within myofibril and extends from one z line to the next z line. • Neuromuscular junction:
• Where the axon of a motor neuron is attached to a muscle.
• The axon terminal communicates with the muscle through neurotransmitters. • The muscle has ligand gated channels that allow the sodium to rush in and cause the action potential to move along the muscle until it hits the sarcoplasmic reticulum which releases calcium.
• There's tropomyosin, that's like a rope that covers the myosin binding sites (what causes the myosin to grab onto the actin and contract the muscle). • Attached to the tropomyosin are troponin, and these are turned on by calcium, when this happens it lifts the tropomyosin up and allows the myosin to bind to the actin and contract the muscle.
• Rigor mortis: when a person or animal dies and the limbs stiffen out because of a chemical change in the muscles.
Immunity and Lymphatic system:
• Lymph organs: organ of lymphatic system other than lymphatic vessels
• Primary: red bone marrow and thymus gland
• Secondary: lymph nodes, spleen, tonsils, appendix and Peyer's patches • Red bone marrow: produces red blood cells, like:
• Leukocytes (allergies, especially pollen): neutrophils (phagocytosis), eosinophils and basophils (both degranulate, throw chemicals at things that shouldn't be in the body). These are like the "common people in the castle"
• Lymphocytes: B cells (mature in bone marrow and produce antibodies), T cells (mature in thymus), natural killer cells. These are like the "military, king's guard".
• Thymus: involved in the maturation of T cells, only about 5% pass autoreactivity test. Located between the trachea and the sternum superior to the heart. • Spleen: stores and filters blood; macrophages phagocytose pathogens and debris. Largest lymphatic organ
• Lymph nodes: mass of lymphatic tissue located along the course of a lymphatic vessel, macrophages phagocytose pathogens and debris.
• Tonsils: patches of lymphatic tissue, first to encounter pathogens • Peyer's patches: lymphatic tissue located within the appendix and encounters pathogens.
• Autoimmune disease: when your own body attacks itself. The thymus is responsible so that this doesn't happen.
• One of the functions of the lymphatic vessel is to pick up what the circulatory system leaks out:
• Functional system whose components attack foreign substances or prevent their entry to the body
1. Innate immunity: skin, mucous membranes. A mechanism of defense that doesn't depend on prior exposure to the invader, nonspecific (broad) (the skin protects against everything). Immediate.
a. First line of defense:
▪ Skin: layer of protection associated with the innate immunity system. Like the castle wall. Oil and sweat glands give skin surface pH of 3-5, sweat contains lysozyme (digests bacterial cell wall), normal flora
include non-pathogenic bacteria and fungi, epidermis 10-30 cells thick and dermis 15-40 times thicker.
▪ Mucous membranes:
1. Digestive tract: saliva contains lysozyme (also found in tears),
acidic environment of stomach pH of 1.5-3.5, digestive enzymes
in intestine, nonpathogenic normal flora, vomiting and diarrhea
may expel pathogens.
2. Respiratory tract: pathogens trapped by mucus in bronchi and
bronchioles, ciliated epithelial cells sweep mucus toward the
glottis, coughing and sneezing expels pathogens.
3. Urogenital tract: vaginal secretions viscous and acidic,
secretions promote growth of normal flora, acidic urine of both
sexes may wash out pathogens.
2. Adaptive (acquired) immunity: specific to the particular non-self material, requires time for development, occurs more quickly and vigorously on secondary response. • Second line of defense: phagocytes, inflammation, complement and interferon, chemical signals:
o Recognize a wide spectrum of pathogens without a need for prior exposure
o Key players include neutrophils, monocytes that become macrophages o These cells phagocytose pathogens and trigger the release of
cytokines (chemical signals, protein hormones that let other immune system "soldiers" or cells where the problem is)
o Results in inflammation and specific immune responses
o Inflammation: occurs over seconds, minutes, hours and days
▪ Histamine: chemical that dilates blood vessels
▪ Bradykinins: make the spaces that make the blood vessels
leaky even larger so there is more leakage
▪ Prostaglandins: responsible for the pain (eg: sunburnt skin pain) 1. Dilation of blood vessels increases blood flow at site (RED &
2. Increased permeability of capillaries causing edema (tissue
SWELLING). This allows the cells to move to the site of the
3. Tissue swelling puts pressure on nerve endings (PAIN and
potential loss of function)
4. Macrophages and neutrophils release cytokine tumor necrosis factor (TNF) which acts on hypothalamus to raise the body temp (fever)
5. Cell death (necrosis) always occurs to some degree during inflammation
o Complement: 30 proteins that are produced by the liver. They circulate freely in blood plasma. When activated, one forms a domino effect on another causing a cascade of events that form a membrane attack complex (MAC) that form pores in pathogens that have lipid membrane to induce lysis (causes the bad bacteria to explode by making holes in its membrane)
o Interferon: antiviral agent produced by an infected cell that blocks infection of an uninfected cell (degrades RNA and blocks protein production). It works especially with virus. Type of cytokine.
o Cytokines: protein hormones used by immune cells to communicate. Can affect same cells that produce them, cells nearby or cells distant in body. EG: interferon.
• Third line of defense: ADAPTIVE IMMUNITY
o Important aspects of the immune response:
1. Non-self recognition: ability to distinguish self-antigens from non-self
???? Antigen: foreign substance that stimulates and immune
response. EG: dust, pollen
???? Antibody: protein produced in response to the presence
of an antigen
2. Antigen-specific: recognizes and is directed against specific antigens
3. Systemic response: immunity is not restricted to initial infection site
4. "Memory": recognizes and mounts stronger attack on previously encountered pathogens.
o Major histocompatibility complex (MHC): cell surface glycoproteins, polymorphic. Think of them as flag poles on the surface of cells. Only T cells can decipher them.
▪ MHC class 1 protein: found in eukaryotes (cells that have
nucleus), has cytotoxic T cells (CD8) respond to endogenous
antigen (generated inside the cell) bound to MHC class 1 protein. The CD8 is the only cell that understands the signal. When the CD8 connects with an infected cell and realizes that something is wrong, it produces cytokines that communicate with the infected cell through its own cytokines which cause the CD8 to clone itself and attack the infected cell until it causes apoptosis (to explode)
▪ MHC class 2 protein:
???? Found only on professional antigen presenting cells like Macrophages and B cells
???? Helper T cells (CD4) respond to exogenous antigen
(comes from outside the cell) bound to MHC class 2
???? When bacteria is engulfed by macrophages, the Helper T cell connects with the macrophages, then clones itself,
and then has 2 choices: to produce a humoral response (communicates with a B cell that clones and the "general" (CD4) signals them to fire their arrows towards the
infected cell) or a cellular response (it "juices up" the
macrophage and destroys the bacteria)
o Two overlapping arms of immunity:
▪ Cell-mediated immunity: (like hand to hand combat), associated with cell surfaces, T-cell receptors that are unable to see free antigens
???? T cells: 2 main types that include CD8 (directly attack cells that carry specific antigens) and CD4 (regulate
immune responses of other cells, they are like the
"general" during battle)
• Produced in red bone marrow, they migrate to the
thymus to mature and be selected
• T cell receptors recognize antigen presented on
self MHC molecules
▪ Humoral immunity: (like archers shooting arrows), based on antibodies on cell surfaces and in body fluids (blood, lymph, etc).
???? B cells: bind to specific antigen with its antibody (B cell
receptor) and also serve as antigen presenting cell to
Helper T cells. They are produced in red bone marrow.
Immunoglobulin synthesis happens in bone marrow.
Tested for accuracy in red bone marrow as well. Types:
• Plasma B cells: are large B cells that have been
exposed to antigen, they produce and secrete
large amounts of antibodies, are short lived cells
that undergo apoptosis
• Memory B cells: are specific to the antigen
encountered, they live for a long time and can
respond quickly following a second exposure to
the same antigen.
• HIV (Human immunodeficiency virus): a retrovirus that attacks the body's immune system, causes AIDS.
• HIV mounts direct attack on TH cells by binding to CD4 proteins on cell surface • HIV kills TH cells faster than they can proliferate over time
• When CD4 and T cell numbers decline bellow 200 cells per microlitre of blood, the cell mediated immunity is lost.
• Ensures oxygen enters body while carbon dioxide leaves body
• Composed of:
• Upper respiratory tract: conditions air as it enters the body.
o Nasal cavity: air is humidified, heated. Has flaps of tissue. Has large hairs that filter air and mucus membranes that produce mucus.
Capillaries of sub-mucosa warm and moisten air. Tear (lacrimal)
glands drain into the nasal cavity (when we cry we get runny noses because the tears that don't drip out of our eyes go to our nose, this helps clean the nasal cavity.
o Pharynx: place where pathways for air and food cross. Connects nasal and oral cavities to the larynx,
▪ Tonsils: primary defense during breathing
▪ Epiglottis: covers the entrance to the larynx. Prevents food from going to the larynx. Like the doors to the larynx (they open and
▪ Uvula: tab of tissue at the back of throat it contracts when
touches by food and prevents food from going into the nasal
o Glottis: entrance to the larynx (covered by the epiglottis). Like the doorway to the larynx.
o Larynx: voice box. Cartilaginous organ between pharynx and trachea. ▪ Vocal cords: fold of tissue that vibrates to create vocal sounds]
▪ Glottis: opens air flow in the larynx
• Lower respiratory tract: allows oxygen to enter the blood and waste gases to leave blood.
o Trachea: windpipe, passage of air to bronchi. In front of the esophagus so that when we eat something big there's room for the trachea to
move and not collapse. Consists of connective tissue, smooth muscle and cartilaginous rings. Has mucosal membrane that produces mucus (from goblet cells) and is lines with cilia that push the mucus upward. o Bronchus/Bronchi (plural): passage of air to lungs
o Bronchioles: passage of air to alveoli
o Lungs: contain alveoli (air sacs lined with surfactant which reduces water tension) that carry out the gas exchange. The right lung has 3 lobes and the left one has 2 because of the cardiac notch.
o Diaphragm: skeletal muscle, functions in ventilation. What separates the abdominal cavity from the thoracic cavity. When we inhale it
pushes down because the lungs expand and when we exhale it pushes up because the lungs compress.
• The groups of alveoli are called lobules.
• The pulmonary artery takes deoxygenated blood to the capillaries of the alveoli and then the pulmonary vein takes oxygenated blood from the capillaries of the alveoli to the heart.
• Air (oxygen) gets into the capillaries that go to the alveoli by diffusion. It goes from a high concentration in the capillaries to a lower concentration inside the alveoli. • External respiration: pulmonary gas exchange. CO2 from the capillaries is exchanged for O2 by the alveoli.
• Internal respiration: systemic gas exchange by systemic tissue cells. Oxygen goes to tissue cells in organs and is exchanged for CO2 which goes into the capillaries •
• Our cells produce CO2 when they do cellular respiration and when they separate glucose molecules. This is the CO2 that will be exchanged for the O2. It's also exchanged through diffusion
• The right side of the heart pumps deoxygenated blood.
• If we didn't have a diaphragm we could not breathe
• Valsalva maneuver: forceful attempt to exhale against a closed airway, like pinching the nose shut and closing the mouth while pressing out air as if blowing a balloon. This is done to equalize air pressure.
• Spirometer: measures the volume of air that is inspired and expired by the lungs. • Total capacity of the lungs is 5800 ml.
• Tidal volume: normal, shallow breaths. They amount 5000 ml approx. • There's always some air left in the lungs because if we get rid of all of the air, then the lungs collapse. This air is called residual volume. When someone "knocks the wind out of you", you can't breathe, you lost some of the residual volume.
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• Organ system consisting of the kidneys and urinary bladder.
• Excretion: rids the body of nitrogenous waste and metabolic waste • Helps regulate the water-salt balance of the blood. It filters the blood • Urea: primary nitrogenous waste of human derived from amino acid breakdown
• Kidneys: organ of the urinary system that produces and secretes urine • Fist sized organ
• Produces hormone called calcitriol which increases blood calcium levels • Produces hormone called erythropoietin which stimulates red blood cell production
• The outer part is called the renal cortex. Appears granular
• Renal medulla: has the renal pyramids, the inside part of the kidney. • Renal pelvis: hollow chamber of the kidney that lies inside the renal medulla receives freshly prepared urine and takes it to the bladder.
• Renal artery: vessel that transports blood to be filtered from the aorta and delivers it to our body
• Renal vein: vessel that takes filtered blood away from the kidney to the inferior vena cava.
• Ureters: one of 2 tubes that take urine from the kidneys to the urinary bladder. is 25cm long and 5mm in diameter
• Urinary bladder: organ where urine is stored, approx. 800ml.
• Has small folds of mucosa that prevent backward flow to ureters. When there is backward flow, the kidneys stop working
• Internal sphincter (involuntary) and external sphincter (voluntary) • Approx. 300ml stretch receptors send the 1st nerve signal to the CNS. (when 300ml go into the bladder, it stretches and causes the internal sphincter to give way and the urine starts going down to the urethra. But there's an external sphincter that prevents it from going any further, it's the feeling we get when we need to pee but are holding it for a while.
• When the bladder gets to 800 ml, you're gonna pee your pants.
• It takes until a person is 3 or 4 years old to be able to control the external sphincter • Urethra: tubular structure that receives urine from the bladder
• Carries urine to the outside of body
• Micturition: emptying of the bladder, urination, peeing.
• Nephrons: (where the action takes place, the filtration) microscopic kidney unit that regulates blood composition by:
1. Glomerular filtration
2. Tubular reabsorption
3. Tubular secretion
• The part of the kidney where the filtration actually happens is the Nephron. • Nephron:
• Glomerulus: capillary bed, ball shaped, surrounded by the glomerulus capsule where glomerular filtration takes place. There's more leakage than other capillaries. Water, salts, uric acid, glucose and other molecules leak out and enter the proximal convoluted tubular
• Glomerulus capsule: double walled cup that surrounds the glomerulus • Peritubular capillary network: capillary network that surrounds a nephron and functions in reabsorption during urine formation. Purple tubes seen around the nephron in the picture above.
• Proximal convoluted tubule: next to the glomerular capsule. The things that got filtered out in the glomerulus but that we need like glucose and amino acids are put back into the capillaries by Tubular Reabsorption. Inside it has villi which increase surface area.
• Loop of the nephron: where we get water that got filtered out, found between the proximal and distal convoluted tubules. Water reabsorption takes place. • Distal convoluted tubule: distant to the glomerulus. The toxins and other things that didn't get filtered out of the blood are taken in by this tubule from
the capillary next to them through active transport called Tubular Secretion (only for toxins or things that should be removed from blood flow).
• Collecting duct: once anything reaches here it becomes part of the urine and will be excreted from the body in hours.
• Afferent arteriole (brings blood to the glomerulus) is much larger than the efferent arteriole(takes blood from the glomerulus to the peritubular capillary network), this puts the capillary bed under a lot of pressure which pushes the liquids to go out faster.
• Organ system that includes internal organs that secrete hormones • Endocrine gland: a ductless gland that secretes hormone(s) into the bloodstream. EG: pituitary, thyroid, adrenal, etc
• Exocrine gland: glands that have ducts through which their secretions are carried to a particular site. Eg: mucous, sweat, oil and salivary glands, the liver (secretes bile) • The pancreas is both exocrine (secretes digestive enzymes through pancreatic juice through a duct) and endocrine (secretes insulin and glucagon to the bloodstream, no duct)
• Hypothalamus: master gland because it has control over the other glands in the body
• Hormone: protein or steroid produced by a cell that affects a different cell (target organ). Only cells with receptors for a particular hormone can respond to it (like the cells have a lock that can only be accessed by a certain key which is a certain hormone). Hormones communicate through chemical signals. They leave the capillaries through leakage. Types of hormones:
• Peptide hormone:
o Hormones that are peptides, proteins or modified amino acids. o They work super fast but are not long lasting. EG: adrenaline
o They bind to receptors on the plasma membrane (not allowed inside the cell)
o 1st messenger: hormone bound to plasma membrane (doesn't enter cell)
o 2nd messenger: mediates intracellular response
o Class example: boys night, the guys need a pizza cutter so one of them calls his girlfriend to bring it to them, she does but they don't let
her come in because she is a girl and they are in a boys only night. (the girlfriend is the 1st messenger and the pizza cutter is the 2nd
• Steroid hormone:
o Hormones derived from cholesterol. EG: testosterone (puberty)
o They enter cell via plasma membrane
o Goes into the nucleus and binds to a receptor, and the receptor knows where to put it into the nitrogenous bases, as a result there's more production of mRNA of a certain gene.
o They act more slowly, but last longer
o Only produced by adrenal cortex, ovaries and testes.
o Class example: the girlfriend got mad because she wasn't allowed in. So the boyfriend has to redeem himself and organizes her a night with her friends and offers to make them a pizza from scratch.
• Pheromones: chemical signal released by an organism that affects the metabolism or influences the behavior of another individual of the same species. How animals of the same species recognize themselves (they can't talk with each other so this is how they find the right mate). Through pheromones, women can sync their menstrual cycles.
• Negative feedback: mechanism of homeostatic response in which a stimulus initiates reactions that reduce the stimulus (what the body does to maintain homeostasis) EG: body temp regulation (through sweating when hot or shaking when cold for example).
• Positive feedback: the goal is to get a job done even if it means getting out of homeostasis. The stimulus initiates reactions that lead to an increase in the stimulus. For example: lactation (when the baby is suckling, more milk is released) and child birth (when more pressure is put on the cervix, more oxytocin is released which causes more contractions that cause the vagina to dilate), blood clots, orgasms. • Hypothalamus: "master gland"
• Link between the nervous and endocrine systems.
• Regulates internal environment of the body.
• Controls secretions of the anterior pituitary, which controls secretions of the thyroid, adrenal cortex and gonads.
• Produces 2 hormones stores and secreted by the posterior pituitary: o Antidiuretic hormone (ADH): stimulates kidneys to reabsorb more water reducing urine volume. (during dehydration)
o Oxytocin: stimulates contraction of the uterus during childbirth and ejection of milk during nursing.
• Pituitary gland: connected to hypothalamus, consists of anterior and posterior pituitary. The anterior produces: (think of All Friendly Girls Like To Meet People) 1. Adrenocorticotropic hormone (ACTH): stimulates the adrenal cortex to produce cortisol
2. Follicle-stimulating hormone (FSH): stimulates ovarian follicle production in females and sperm production in males
3. Growth hormone (GH): promotes skeletal and muscular growth
4. Luteinizing hormone (LH): aids maturation of cells in the ovary, triggers ovulation. Causes interstitial cells of testes to produce testosterone. 5. Thyroid stimulating hormone (TSH): regulates secretion of thyroid hormones 6. Melanocyte-stimulating hormone (MSH): stimulates production and release of melanin (skin pigment)
7. Prolactin (PRL): stimulates breasts to produce milk.
• Thyroid Gland: endocrine gland in the neck that produces and secretes the following hormones:
• Thyroxine (T4): promotes growth and development, increases metabolic rate • Calcitonin: decreases blood calcium level
• Parathyroid glands: embedded in the posterior surface of thyroid. A total of 4 parathyroid glands. Produces and secretes:
• Parathyroid hormone: increases the blood calcium level
• Calcitriol: hormone produced by the kidneys, so that the intestines can absorb calcium easier.
• Pancreas: produces digestive enzymes and the hormones insulin and glucagon • Insulin: lowers blood glucose levels by promoting uptake by cells and converting glucose to glycogen in liver and skeletal muscles
• Glucagon: raises blood glucose level by causing the liver to break down glycogen.
• Adrenal glands: found on top of each kidney, consist of inner adrenal medulla and outer adrenal cortex
• Medulla: secretes the hormone epinephrine (adrenaline). This hormone is short term effective.
• Cortex: secretes mineralocorticoids (like aldosterone) and glucocorticoids (like cortisol). These hormones are for long term effect.
• Organ system that contains male of female organs specialized in the production of offspring
• Gonad: primary sex organs that produce gametes
• Ovary: produces eggs
• Testis: produces sperm
• Gamete: haploid sec cell, the egg or sperm which join in fertilization to join a zygote • Germ line cells: cells that are set aside from somatic cells during zygote development. These cells will eventually undergo meiosis to produce gametes • Somatic cells: any human cells except those that are destined to form gametes • The average length of the un-stimulated vagina is 3.25 inches. When stimulated, the vagina is 4.75 inches.
• Sperm can last in the female reproductive system for 4-5 days. The fertilized egg lasts 6-24 hours.
• When women are born they already possess all of the eggs that they will ever need. Once they reach puberty, a small amount of these eggs are chosen to develop further.
• Males ejaculate between 2-5ml of semen (one teaspoon)
• Vasectomy: procedure that prevents sperm from going into the urethra because the vas deferens is cut or knotted. Doctors make the most vasectomies in March because of March Madness (basketball tournament).
• Spermatogenesis: A spermatogonium undergoes mitosis and produces 2 daughter cells. One of these undergoes spermatogenesis while the other stays behind and then that's the one that will do mitosis the next time.
• Male external genitalea: external (can be seen), penis and scrotum. The average size of a penis is approx. 5.5 inches. 30% of the world, 75% in US, and 58% of newborns today are circumcised.
• Male reproductive parts:
• Penis: organ for copulation and urination. Designed to deliver sperm to the female reproductive tract
• Glans penis: enlarged tip of the penis
• Foreskin: loose skin covering penis that slides distally to form a cuff of skin around glans. This is what's removed during circumcision.
• Scrotum: pouch of skin that covers the testes. Hangs outside abdominopelvic cavity. It's 3 degrees lower than the temperature inside the body.
• Testes: paired male gonads within the scrotum that produce sperm and male sex organs. The testes are outside the body, inside the scrotum because if they were inside the body, that temperature would not be ideal for sperm production. If it gets cold outside, the scrotum pulls them closer to the body so that they receive heat. Parts:
o Seminiferous tubules: long coiled tubules contained within chambers of the testes, where sperm are produced. "Sperm factories"
o Spermatogenic cells: give rise to sperm and make up most of the epithelial wall of the seminiferous tubules. Sperm is produced everyday from puberty until death
o Interstitial cells: located in connective tissue surrounding seminiferous tubules. They produce and secrete androgens (testosterone) into
o Epididymis: coiled tubule next to the testes where sperm mature and may be stored for a short time. It serves as a final maturation center and empties into vas deferens
o Vas deferens: tube that leads from the epididymis to the urethra in makes and stores sperm up to several months.
• Accessory organs: paired seminal vesicles and bulbourethral glands and the single prostate gland. They produce the bulk of semen
• Seminal vesicles: convoluted structure attached to the vas deferens. Adds nutrients and 60% of fluid to semen
• Prostate gland: gland located around the male urethra below the urinary bladder. Adds secretions to semen that help activate sperm
• Bulbourethral glands: 2 small structures located below the prostate gland. Contributes mucus-containing fluid to semen. Neutralize traces of acidic urine in the urethra prior to ejaculation. Lubricates glans penis.
• Semen: fluid mixture that contains sperm and secretions of the male accessory reproductive glands. The pH is of 7 (basic), this is because the vagina is pH 4-5, so
the semen has this pH because it will neutralize the vagina's pH. Transport medium, nutrients and chemicals that protect and activate sperm. 2-5ml (a teaspoon) fluid containing 50-100 million sperm per ml.
• Chief phases of male sexual response:
• Erection: enlargement and stiffening of the penis allows penis to penetrate vagina
o Parasympathetic reflex is triggered during sexual arousal:
parasympathetic=relaxation of the body, so if you are stressed there's going to be a parasympathetic reflex so that you can get aroused (if you are stressed it's harder to get aroused)
o Promotes local release of nitric oxide that relaxes smooth muscle o Causes arterioles to dilate in erectile tissue
o Vascular spaces of erectile bodies fill with blood compressing veins. • Ejaculation: propulsion of semen from the male duct system, occurs when impulses provoking erection reach critical level, spinal reflex is initiated. Aka climax/orgasm: generates intense pleasure, muscle contraction, rapid heartbeat, elevated blood pressure.
o Reproductive ducts and accessory organs contract releasing contents to urethra
o Bladder sphincter muscle constricts
o Muscles of penis undergo rapid contractions to propel semen from urethra
• Female reproductive system:
o Vulva: all of the external genitals, consists of:
o Mons pubis: fatty rounded area covered with pubic hair
o Labia majora: posterior from mons pubis and consists of 2 elongated, hair covered fatty skin folds. Female equivalent of the scrotum
o Labia minora: 2 thin, fair free skin folds enclosed by the labia majora. Female equivalent of the ventral penis.
o Vestibule: area enclosed by the labia minora, has the urethra and vaginal openings
o Clitoris: small protruding structure composed largely of erectile tissue (meaning it enlarges during sexual stimulation-2 to 3 times as large) located anterior to the vestibule. Female equivalent of the glans penis.
o Prepuce of the clitoris: hooded skin fold of the clitoris formed by the junction of the labia minora folds
• Internal: consists of:
o Ovary: 2 ovaries, flank the uterus on either side, female gonad, produces eggs and the female sex hormones (estrogen and
o Uterine tubes/ fallopian tubes/ oviducts: tube that transports eggs to the uterus:
▪ They extend fro the uterus to the ovaries but are not attached to the ovaries
▪ Fimbria: finger like projections of uterine tube that sweep over
▪ When the egg bursts out of the ovary during ovulation it is swept into the oviduct by the fimbria and beating of cilia that line
▪ Egg lives from 6-24 hours unless fertilization occurs.
▪ Fertilization usually takes place in the oviduct.
Egg+sperm=zygote. A zygote is not enough to get pregnant,
successful implantation has to happen.
o Uterus (womb): hollow, thick walled organ located in the female pelvis where it receives retains and nourished a fertilized ovum.
▪ Developing embryo arrives at uterus several days after
▪ Implantation occurs when embryo embeds in prepared uterine
▪ Endometrium: mucous membrane lining the interior surface of
▪ Cervix: lower end of uterus, enters the vagina at nearly a right
o Vagina: organ that leads from the uterus to the vestibule and serves as the birth canal and organ of sexual intercourse in females.
• A pregnancy test looks for the presence of a hormone that's secreted by the zygote (this hormone tells the body to prepare for pregnancy)
• The ovarian cycle: on the 14th day into the cycle ovulation happens.
• When fertilization is unlikely (before ovulation), the mucus in the cervix is going to be very thick to form like a plug. When ovulation happens, the mucus becomes watery so it allows sperm to go through easier.
• Sexual Female Response:
• Labia minora, vaginal wall and clitoris become engorged with blood (grow 2-3 times)
• Breasts swell and nipples become erect
• Labia majora enlarge, redden, spread away from the vaginal opening • Vaginal wall releases lubricating fluid
• Mucus-secreting glands beneath the labia minora also provide lubrication. • During orgasm: blood pressure and pulse rate rises, breathing quickens, and the walls of the uterus and oviducts contract rhythmically without a refractory period (this means that women can have multiple orgasms, something males cannot have because they do have a refractory period)
• Ovarian cycle: monthly follicle changes occurring in the ovary that control the level of sex hormones in the blood and the uterine cycle, repeats every 28 days • Uterine cycle: monthly occurring changes in the characteristics of the endometrium, produced by the hormones that the ovaries produce (progesterone) • Primary oocyte: at birth a female has a lifetime supply of 700,000. They are stuck in late prophase 1 of meiosis until selected and activated after puberty • Follicles: structure in the ovary that produces a secondary oocyte and the hormones estrogen and progesterone. This secondary oocyte is stuck in metaphase 2 of meiosis until it's fertilized.
• Estrogen: female sex hormone that helps maintain sex organs and secondary sex characteristics (breast growth, hair under arms)
• Progesterone: hormone partly responsible for preparing uterus for the fertilized ovum • Secondary oocyte: product of meiosis 1, stuck in metaphase 2, is ovulated. • Oogenesis: production of an egg in females via meiosis
• Polar body: in oogenesis a non-functional product. 2 or 3 occur in meiosis. The secondary oocyte becomes an egg
• Only one usable gamete is produced by the female reproductive system • Ovulation: release of a secondary oocyte from the ovary
• If fertilization occurs, the secondary oocyte becomes an egg (ovum) • Occurs in the middle of the ovarian cycle
• Usually 1 per month
• Stimulated by LH
• Corpus luteum: yellow body that forms in the ovary from a follicle that has discharged its secondary oocyte, it secretes progesterone and some estrogen, if the egg is fertilized it remains for 3 months until placenta takes over. This is necessary during the beginning of pregnancy because the progesterone keeps the endometrium strong and thick and stops it from coming down.
• Menstruation: loss of blood and tissue from the uterus at the end of the uterine cycle. Women lose from 10-85 ml of blood. (35ml is the average)
• If two eggs were fertilized, the woman will have twins that aren't identical, for the twins to be identical there has to be only one fertilized egg that splits into two fertilized eggs.
• Human chorionic gonadotropin (hGC): hormone through which the embryo lets the woman's body know that it was fertilized and that it has to nurture it now. Pregnancy tests look for this hormone using an antibody that is directed against hGC in blood or urine, because hGC in the woman's blood 1 week after fertilization. Secreted by blastocyst, tells the corpus luteum to continue secreting progesterone and estrogen.
• Implantation: begins 6 days after ovulation, takes 1 week to complete. 50% chance of success.
• Placenta: temporary organ formed from both fetal and maternal issues • Provides nutrients and oxygen to developing fetus
• Carries away fetal metabolic waste
• Produces the hormones of pregnancy
• Umbilical cord: structure bearing arteries and veins that connect the placenta to the fetus (where the belly button is after birth)
• Gestation: period of pregnancy. About 280 days
• Menopause: ovulation and menstruation cease. Prompted by hormonal changes, usually occurs between 45-55 years old. A whole year without menstruation. • Contraceptives: medication or device used to reduce the chance of pregnancy • Birth control pills: oral contraceptive containing estrogen and progesterone, shuts down the pituitary production of LH (the one that produces ovulation) and FSH, follicle development is prevented (no ovulation). Tricks the body into thinking it's already pregnant so it does not ovulate.
• Intrauterine device: small piece of plastic or copper inserted into the uterus, alters uterine environment so fertilization does not occur.
• Diaphragm: soft rubber or latex cup that fits over cervix used with spermicidal jelly. This blocks the entrance to the vagina so that the sperm do not get in, especially when they are killed with spermicidal jelly.
• Female condom: large polyurethane tube that with a flexible ring fits onto cervix
• Male condom: latex sheath that fits over erect penis
• Contraceptive implants: uses synthetic progesterone to prevent ovulation, can remain effective for about 3 years.
• Contraceptive injection: uses progesterone and/or estrogen to disrupt the ovarian cycle. Not long term, effective for several months.
• Emergency contraceptive pills (ECPs): known as the morning after pill o Plan B (Levonorgestrel) is a way to prevent pregnancy after
o Prevents ovulation, may prevent a fertilized egg from implanting o No prescription needed if older than 16, works up to 72 hours after intercourse
o Not to be confused with mifepristone (RU486, Mideprex): "abortion pill" • Sterility: inability to reproduce (permanently)
• Vasectomy: both vas deferens are cut and sealed
• Tubal ligation: uterine tubes are cut and sealed.
Sexually Transmitted Diseases:
• Sexually transmitted disease (STD): an illness that has a significant probability of transmission by means of human behavior including but not limited to: vaginal intercourse, oral sex and anal sex. They can be viral, bacterial, fungal, protist and animal origin.
• Most effective way to prevent them: abstinence from sexual relations. Techniques to help reduce the risk of STDs include:
• Having sex only with people who have testes negative for STDs • Remaining in a mutually monogamous relationship that started free of STDs • Using barrier techniques, primarily condoms that reduce risk of STD transmission
• For sexually active people with multiple partners, getting vaccinated (although vaccines are not available for all STDs).
• Viral STDs:
▪ usually acquired by contaminated drinking water, but also
sexually by anal-oral contact.
▪ Symptoms appear 2-7 weeks after exposure, they include fatigue, fever, sore muscles, headache, nausea, weight loss,
jaundice, liver pain.
▪ Does not result in chronic infection. (Antibodies confer
protection against reinfection)
▪ There is a vaccine for it
▪ Spreads through sexual contact and by blood-borne transfusion ▪ Symptoms appear 6 weeks-6 months after exposure
▪ Symptoms similar to Hep. A and may include skin rash, diarrhea or constipation.
▪ Not efficiently transmitted sexually
▪ Most common chronic blood-borne infection in the United States ▪ Chronic (can return)
▪ Even though there's a vaccine for Hepatitis A and B, there is none for hepatitis C
• Herpes: viral STD caused by herpes simplex viruses type 1 or type 2 o Type 1: Usually causes cold sores and fever blisters
o Type 2: most genital herpes is caused by it. It can still be transmitted even though if there is no visual sign of an outbreak. Symptoms: o May occur 2 weeks after exposure, the blisters rupture leaving painful ulcers that take 5 days to 3 weeks to heal
o Blisters may be accompanied by fever, pain on urination, swollen lymph nodes in groin, copious discharge in women
o Usually 4-5 outbreaks a year
o No cure but there's medication that can reduce the outbreaks. • HPV (Human Papillomavirus): causative agent of genital warts o Warts are located on the penis and foreskin in men and near the vaginal opening in women
o Visible warts may be removed by surgery, freezing or burning with laser or acids
o Removed warts may recur
o A newborn can become infected while passing through the birth canal o Genital warts are associated with the cancer of the cervix as well as tumors of the vulva, vagina anus and penis
o There is a vaccine but it only defends against some strains of the virus, not all of them
o HPV Vaccine (Gardasil): protects against types, 6,11,16 and 18. Types 6 and 11 are associated with warts. Types 16 and 18 are associated with cancer.
• HIV (Human immunodeficiency virus): retrovirus that attacks the immune system
o Causative agent of AIDS: Acquired Immune Deficiency Syndrome o HIV infects cells of the immune system
o HIV mounts direct attack on helper T cells
o Monocytes are also infected
o HIV kills T helper cells (CD4) faster than they can proliferate over time o T cell count under 200 cells per microliter means cell-mediated immunity is lost (AIDS)
• Bacterial STDs: sexually transmitted diseases caused by bacteria • Gonorrhea: caused by the bacterium Neisseria gonorrhoeae
o Symptoms usually appear 2-5 days after infection
o Males: easy to diagnose, pain upon urination and thick, greenish yellow urethral discharge
o Infection may lead to pelvic inflammatory disease which can cause sterility in both sexes
o Can spread to internal body parts causing heart damage and arthritis o If a baby is exposed at birth an eye infection may result in blindness o 40% of all strains are now resistant to therapy
• Syphilis: involves 3 stages
o Stage 1: a hard chancre indicated site of infection, usually heals leaving little scarring
o Stage 2: victim breaks out in rash over body that does not itch, hair loss, infectious grey patches on mucous membranes, these symptoms disappear on their own
o Stage 3: lasts until the patient dies, may affect the cardiovascular system resulting in aneurysms, may affect the nervous system
resulting in psychological disturbances, large gummas appear on or within certain organs, penicillin is an effective antibiotic.
o Symptoms are usually mild or asymptomatic, especially in women
o 18 to 21 days post infection men may experience mild burning sensation upon urinating and a mucoid discharge
o Women may have vaginal discharge along with symptoms of urinary tract infection, also causes cervical ulcerations
o Can lead to pelvic inflammatory disease
• Fungal STDs:
• Candida Albicans: yeast infection
o Candida normally lives harmlessly on skin in mouth intestines and vagina when kept under control by normal bacterial flora
o When conditions in the body change to favor Candida growth, symptoms may occur. Like nylon underwear or tight clothing, taking certain antibiotics, bubble baths.
o Can also be transferred between sexual intercourse
o Symptoms in women include itching, redness and soreness around vagina vulva and anus as well as a cottage cheese like discharge o Symptoms in men include itching under foreskin or at tip of penis, discomfort when urinating, unusual cottage cheese like discharge o The antifungal drug clotrimazole commonly used
• Protozoan STDs: caused by protists
• Trichomonas vaginalis: single celled flagellated protozoan STD o Vagina most common site of infection in women
o Urethra most common site of infection in men
o Transmitted through sexual intercourse
o Symptoms occur 5 to 28 days post exposure
o Most men are asymptomatic or have slight burning upon urination or mild discharge
o Symptoms in women include frothy, yellow green vaginal discharge with strong odor called leukorrhea
• Animal STDs: caused by insect
• Phthirus pubis ("Crabs")
o Insects called crabs that are about 1.5-2 mm in diameter
o Notorious for infesting human genitals where they feed exclusively on blood
o Main symptom is intense itching in pubic hair area because of hypersensitivity to louse saliva
o Can be treated with permethrin 1% cream rinse, shaving off hair or using a fine toothed comb