Final Exam Study Guide
Final Exam Study Guide BSC 2023
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This 58 page Study Guide was uploaded by Eleonora Sacks on Thursday April 28, 2016. The Study Guide belongs to BSC 2023 at Florida International University taught by Paul Sharp in Spring 2016. Since its upload, it has received 163 views. For similar materials see Human Biology in Biology at Florida International University.
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Date Created: 04/28/16
Exam 1 Study Guide 4/28/16 11:22 PM Living Organisms • 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. 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). • 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 • 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 thkey) • 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. • Intermembrane space: found between the two membranes • Bomb calorimeter: measures the amount of calories in food • Pathways of cellular respiration: • Glycolisis: 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 C i6to 2 pyruvates of C 3 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) 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 organellesand 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 organizingcenter. 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 damagedand 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” MEIOSIS: • 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 II MEIOSIS I • • Spermatogenesis: production of sperm. Starts off with one sperm that produces 4 viable sperm cells. Starts in puberty. <--- Oogenesis • 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 GENETICS • 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 Legend eyes, long fingers) • 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- aa) Punnet square • 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 Nervous System • 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) • Functions: 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) o Parts: § Cell body, § Dendrites § Axon o Types: § 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 • Synapse: • 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 • 1 : presynaptic membrane (axon terminal) nd • 2 : synaptic cleft • 3 : 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 • Senses: • 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 § Incus § 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 cochlea) 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 Blood: • 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. Cardiovascular system: • Organ system in which blood vessels distribute blood by the pumping action of the heart. • Parts: • 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 Digestive System: • 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) o Teeth: § Lie in sockets in the gum covered margins of the maxilla and mandible § 2 main divisions: crown and root § 32 teeth in adults § Composed of: ú Enamel: hard material composed of calcium compounds that cover the crown (the part of the tooth that is above the gum) ú Dentin: thick layer of bone-like material beneath enamel ú Pulp: inner tissue containing blood vessels and nerves § Problems: § 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 tooth • Pharynx: the back of the throat • Esophagus • Stomach • 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. • Pharynx: • 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 o Diabetes: § 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 age • 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 • Functions: • 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 • Intramem
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