Anatomy and Physiology Study guide
Anatomy and Physiology Study guide BSC2085
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This 36 page Study Guide was uploaded by Hannah Hartman on Friday September 23, 2016. The Study Guide belongs to BSC2085 at Florida State University taught by Dr. Yung Su in Fall 2016. Since its upload, it has received 61 views. For similar materials see Anatomy & Physiology 1 in biological science at Florida State University.
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Anatomy and Physiology Exam 1 Study Guide Powerpoint Notes In class given notes Things said by the professor in class/explanations not given Section 1:An Introduction To Anatomy and Physiology Classification of living things Humans are vertebrates o Segmented vertebral column Common characteristics suggest the same path in evolution o Two important principles: Structural and functional similarities among vertebrates Form determines function Homeostasis: the goal of physiological regulation and the key to survival in a changing environment Anatomy: the study of body structures (composition, location, associated structures) Egyptians: basic knowledge of blood vessels 1600 BC To prevent confusion, two organizations standardized anatomical vocabulary in publication Terminologica Anatomica ) Physiology: study of the function and cooperative functions of structures Includes: biochemistry, biology, chemistry, genetics Information from many different fields are incorporated and work together to have an overall understanding of physiological processes. An anatomist looks at the structures themselves, while the physiologist looks at the processes. Anatomy and Physiology are closely related Anatomical structure can give clues about function Physiological mechanisms can be explained only in the terms of the underlying anatomy All specific functions are performed by specific structures Anatomical classification: gross and microscopic anatomy Gross anatomy: macroscopic anatomy; examines large, visible structures o Surface anatomy (exterior features) o Regional anatomy (body areas) o Systemic anatomy (organ systems) o Clinical anatomy (medical specialties [pathological anatomy, radiographic anatomy, etc.) o Developmental anatomy (from birth to death) Microscopic: cells and molecules o Cytology: study of cells and their structures Cyt = cell o Histology: study of tissues and their structures Tissue: group of cells that perform a similar functions E.g. muscle tissues vs. muscle cells Physiological classification: Cell physiology (function on the cell) o E.g. looking at myocytes in the heart Organ physiology (function of an organ) o E.g. looking at the heart as a structure Systemic physiology (function of an organ system) o E.g. looking at the cardiovascular system Pathological physiology (effects of disease) o E.g. examining athlerosclerosis Levels of organization: Chemical/molecular level o Atoms are the smallest chemical units o Molecules are a group of atoms working together Cellular level o Cells are a group of atoms, molecules, and organelles working together. o (we will talk much more about cells later) Tissue level o Tissue: group of similar cells working together Organ level o Organ: group of different tissues working together o E.g. stomach there are many different tissues that work together to receive food, break down food, absorb some nutrients, and prepare everything to be processed later Organ system: group of organs working together o Humans have 11 organ systems Organism levelstu THE ORGAN SYSTEMS I recommend flashcards to memorize the major organs and functions! HELP VIDEO: Organ Systems. https://www.youtube.com/watch?v=dZQMjZRv16E Integumentary system largest organ system in the body o Major organs: skin, hair, sweat glands, nails Note its not just the skin! o Functions: protects against environmental hazards Helps regulate body temperature (thermal regulation homeostasis via sweating) Provides sensory information This is the majority of the body that comes in direct contact with the "outside world" Skeletal system o Major organs: bones, cartilages, associated ligaments, bone marrow o Functions: provides support and protection for other tissues Provides a frame for the muscles to attach on to Protects vital organs such as the lungs and the heart Stores calcium and other minerals Yellow bone marrow stores adipose tissue (fats) Forms blood cells (r ed bone marrow ) it can form red blood cells and white blood cells depending on determination Muscular system o Major organs: skeletal muscles and associated tendons. THIS IS ONLY SKELETAL MUSCLES. Skeletal muscles can be controlled. Smooth muscle is involuntary and NOT part of the muscular system o Functions: Provides movement Provides protection and support or other tissues E.g. Abdominal muscles help to support abdominal organs Generates heat that maintains body temperature (e.g. shivering) Nervous system o Major organs: brain spinal cord, peripheral nerves, sense organs Subdivided into the central nervous sytem and peripheral nervous system o Functions: Directs immediate responses to stimuli Coordinates or moderates activities of other organ systems Provides and interprets sensory information about external conditions. **everything below here will be covered in depth in the spring semester*** Endocrine system o Major organs: pituitary gland, thyroid gland, pancreas, adrenal glands, gonads, endocrine tissues in other systems o Functions: Directs longterm changes in the activities of other organ systems Adjusts metabolic activity and energy use by the body Controls many structural and functional changes during development Cardiovascular system o Major organs: heart, blood, blood vessels o Functions: Distributes blood cells, water and dissolved materials including nutrients, waste products, oxygen and carbon dioxide Distributes heat and assists in the control of body temperature Lymphatic system o Major organs: spleen, thymus, lymphatic vessels, lymph nodes, tonsils o Functions: supporting other systems defend against infection and disease Returns tissue fluid to the blood stream Respiratory System o Major organs: Nasal cavities sinus, larynx, trachea, bronchi, lungs, alveoli o Functions: gas exchange Delivers air to alveoli Provides oxygen to bloodstream Removes carbon dioxide from the bloodstream Produces sound for communication movement of air through vocal chords Digestive System o Primary structures: esophagus, stomach, small and large intestine, anus Accessory structures: teeth, tongue, pharynx (also part of the respiratory system!), liver gallbladder, pancreas o Function: process and digest food Absorbs and conserve water and nutrients Stores energy reserves Urinary System o Major organs: kidneys, ureters, urinary bladder, urethra o Functions: Excretes waste products from the blood Control water balance by regulating volume of urine produced Stores urine prior to voluntary elimination Regulation of blood ion concentration and pH Male Reproductive system: the reproductive system is the ONLY system you can live without o Major organs: testes, epididymides, ductus deferentia, seminal vesicles, prostate gland, penis, scrotum, urethra (shared), o Functions: Produce male sex cells (sperm), seminal fluids and hormones Sexual intercourse Female Reproductive system o Major organs: ovaries, uterine tubes, uterus, o Functions: Produce female sex cells (oocytes) and hormones Supports developing embryo from conception to delivery Provides milk to nourish newborn infant Sexual intercourse HOMEOSTASIS vital to an organism's survival all the body systems working together to maintain a stable internal environment o Systems respond to external and internal changes to function within a "normal range" (body temperature, fluid balance) Mechanisms of regulation o Autoregulation (intrinsic) occurs without any outside help (at the tissue level) Automatic response in a cell, tissue, or organ to some environmental change (Ex. Hypoxia causes cells to release vasodilators to increase blood flow and oxygen delivery to those cells) Hypoxia: low oxygen level; vasodilators: dilates blood vessels Here the tissue controls how much (blood flow, oxygen, etc.) it gets. o Extrinsic regulation parts of our homeostasis that are regulated by a different system Responses controlled by nervous and endocrine systems (Ex. Nervous and endocrine system increases heart rate to increase blood flow to all tissues) note: nervous system acts faster than endocrine system (because it uses electrical impulses as opposed to chemical messengers [hormones] in the circulatory system) but has a shorter lasting effect. The body will produce a number of hormones (endocrine) and neurotransmitters that will prepare your body for each specific situation. Homeostatic regulatory mechanism – consists of three components: Receptor :Receives the stimulus or environmental change Control (integration) Center : Processes the signal and sends instructions o Determines whether there should be a response Effector : Carries out instructions sent from the control center o Causes some sort of change to occur in the body Example of homeostatic regulation Function of the homeostatic mechanism: to return conditions to the set point (desired value) There is a sensor in a thermostat lets say it is set at 22*C. o If it gets much hot, the sensor sends a signal to the thermostat, that wil send a command to the AC to turn on, subsequently dropping the temperature. o Here the receptor will see that the temperature has dropped and send info to the thermostat, which send info to the AC to kick off. Negative and Positive Feedback The Role of Negative Feedback o The response of the effector negates the stimulus o Body is brought back into homeostasis o Normal range is achieved o Ex. Thermoregulation (sweating and shivering), osmoregulation (ion concentration in your blood), blood glucose level regulation (glucagon and insulin in the bloodstream) o In thermoregulation, our body works the same way as the thermostat mentioned earlier, with the brain being the thermostat. The Role of Positive Feedback "the snowball effect" o The response of the effector increases change of the stimulus o Body is moved away from homeostasis Normal range is lost o Used to speed up processes enhances a system Ex. Blood clotting, uterine contractions during child delivery (baby's head stimulates stretch receptors, which stimulates contraction of the uterus, etc.) o *Note: most homeostatic regulatory mechanisms involve negative feedback and NOT positive feedback mechanism. Systems Integration o Systems work together to maintain homeostasis. Homeostasis is a state of equilibrium o Opposing forces are in balance o Dynamic equilibrium — continual adaptation Physiological systems work to restore balance o Failure results in sease or death *Clinical Note: the difference between signs and symptoms. Symptoms – subjective experiences (pain, etc.), signs – objective, are observable and measureable (fever, rash) Symptoms cannot be measured how do you feel? Signs can be measured specific values/observable phenomenon **you do not need to know everything in the table, it is just a good summary of information** Anatomical Terminology: Superficial Anatomy o Locating structures on or near the body surface Anatomical Landmarks o Anatomical position: subject facing you, hands at sides, palms forward o Supine: lying down, face up supine has a U in it, so you can make a crunch and form a U with your body. In the prone position you cannot make this shape. o Prone: lying down, face down Superficial Anatomy o Anatomical regions Abdominopelvic quadrants: 4 four abdominopelvic quadrants are formed by two perpendicular lines that intersect at the navel. The terms for these quadrants or their abbreviations are most often used in clinical discussion Abdominopelvic regions: (9) location of the internal organs o Anatomical directions/orientation Reference terms based on subject We are not required to know anatomical landmarks for lecture, but it will be used in the lab. Sectional Anatomy o Planes and sections Used to visualize internal organization and structure Plane : a threedimensional axis i.e. frontal/ coronal; midsagittal/sagittal plane; transverse/horizontal plane Section: a slice parallel to a plane o Important in radiological techniques MRI (magnetic resonance imaging) uses magnetic fields and radio freq. to visualize subtle differences in structures (tumors); relatively safe Good for finding changes in structures PET (positron emission tomography) shows chemical function (physiology) and structure Physiological observation CT (computerassisted radiography) visualizes internal organs in 3 dimensions (more detailed than conventional radiography) Body Cavities Essential Functions of Body Cavities o Protect organs from accidental shock o Permit changes in size and shape of internal organs Ventral Body Cavity (Coelom) o Divided by the diaphragm Thoracic cavity – contains trachea, esophagus, heart, lungs Abdominopelvic cavity – from diaphragm to pelvis, contains digestive, reproductive, and urinary organs Serous Membranes Line body cavities and cover organs this helps to protect the organs from friction with the cavity wall. Consist ofparietal layer and visceral layer o Parietal layer — lines cavity o Visceral layer — covers organ o These layers protect from abrasion and friction this is aided by fluid. E.g. if you have a big meal, the stomach will push against the wall of the abdominal cavity, and the cavity can expand. The serous membrane allows for this expansion and movement within the cavity. o Thoracic cavity: Ventral pleural cavity: lungs Pericardial cavity: contains the heart Section 2: The Plasma Membrane, diffusion and osmosis Cell Theory Developed from Robert Hooke’s research – viewed slices of cork with light microscope. This research became the basis of the cell theory that: o Cells are the building blocks of all plants and animals o All cells come from the division of preexisting cells o Cells are the smallest units that perform all vital physiological functions o Each cell maintains homeostasis at the cellular level Two general classes of cells in the human body: Sex Cells (Germ Cells ) Reproductive cells o Male sperm o Female oocyte (a cell that develops into an eggs o The germ cells have half the genetic information in comparison to somatic cells Somatic Cells o Soma = body o All body cells except sex cells their main purpose is to perform a specific function within their system (e.g. nerve cells are designed to translate an impulse) The Parts of the cell: (a VERY brief overview) Nucleus: the brain of the cell all cells have a nucleus [except for red blood cells] Centrosomes and centrioles Cytoskeleton Plasma membrane separates from the external environment We will go over these in the next lecture The plasma membrane: Extracellular Fluid (Interstitial Fluid) A watery medium that surrounds a cell Plasma membrane cell (embrane ) separates cytoplasm from the extracellular fluid Cytoplasm – region of cell found between the plasma membrane and nuclear membrane o Cytosol = liquid component found in the cytoplasm o Intracellular structures collectively known as ganelles Four General Functions of the Plasma Membrane note: be able to identify lists like this on an exam Physical Isolation o Barrier separates inside from outside of cell Regulation of Exchange with the Environment o Ions and nutrients enter o Wastes eliminated and cellular products released Sensitivity to the Environment o Extracellular fluid composition can alter plasma membrane o Chemical signals (such as hormones) detected by plasma membrane receptors, or may move directly into the cell Structural Support o Anchors cells and tissues to each other or to extracellular matrix – stabilizes cells o Cancer cells often loose the ability to anchor themselves to a certain location in the body Plasma membrane composed of: 1 Membrane Lipids – largest component of plasma membrane. Consists of: o Phospholipid bilayer – two layers of phospholipids hydrophilic heads (polar) — toward watery environment, both sides Hydrophobic (nonpolar) fattyacid tails — inside membrane; this repels charged and polar molecules (such as water) Barrier to ions and water — soluble compounds In large numbers, phospholipids and glycolipids form micelles, with the hydrophilic heads facing the water molecules, and the phdrophobic tails on the inside of each micelle. Note: ions and H 2soluble compounds cannot move past the hydrophobic lipid tails. Allows for interior of cell to have a different composition than the extracellular environment 1 Membrane Proteins – second largest component of plasma membrane, but 55% of the weight of the membrane. o In a "sea" of lipids, we see large protein "iceburgs" o Two general classes: Integral proteins: Within the membrane. If traverses the width of the membrane, it is a ransmembrane protein Peripheral proteins: Bound to inner or outer surface of the membrane Less numerous than integral proteins Extracellular or intracellular face of the cell *Note: membrane proteins may be located at specific locations on a cell, inside layer or outside layer of plasma membrane if they are anchored, this is due to the cytoskeletal elements Function of Membrane Proteins Anchoring proteins (stabilizers): Attach to inside (cytoskeleton) or outside (extracellular protein fibers or other cells) structures Recognition proteins (identifiers) : Label cells as normal or abnormal – prevents immune system from attacking own cells o Many recognition proteins are glycoproteins Enzymes – may be integral or peripheral proteins o Catalyze reactions inside or outside of cell (depending on location of enzyme) Receptor proteins: Bind and respond to ligands (ions, hormones) to cause a change within the cell Carrier proteins: Transport specific solutes through membrane; o May or may not require energy (ATP). Ex. Glucose transporter does not + 2+ require energy, but Na and Ca transporters do o Allow for movement of material through the membrane o Examples: facilitated diffusion, active transport, etc. Channels – integral protein with a central pore; Regulate water flow and solutes through membrane; Many channels are highly specific for a specific ion o These basically just act as tunnels for water or ions. 1 Membrane Carbohydrates these can be attached to a variety of different components. Proteoglycans (a special type of glycoprotein with repeating subunits) , glycoproteins (sugars attached to proteins), and glycolipids (carbohydrates attached to lipids) o Extend outside cell membrane o Form sticky “sugar coat” ( glycocalyx ). Functions of the glycocalyx: Lubrication and Protection of plasma membrane prevents friction Anchoring and Locomotion Specificity in Binding (receptors) – functions as receptors Recognition (immune response) – identifiers that are genetically determined Diffusion and Osmosis HELP VIDEO: Membrane Proteins: https://www.youtube.com/watch?v=OOb2MipwIv8 Membrane Transport The plasma (cell) membrane is a barrier, but: o Nutrients must get in o Products and wastes must get out Permeability determines what moves in and out of a cell, and a membrane that: o Lets nothing in or out is mpermeable o Lets anything pass is freely permeable o Restricts movement is selectively permeable Plasma membrane is selectively permeable o Allows some materials to move freely o Restricts other materials o This selective permeability helps maintain the cell's natural state, including the ion concentrations, electrical gradients, nutrients that enter, etc. Selective permeability restricts materials based on: o Size, electrical charge, molecular shape and lipid solubility – correlation between drug potency and lipid solubility (ex. Anesthetics such as chloroform, ether). Transport through a plasma membrane can be: o Active (requiring energy ATP) all energy molecules (sugars, glucose, etc.) are broken down to create ATP. Even amino acids can be used to create ATP! o Passive (no energy required) items go into the cell or out of the cell without utilizing energy Usually this follows the rules of diffusion (net flow from high concentration to low concentration) Types of transport: o Diffusion (passive) does not use energy o Carriermediated transport (passive or active) These use carrier proteins that have various conformations. If it is going down a concentration gradient, no energy is required (facilitated diffusion passive) If it is going up its concentration gradient, you have to use ATP (active transport ) o vesicular transport (active) This is transport through the use of vesicles through ndocytosis . This requires energy. Diffusion HELP VIDEO: diffusion: https://www.youtube.com/watch?v=a_Y9wBQ610o All molecules are constantly in motion. These molecules are constantly colliding with one another. Molecules in solution move randomly until concentrations throughout the area is, on average, equal (net flow to the area of lower concentration) Random motion causes mixing, and movement towards equilibrium concentration throughout. Concentration is the amount of solute (dissolved substance) in a solvent (liquid component) Concentration gradient: The difference between the solute at one area compared to another area – creates a gradient (potential energy) o Utilization of potential energy from a concentration gradient is important for the generation of ATP. The electron transport chain generates a proton gradient, which is pumped through ATPases. o Note: during diffusion of multiple substances, treat the diffusion of each substance as if it was the only substance present. Factors Influencing Diffusion 1 Distance the particle has to move shorter distance, the greater the rate of diffusion. 2 Molecule Size: Smaller is faster 3 Temperature: More heat, faster motion more kinetic energy in the molecules, more collisions between molecules and more movement 4 Concentration gradient: The difference between high and low concentrations – greater the difference, the faster the diffusion 5 Electrical forces : Opposites attract, like charges repel. Diffusion across Plasma Membranes o Can be simple or channel mediated Materials that diffuse through plasma membrane by simple diffusion include: Lipidsoluble compounds (alcohols, fatty acids, and steroids) E.g. hormones Dissolved gases (oxygen and carbon dioxide) o Channelmediated diffusion uses a channel to transport: Watersoluble compounds and ions o Factors in channelmediated diffusion Size it needs to be pretty small Charge generally higher rate of diffusion with charge Interaction with the channel — leak channels *Note: passive channels are always open and will allow for the movement of ions in either direction. The net flow of those ions is from an area of higher concentration to an area of lower concentration (down its concentration gradient) Osmosis: A Special Case of Diffusion Osmosis is the diffusion of water across the cell membrane. Factors that affect osmosis. o More solute molecules, lower concentration of water molecules o Membrane must be freely permeable to water, selectively permeable to solutes o Water molecules diffuse across membrane toward solution with more solutes o Volume increases on the side with more solutes Water moves to that side and “dilutes” that side to make it closer in solute concentration as the other side We move from an area of higher concentration of water, to an area of lower concentration of water. THIS IS COUNTERINTUITIVE TO NORMAL DIFFUSION. Note: applied force to counter the increase in H2O volume (osmotic pressure) on the opposite side is called the hydrostatic pressure. Hydrostatic pressure: water pressure this equals the osmotic pressure (the pressure of the solute pulling on the water to move to the other side). Osmolarity and Tonicity The osmotic effect of a solute on a cell o Two fluids may have equal osmolarity (total solute concentration), but different tonicity (effect of the osmotic solution on the cells) What if we put a human cell into pure water? It would swell and burst. It will be hypertonic. Isotonic (iso = same, tonos = tension) o A solution that does not cause osmotic flow of water in or out of a cell Hypotonic (hypo = below) o Has less solutes and loses water through osmosis Hypertonic (hyper = above) o Has more solutes and gains water by osmosis A cell in a hypotonic solution: o Gains water o Ruptures ( hemolysis of red blood cells) if left unchecked A cell in a hypertonic solution: o Loses water o Shrinks (crenation of red blood cells) Note: a person suffering from severe blood loss is treated with a 0.9% solution of NaCl that is isotonic to body cells. An alternative treatment include the addition of dextran (cannot cross membranes) to increase blood volume and pressure by causing osmosis of H O fr2m tissue into blood. This is known as physiological tonicity. Carriers and Vesicles Carriermediated transport moves ions and organic substrates o Characteristics include: Specificity one transport protein, one set of substrates Saturation limits rate depends on transport proteins, not substrate Regulation cofactors such as hormones. o Cotransport (also known as symport ) Two substances move in the same direction at the same time o Countertransport: one substance moves in while another moves out o If a carriermediated transport does not use energy, it carries out: Facilitated diffusion: carrier proteins transport molecules oo large to fit through channe proteins (glucose, amino acids) Molecules bind to receptor site on carrier protein Receptor site is specific for certain molecules Protein changes shape, molecule passes through Note: this is a passive process! This net movement of material is from an area of higher concentration to an area of lower concentration. If the carriermediated transport uses energy (such as ATP), it is: Active transport (primary or secondary) Active transport proteins: move substrates against the concentration gradient Types of primary active transporters: + + 2+ 2+ Ion pumps move ions (Na , K , Ca , Mg ). Movement creates an ion gradient The sodium potassium exchange pump is an extremely important pump in the human body (e.g. neuronal function Exchange pump countertransports two ions at the same time (Na /K pump uses 1 ATP for energy to move 3 Na out of a cell and 2 K in. This concentrates those ions in their respective areas) NOTE: These are not symports, due to the use of energy (active transport) Secondary active transport: No net energy is expended by the cell. The energy used is generated from another subsequent pump. Na concentration gradient produced by the Na /K primary + active transporter creates a Na gradient (potential energy) that drives glucose transport As Na flows back in, it brings glucose with it (against glucose’s concentration gradient) ATP energy used to maintain Na gradient by pumping Na + back out Carriers and vesicles: Vesicular Transport (Bulk Transport) o Materials move into or out of cell in vesicles o Endocytosis (endo = inside) is active transport using ATP. Types of endocytosis include: Receptormediated endocytosis highly selective, must bind to receptor Receptors (glycoproteins) bind target molecules ( ligands ) Coated vesicle (endosome) carries ligands and receptors into the cell to fuse with a lysosome. Fusion causes release of ligands into the cytoplasm of cell Pinocytosis not selective (no receptors involved) Endosomes “drink” extracellular fluid Phagocytosis performed by specialized cells such as macrophages Pseudopodia ( pseudo = falsepod = foot) Fusion of pseudopodia membrane engulfs large objects into phagosome. Exocytosis (exo = outside) Granules or droplets are released from the cell Essentially the reverse of endocytosis Section 3: The Cell and Organelles HELP VIDEO: Cell overview and cell organelles: https://www.youtube.com/watch? v=URUJD5NEXC8 Organelles and the Cytoplasm Cytoplasm o All materials inside the cell and outside the nucleus o Cytosol ( intracellular ul id) Dissolved materials Nutrients, ions, gases, proteins, and waste products o High potassium (K ) and low sodium (Na ) found in cytosol (concentration difference is important for nerve cells to send electrical signals) o High protein (includes enzymes, structural proteins, etc.) o High carbohydrate/low amino acid and fat Organelles o Structures with specific function. The Organelles can be divided into: 1 Nonmembranous organelles No membrane o Direct contact with cytosol o Include the cytoskeleton microvilli centrioles cilia ribosomes , and proteasomes (do not confuse proteasomes with peroxisomes!) 2 Membranous organelles Covered with plasma membrane o Isolated from cytosol o Include the endoplasmic reticulum ER the Golgi apparatus lysosomes , peroxisomes , and mitochondria Nonmembranous Organelles 1 The Cytoskeleton o Structural proteins for shape and strength Microfilaments — thin filaments composed of the protein actin P rovides additional mechanical strength Anchors cytoskeleton to integral membrane proteins Interact with proteins for consistency of cytosol It forms a dense network = gelatinous cytosol If it is widelydispersed = fluid cytosol Pair with thick filaments ofmyosin for muscle movement (interactions causes muscle contraction) Note: myosin proteins form thick filaments in muscle tissue Intermediate filaments — midsized between microfilaments and thick filaments. Keratin fibers in superficial layers of skin are intermediate filaments. Durable (most durable of the cytoskeletal elements) Strengthen cell and maintain shape Stabilize organelles Stabilize cell position with repect to surrounding cells Microtubules — large, hollow tubes of tubulin protein Attach to centrosome located close to the nucleus (microtubule organizing center) Strengthen cell and anchor organelles Change cell shape Move vesicles within cell (kinesin and dynein – motor proteins that use ATP to move vesicles along microtubules; these proteins use the microtubules as "roadways" to move around the cell) Form spindle apparatus (moves chromosomes to opposite ends of the cell during aphase of cell division) 1 Microvilli – core composed of microfilaments o Increase plasma membrane surface area for absorption o Attach to cytoskeleton 2 Centrioles in the ntrosome (heart of the cytoskeleton) – composed of microtubules o Centrioles form spindle apparatus during cell division o Centrosome: cytoplasm surrounding centriole microtubule radiate outward to cytoplasm from here. 2 Cilia – composed of microtubules o Cilia has a ring like structure, similar to centrioles. Do not confuse this with microvilli! This allow for movement of the extension (allowing for a fluttering motion) Small hairlike extensions o Cilia move fluids across the cell surface of respiratory and reproductive systems 1 Ribosomes – used in ranslation (synthesis of polypeptides from instructions found on mRNA) o Uses mRNA as a template to create polypeptides o Two types Free ribosomes in cytoplasm Manufacture proteins for use inside the cell Fixed ribosomes attached to ER Manufacture proteins for secretion or for plasma membrane Note: fixed ribosomes start off as free ribosomes. The ribosome attaches to an mRNA strand, and as it produces the polypeptide, the specific sequence tells the ribosome to attach to the ER. 2 Proteasomes (don’t confuse with peroxisomes!) o Contain proteindigesting enzymes ( proteases ) o Disassemble damaged or viral proteins for recycling Membranous Organelles – surrounded by a phospholipid membrane, isolates organelle from cytosol All membranous organelles (except for the mitochondria and peroxisomes) are either interconnected or in communication through the movement of vesicles Membrane flow – continuous exchange of membrane parts (via vesicles) o Dynamic – allows adaptation and change o Very active in secreting cells (area equal to entire membrane surface may be replaced each hour) 1 Endoplasmic Reticulum ER ( ) Endo = within, plasm = cytoplasm, reticulum = network Cisternae (hollow tubes, flattened sheets, and chambers) are storage chambers within membranes General functions: a. Synthesis of proteins, carbohydrates, and lipids b. Storage of synthesized molecules and absorbed materials (ex. Ca2+ in muscle cells) c. Transport of materials within the ER d. Detoxification (by enzymes inside the ER) of drugs or toxins absorbed into ER i. This is common in liver cells. Two types of endoplasmic reticulum 1 Smooth endoplasmic reticulum (SER) i. No ribosomes attached ii. Synthesizes lipids and carbohydrates Phospholipids and cholesterol (for maintenance and growth of membranes) Steroid hormones (reproductive system) androgens and estrogens Glycerides (storage in liver and fat cells) Glycogen (storage in muscles) Rough endoplasmic reticulum (RER) i. Surface covered with ribosomes ii. Active in protein and glycoprotein synthesis iii. Folds polypeptide protein structures iv. Encloses products in transport vesicles Transport vesicles then deliver contents to the golgi apparatus v. Note: amount of ER and proportion of RER to SER vary with cell type. Ex. Pancreatic cells that produce digestive enzymes have extensive RER and less SER. Cells in reproductive organs that produce steroids have extensive SER and less RER. 1 Golgi Apparatus this is not technically linked to the ER, but they are linked in that they regulate and come in contact with similar products. o Vesicles enter forming (“cis”) face and exit maturing (“trans”) face Vesicles enter from the ER to the cis face and after leaving the trans face move to lysosomes, the plasma membrane, etc. o Functions Modifies and packages secretions Hormones or enzymes Substances are released by exocytosis Renews or modifies the plasma membrane (vesicles released merge with the plasma membrane to alter it) Packages special enzymes within vesicles for use in the cytoplasm (ex lysosomes) 2 Lysosomes these are connected to the ER and golgi because the proteins produced in the ER and sent to the golgi then interact with the lysosomes. These can be linked by a plasma membrane or have a "membrane flow" o Powerful enzymecontaining vesicles ( Lyso = dissolve,soma = body) o Used to break down & recycle large organic molecules and organelles o Primary lysosome Formed by Golgi apparatus and inactive enzymes Fusion of primary lysosome to endosome (transport vesicle) or damaged organelle forms: Secondary lysosome Digestive enzymes activated to break down substances, isolate toxic chemicals Note cytosol reabsorbs released nutrients from break down, remaining material expelled from cell o Lysosomes – function usually tightly controlled Functions Clean up inside cells Breaks down large molecules Attack invading bacteria Recycle damaged organelles Autolysis Auto = self,lysis= break Lysosomes membrane in damaged/dead cells break down, releasing stored enzymes (become active in cytoplasm) which destroys intracellular proteins/organelles Lysosomal storage disease – more than 30 diseases affecting children Lack of specific lysosomal enzyme causes waste product build up. ex. TaySachs disease rare disease caused by build up of lipids in brain cells. Infantile form leads to death of the individual (usually by age 4). Lysosome activation: A primary lysosome fuses with the membrane of another organelle such as a mitochondrian A primary lysosome fuses with an endosome containing fluid or solid material from outside the cell The lysosomal membrane breaks down during autolysis following injury to, or death of, the cell 2 Peroxisomes – enzymecontaining vesicles (smaller than lysosomes and contains different enzymes) o Found in all cells, but highest in metabolically active cells such as liver cells o Functions include: Break down fatty acids, organic compounds Produce hydrogen peroxide (H O 2 d2ring the reaction 3 Mitochondria – the “powerhouse” of the cell o Uses chemical energy in food (glucose) to produce the energy molecule ATP o Have smooth outer membrane and inner membrane with numerous folds(cristae) o Matrix: Fluid inside the cristae o Mitochondrial Energy Production Glycolysis – converts glucose to pyruvic acid (in cytosol) for use in the mitochondria Citric acid cycle (also known as the Krebs cycle and the tricarboxylic acid cycle, orTCA cycle ) Breaks down pyruvic acid to CO (i2 matrix) Generates ATP and intermediates for the electron transport chain Electron transport chain – found on the inner mitochondrial membrane Produces the most ATP compared to glycolysis and citric acid cycle Called aerobic metabolism (cellular respiration) Mitochondria requires oxygen to break down food and produce ATP If O2 not in enough quantity, citric acid cycle and electron transport chain shut down Glucose + oxygen + ADP ® carbon dioxide + water + ATP o Mitochondrial disorders – inherited, reduced ATP production. Cells throughout body may be affected. Section 4 – The Nucleus HELP VIDEO: The Nucleus: https://www.youtube.com/watch?v=gGeC0ntvxR8 Nucleus usually the largest organelle The cell's control center (contains all the information to create more than 100,000 proteins found in the human body) Most cells have only 1 nucleus some cells are multinucleated (such as muscle cells) and some have no nucleus (such as red blood cells) Separated from the cytoplasm by a nuclear envelope double membrane (2 layers!) o Perinuclear space found between the two layers of the nuclear envelope o Nuclear pores cover 10% of the membrane; are passages that allow ions, RNA, small molecules to move in/out Contents of the nucleus: DNA deoxyribonucleic acid. Contains all information to build and run the cell Composed of deoxyribonucleic acid subunits called nucleotides Nucleosomes DNA coiled around histones (proteins that help organize and pack DNA) o Nucleosomes are important in mitosis, because it allows for he DNA to organize and condense into manageable structures (chromosomes). Nucleoplasm fluid containing ions, enzymes, nucleotides, and some RNA Nuclear matrix support filaments; may be involved in the regulation of genes o Underneath the envelop, similar to the cytoplasmic elements that give shape to the cell (microtubules, intermediate filaments, etc.) Nuceoli composed of RNA, enzymes, and histones o Most cells contain several (seen as dark staining in areas in the nucleus) o Produces rRNA and ribosomal subunits which are essential for protein production during translation o Prominent in cells that produce lots of proteins (ex. Liver cells, nerve cells, muscle cells) o Cells that produce a lot of proteins have many nucleoli DNA structure DNA coiling degree of coiling can determine level of compactness (the more compact the region of DNA, the less accessible for transcription) o Transcription is similar to copying of DNA to produce and RNA strand. o Chromatin loosely coiled DNA ( found in Nondividing cells) Fine filaments, nucleus appears grainy o Chromosomes tightly coiled DNA (found in dividing cells) Visible as thick fibers under light microscopy Coiling of DNA can regulate how the information in DNA is converted into a protein. o So why is it that DNA is the same in nerve cells and muscle cells, but they look and act so different? Regulation of the DNA leads to some being coiled (and not translated) where other DNA is uncoiled (and is translated) Information storage in the nucleus: DNA contains instructions to produce every protein in the body Gene DNA instructions that code for a protein o Functional unit of heredity o One gene for one protein/polypeptide Genetic code chemical language of DNA instructions o Sequence of nitrogenous bases ( denine, hymine, ytosine, uanine) Triplet code sequence of 3 bases that code for a specific amino acid (a polypeptide is made up of a string of these amino acids) o RNA polymerase makes an RNA copy from this DNA template. It makes a nucleic acid (RNA) Note: RNA does not have thymine. It uses uracil instead. Protein synthesis The role of gene activation in protein synthesis o The nucleus contains chromosomes o Chromosomes contain DNA o DNA stores genetic instructions for proteins o Proteins determine cell structure and function o To produce the proteins, the portion of DNA containing the gene for that protein must unwind which exposes the nucleotide sequence (gene) to be copied into RNA (this process is called transcription) Gene activation requires uncoiling DNA (entire DNA does not uncoil, only regions that are important to a gene to be copied into RNA) o Promoter region of DNA that regulates gene transcription (copying of RNA) o Terminator stop signal to terminate transcription Transcription copies instructions from DNA to mRNA (occurs in nucleus) o Utilizes the enzyme NA polymerase to produce a strand of senger RNA (mRNA) sequence of ribonucleic acids that complement the DNA sequence. Translation ribosome used to read the code in the mRNA strand o Occurs in the cytoplasm of eukaryotic cells o Assembles amino acids into a polypeptide chain Protein processing occurs in the rough endoplasmic reticulum and golgi apparatus o End product of processing is a "mature" protein (can be inactive or active) Note: Base pairing rule is AT, CG. However, RNA lacks thymine, it is relaced it with Uracil. So if DNA template = ATTCGCAT, RNA copy = UAAGCGUA Differentiation Note since all somatic cells have the same DNA: o All cells carry complete DNA instructions for all body functions o Cells specialize orifferentiate To form tissues (liver cells, fat cells, and neurons) By turning off all genes not needed by the cell o Differentiation depends on which genes are active and which are inactive. Protein synthesis: HELP VIDEO: Protein synthesis (trancritpion and translation): https://www.youtube.com/watch?v=6YqPLgNjR4Q A transcription of mRNA o A gene is transcribed to mRNA in three steps Gene activation DNA to mRNA RNA processing Step 1: Gene activation Uncoils DNA, removes histones Start (promoter) and stops codes on DNA mark location of gene o C oding strand is code for protein o Template strand is used by RNA polymerase molecule Remember, DNA is double stranded, so only one strand acts as the template strand for the transcription (copying it into an RNA strand) of a gene Step 2: DNA to mRNA Enzyme RNA polymerase transcribes DNA o Binds to promoter (start) sequence o Reads DNA code for gene o Links together nucleotides (ribonucleic acids) to form messenger RNA (mRNA) o mRNA is he complement of DNA template strand, remember uracil replaces hymine Step 3: RNA processing At stop signal, mRNA detaches from DNA molecule o Code is edited RNA processing) o Unnecessary codes (introns removed from the mRNA strand o "Good" codes (exons) spliced together o Triplet of three nucleotides don) represents one amino acid o Note: RNA processing must occur before the mRNA strand can leave the nucleus of eukaryotic cells (leaves nucleus through a nuclear pore) Translation: mRNA moves to a ribosome in cytoplasm mRNA bind s to ribosomal subunit o tRNA (transfer RNA) delivers amino acids to mRNA/ribosome complex o The tRNA has a specific amino acid attached to it tRNA anticodon binds to mRNA codon (sequence of three nucleotides on the mRNA strand) o One mRNA codon translates to one amino acid Enzymes join amino acids together by forming a peptide bond between them o Polypeptide chain has specific sequence of amino acids At stop codon, the mRNA and ribosome components separate How the nucleus controls cell structure and function Two levels of control a. Direct control through synthesis of: i. Structural proteins (cytoskeletal components, mebrane proteins, including receptors) ii. Secretions (in respone to the environment) b Indirect control over metabolism i. Regulation of enzyme synthesis Cell life cycle: Most of a cell's life is spent in a nondividing state (known as iterphase ) Body (somatic) cells divide in three stages 1. DNA replication (occurs n interphase) duplicates genetic material exactly 2. Mitosis divides genetic material equally 3. Cytokinesis divides cytoplasm and organelles into two daughter cells 1. Note: mitosis occurs in somatic cells while meiosis occurs in germ cells (sex cells). Meiosis produces daughter cells that have half the genetic material. 2. Note: mitosis occurs in somatic cells while meiosis occurs in germ cells (sex cells) Mitosis simply has to do with the nucleus, where cytokinesis is the whole cell. o Interphase 1. The nondividin
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