Human Physiology outline
Human Physiology outline Bio 242
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This 79 page Class Notes was uploaded by Caroline Sullivan on Tuesday February 16, 2016. The Class Notes belongs to Bio 242 at University of Rhode Island taught by Barbara Van Sciver in Spring 2016. Since its upload, it has received 73 views. For similar materials see Intro Human Physiology in Biology at University of Rhode Island.
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Date Created: 02/16/16
EXAM ONE 12/10/2015 September 6, 2013 Physiology (function, how stuff happens) vs. Anatomy (structure) Teleological (why) vs. mechanistic (how) Casual Chains: ____ -> ______ -> _____ -> etc. Organization: o Atoms o Molecules o Cells o Tissues: group of cells with similar origin, structure, and function o Organs: 2+ tissue types organized to carry out a particular function o Organ System: 2+ organs organized to carry out a particular function o Organism The Cell: o Nucleus- genetic material (DNA) o Cytoplasm All stuff outside of nucleus o Cytosol All stuff outside of organelles o Cell membrane (primarily lipids) Semi-permeable o External Environment- outside of body o Internal Environment- inside body and outside of cell o Extracellular Fluid (ECF)- fluid outside the cell Plasma- liquid part of the blood Interstitial fluid- fluid that bathes cell o Intracellular Fluid (ICF)- fluid inside the cell Same as cytosol o Differentiation DNA -> genes -> code for synthesis of particular proteins Proteins that a cell makes determines cell function Different genes are turned off in certain cells and on in others o Different cells make different proteins o Basic Requirements of Cells: Oxygen- respiratory and cardiovascular systems Obtain nutrients- digestive and cardiovascular systems Eliminate CO2- respiratory and cardiovascular systems Eliminate wastes Detect and respond to environmental changes Control exchanges between outside and inside of the cell Move stuff around inside of the cell- internal transport Make proteins Reproduction o Cells have a specialty Tissues: o Primary tissues 1. Connective Tissue: binds, anchors, and supports other tissues blood, bones, tendons, cartilage, adipose characterized by having a large amount of extracellular matrix (ECM) o EX: Bone- osteocytes Blood- plasma and suspended elements (RBC, WBC, platelets) 2. Nervous Tissue: generate and transmit electrical impulses Glial cells- supportive cells Neurons- transmit electrical signals o Dendrites- receive signal o Cell body- nucleus o Axon- neurotransmitters at end Dendrite -> cell body -> axon Electrical impulse can synapse onto: Next neuron Muscle cells- contract muscle Glands- secretion Neuron types: o Afferent: PNS to CNS o Efferent: CNS to PNS “exit” CNS o Interneurons: completely inside CNS Most neurons Only use glucose as a fuel Fragile Need oxygen Don’t reproduce Not good at repair 3. Muscle Tissues: Contraction Generate force o Skeletal Muscle: Multinucleated Striated- striped, arrangement of contractile proteins Long, cylindrical Voluntary o Cardiac Muscle: Striated Involuntary One nucleus o Smooth Muscle: Not striated One nucleus Enclose hallow tubes and organs Involuntary 4. Epithelial Tissue Lines hallow tubes and organs o Lumen= hallow inside of tube Barrier o Regulated Covers the body o Epidermis Stratified- layers of cells Not stratified- “simple”- one layer of cells Glands o Endocrine- secrete hormones directly into the blood Ductless glands o Exocrine- secrete to the outside of the body or to the hallow tubes of the body Ducts Homeostasis o Maintenance of a relatively steady state of the internal environment Concentration of glucose in our blood Temperature Blood pH: 7.33-7.45, above alkatosis, below asatosis Volume- blood pressure o Maintain homeostasis through negative feedback mechanisms The response to a chain of a controlled variable is in opposition to the original change Example: Thermostat set is 68F (set point)-> temperature drops and the furnace turns on to turn temperature up-> temperature goes up and the AC turns on to lower temperature Temperature hovers around the set point all day o Positive feedback systems The response to a change is in the same direction as the change, enhances the change Example: when go into labor and have contractions, the brain releases oxytocin-> more uterus contractions-> more oxytocin Chem Review o Solution- a type of mixture where the particles are so small that they dissolve- dissolve a solute in a solvent o Matter- anything that has mass and occupies space Weight- affect of gravity on the matter Mass- the amount of matter that something consists of o Protons- positive charge, in nucleus o Neutrons- neutral charge, in nucleus o Electrons- negative charge, orbit around the nucleus Most of the atom is empty space o Humans are manly made of C, H, O, N o For every proton, atoms have an electron o C 12/6- Top- atomic mass (given in amu)= number of protons and neutrons Electrons don’t contribute to mass Bottom- atomic number= number of protons o Different numbers of neutrons= isotopes Example: carbon 13, carbon 14 o Chemical Bonding- how molecules are made Each orbital can hold 2 e- max The first shell has 1 orbital= 2 e- The second/third shell has 4 orbitals= 8 e- Energy benefit for an atom/most stable to have its outermost shell (valence) filled- valence e- Ionic bonds Relatively weak bonds Between two ions- one positive and one negative o Cations-positive charge o Anions- negative charge o Electrolytes- ions in a biological system One atom gives up e-/ one atom accepts e- to fill outer shell to become more stable o NaCl Disassociate in solution Covalent Bonds Sharing of electron pairs Involved electrons are in valence shell o CH4 Do not disassociate in solution Stronger than ionic bonds o H20 Universal solvent 75% of the cell’s volume is water Humans are 40-80% water Bent molecule Polar O is more electronegative (attraction of e- pairs) than H Electroneg: O>N>C=H Polar vs. Nonpolar o Polar- carries a charge because e- pairs are attracted to on atom more than another o Nonpolar- doesn’t carry a charge because e- pairs are shared equally o Polar molecules dissolve in water- hydrophillic o Nonpolar molecules do not dissolve in water- hydrophobic Hydrogen Bonds o Form between water molecules o A bond between a H atom and a nearby O, N, or F o Kinetic energy- energy of motion: atoms always bumping into each other o Creates surface tension of water o Bonds break and reform, break and reform o Cohesion- binding between the same kind of molecules o Adhesion- binding between different types of molecules Generally between solids and liquids o Adhesion and Cohesion cause a meniscus o Molecular Weight Add amu’s H20- 18 amu C6H12O6-180 amu Hemoglobin- 65,000 amu o Diffusion vs. Osmosis Diffusion- movement of molecules from area of higher concentration to area of lower concentration of those molecules Through membrane, air, liquid When equal concentrations, equilibrium, still move but in ratios equal to each other Osmosis- diffusion of water down its concentration gradient through a semi permeable membrane Kidney’s use 80% of their energy moving salt-> water follows Side with more particles- more osmotic pressure Osmolarity- number of solute particles in a solution o The size of the particles doesn’t matter, only the number o Chemical Reactions Reactants (substrates)- left side Products- right side CO2(g) + H2) (l) <-(carbonic anhydrase)-> H2CO3 (aq) o Carbonic acid o 100 seconds for 1 reaction w/out enzyme o 1 second for 1 million reactions w/ enzyme *need to balance *can be reversible Enzymes Proteins- complex relatively large 3D molecules Catalysts- speed up reaction rate o Carbs –(salivary amylase)-> sugars Specific- only catalyze certain reactions Not changed- not part of the reaction Recyclable- can be used over and over again Active sites- “holds” substrate Sensitive- optimum pH/optimum temp- 98.6F in people o If not right conditions- unravels Organic vs. Inorganic Organic- contain carbon Inorganic- doesn’t contain carbon except CO2, CO, diamonds Acids/Bases Acid- molecules that increase the H ion concentration of a solution because they disassociate and yield an H+ ion o HCl-> H+ + Cl- o H2CO3-> H+ + CO3- (bicarbonate) pH (potential hydrogen) scale- ranges from 0-14 o 7=neutral, below 7=acid, above 7= base o each number increases by 10 as you go from 14 to 0 o Only free H+ ions that contribute to the acidity Base (alkaline)- molecules that decrease H ion concentration of a solution because they remove H ions from the solution o NaOH -> Na+ + OH- (hydroxyl) o Blood pH: 6.8-asidosis-7.35-7.45-alkolosis-8 o NaOH -> Na+ + OH- (hydroxyl) o HCl-> H+ + Cl- The 2 equations make H2O and NaCl (salt, products of acid/base reactions) Buffers: H2CO3(bicarbonate acid) <-> HCO3- + H+ (bicarbonate ion) buffer system o pH of blood less than 7.35- drives reaction reversely so H+ ions are picked up o pH of blood getting high- reaction makes H+ ions Biomolecules Proteins, carbs, lipidsts Monomers- large molecule with 1 subunits o Saccharides Polymers- large molecules with 2+ subunits o Glucose o Polymerization- bonding of monomers Condensation reactions- o OH-monomer-H o Everytime you add a monomer-> water out Hydrolysis- o Monomer-monomer o Add water back in-> split Carbohydrates o Monomers- saccharides o Saccharide-saccharide =disaccharide o 3+ saccharides- polysaccharide o CHO in 1:2:1 ratio o C1H201 o Source of energy o Store as energy Glycogen (humans) Starch (plants) o Source of Carbon atoms when making molecules o Sugars end in “-ose” o Individual saccharides get absorbed through our gut to our blood and into our cells o Polysaccharides Glycogen- humans store carbs as this Starch- plants store carbs as this o Cellulose- structural form of carbs in plants We don’t have enzymes to break the bonds of cellulose but called roughage- good for GI track Proteins o Monomers- amino acids o 20 amino acids o Large, complex 3D molecules o Diverse o Involved in all biological processes All enzymes are proteins Muscle contraction o Amino group (NH2), carboxyl group (COOH), R group and an H on a C R side chain distinguishes the amino acids from each other o Individual amino acids go into blood and then cells. Our cells make people proteins out of the amino acids o Bonds between amino acids are called peptide bonds- between the carboxyl of one amino acid and the amino group of the next amino acid Formation of a peptide bond by a condensation reaction o 3D structure Primary Structure- sequence of the amino acids Secondary Structure- result of H bonds between atoms on the same amino acid chain Tertiary Structure- result of any other type of bonding except H bonding between atoms on the same amino acid chain Quaternary Structure- result of bonding between more than one amino acid chain o If a protein unravels it will not be able to do its function Lipids o Glycerol o Fatty acids o Fats, oils, waxes, Fats and oils classified based on MP Fats- solid at room temp Oils- liquid at room temp o Bond fatty acid to a glycerol= condensation rxn o Functions o Good source of energy- energy rich o Store fats as triglycerides Glycerol and 3 fatty acid o Make up cells membranes o Repel water o Simple lipids Glycerol and 3 fatty acids- trigyceride o Complex lipids One or more fatty acid chains is replaced by something else Phospholipid Glycerol, 2 fatty acid chains, and phosphate group Amphipathic- molecules that have polar regions as well as nonpolar regions o Fatty acid tails- nonpolar, hydrophobic o Phosphate heads- polar- hydrophilic Cell membranes are bilayers- fatty acid tails toward the middle and phosphate heads towards the water Steroids Cholesterol- backbone of steroid hornome Testosterone Estrogen o Adenosine Triphosphate (ATP)- universal energy carrier- “refined fuel” because can’t use the energy directly from glucose ATP-> ADP + Pi + energy The cell Internal membranes o Partition o Compertmentalize- organelles o Different local environments Different enzymes in different organelles Cytoplasm- everything outside the nucleus Cytosol- outside the nucleus but not the organelles Nucleus o Contains DNA- genetic code Made up of genes Different genes code for the synthesis of different proteins o Enclosed by nucleur envelope o Nuclear pores Organelles o Ribosomes Protein synthesis Free- in cytosol, look “free floating” Carry out function in the cytosol Attached- attached to the ER Proteins released into the lumen of the ER to be modified Ribosomes -> ER->golgi apparatus -> exit cell Proteins shipped outside the cell, shipped and used in another organelle, shipped to cell membrane and becomes a part of the cell membrane o ER (endoplasmic reticulum) Rough- has ribosomes attached Protein modification Smooth- no ribosomes attached Lipid synthesis o Steroid hormone synthesis Detoxification Lumen is continuous with the lumen of the rough ER Vesticular transport Out pouching of the membrane of the ER -> eventually pinches off fully -> vesicle made from membrane of the ER -> transported to the Golgi -> membrane of vesicle fuses with membrane of the Golgi -> proteins released to the inside of the Golgi o Gogli Apparatus Proteins are modified to their final state Sorted and packaged according to their final destination o Exocytosis- Secretion of substances from the inside to outside o Endocytosis- Transporting substances form the outside to the inside Pinocytosis- bring small amounts of fluids into the cell- “cell drinking” Phagocytosis- bring solids into the cell like microorganisms, debris- “cell eating” Only certain cells – ex: WBC Detection of thing brought into cell -> phagosome formation (kept isolated from the rest of the cell) -> delivery to lysosome and digestion -> release of particle into cytosol o Lysosomes Around 300 per cell Contain digestive enzymes for phagocytosis and damaged organelles Low pH Lysososome Storage Diseases Pompe’s Disease o Glycogen builds up instead of being broken down Tay-Sachs Disease o Build up of lipids o Apoptosis Cell death Early cells are programmed to die at a certain time so that other cells can take over o Peroxisomes Membrane enclosed Contain enzymes oxidative enzymes- use oxygen to strip off hydrogens from specific molecules to detoxify them H202 “harmful” -catalase-> H20 + O2 “harmless” o Mitochondria Inner and outer membranes Very inside- matrix Inner folds- christae 6CO2 + 6H2O -> C6H12O6 + 6O2 photosynthesis Cell’s powerhouse Prepare nutrient molecules from the final extraction of energy C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy Energy = ATP Cellular respiration Contains its own DNA- replicate o Cytoskeleton Anchors, holds position, moves stuff around inside the cell, maintain cell shape Microtubules Structure o Largest o Hallow tubes o Made from the protein tubulin Function: o Tension bearing o Shape and support the cell o Cell division o Guide secretory vesicles “highways” Kinesin “walks” along the microtubule carrying the vescle- every step requires a molecule of ATP Cilia o Projections on cells o Function: wave o Lines respiratory tract- get debris out Flagella o Sperm cell tall o Function: movement Microfilaments Smallest of the 3 Twisted chain Actin Functions: o Resist pulling o Support cell shape Microvilli- small folds that line small intestine, used to increase surface area to increase absorption o Cell motility Contraction Myosin Amoeboid movement Intermediate filaments Structure: o Keratin or vitentin o Fibers wound into thicker cables Function: o Hold nucleus into place o Tension bearing Cellular Respiration o C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy (heat and ATP) o Transfer bond energy of molecules to bonds of ATP o Glucose- raw fuel Cant use energy directly o ATP- refined fuel Can use directly o Transferring energy Transfer of e- Are usually accompanied by Hydrogen atoms Oxidation-Reduction Reactions One molecule loses an electron (oxidation) One molecule gains an electron (reduction) The more reduced a molecule is, the more energy is stored o Coenzymes NAD+ Accepts e- from other molecules and becomes reduced This reaction forms NADH, which can donate e- Most energy releasing reactions in the cell produce NADH (or similar reduced coenzymes) ATP Most energy-consuming reactions require ATP Cells need a way to connect the 2 coenzymes, that is, to transfer energy from NADH to the P-O bonds between phosphate groups od ATP This transfer accomplished in a process called oxidative phosphorylation- The coupling of the oxidation of NADH NADH- -> NAD+ + H+ +2e- +energy To the production of ATP: Energy + ADP + Pi -> ATP Oxidation of glucose releases energy Cells use it to make ATP Many step process _________________________________ Material for exam one (slide 206) Autonomic Nervous System Sympathetic- “Fight of flight” o Speeds up heart rate o Slows movement of digestive tract Parasympathetic- “Rest and digest” o Slows heart rate o Speeds up digestive tract Both branches are active- tonic activity Effectors: cardiac muscle, smooth muscle, glands, GI tract Dual innervation: innervated by both sympathetic¶sympathetic o Exceptions: adrenal glands (only symp.), blood vessels (only symp.), salivary glands (parasymp=large amounts of watery saliva/symp=small amounts of mucusy sticky saliva) CNS to Effector: 2 neuron change-> synapse Parasympathetic: First neuron cell body lies in sacral or cranial part of CNS (longer) (preganglionic), second neuron is short and close to effector- terminal ganglion (postganglionic) Sympathetic: first neuron cell body lies in thoracic or lumbar part of CNS (shorter) (preganglionic), second neuron is longer and starts near CNS- sympathetic chain ganglion (postganglionic) OR Two neurons are equal length, second ganglion called collateral ganglion o Adrenal Glands (exception): innervated by sympathetic; endocrine portion releases secretions into the blood; epinephrine released on sympathetic command Receptors on effectors and cell bodies of postganglionic cell bodies Neurontransmitters: o ACh- acetylcholine Released from parasympathetic and sympathetic preganglionic neurons Binds to receptors on postganglionic AP down second neuron 1- Release of ACh again in parasympathetic 2- Release of NE in sympathetic *Need to release different postganglionic neurontransmitters so that effectors are able to do different things o NE- norepinephrine o E- epinephrine Receptors: o Cholinergic: receptors for ACh Nicotinic cholinergic: found on cell bodies of post ganglionic neurons Muscarinic cholinergic: found on effectors of parasympathetic o Andregenic: receptors for NE and E Found on effector organs in sympathetic When sympathetic is dominating E is released into the blood -> binds to andregenic receptors Parasympathetic AP travels down 1 neuron/preganglionic-> release ACh-> receptor: nicotinic-> 2ndAP (postganglionic)-> release ACh-> receptor: muscarinic- > decrease HR Sympathetic st AP travels down 1 neuron/preganglionic-> release ACh-> receptors: nicotinic-> 2ndAP (postganglionic)-> release NE-> receptor: andregenic-> increase HR Adrenal: AP-> release E-> receptors andregenic-> increase HR Afferent Neurons Periphery to brain and spinal cord o Special senses o Somatosenseations- skin o Proprioception- joints o Visceral- insides Receptors: touch (skin), light (eyes) o Changing one form of energy to electrical energy in the form of APs Transduction: changing one form of energy to another Modalities: another name for energy forms, different forms of energy Stimulus Intensity- How do we know something is warm or hot? Cool or freezing? Strong pressure or gentle? Etc. o Frequency of action potentials o Number of receptors activated strong stimulus= more frequent, more receptors activated Perception o The world is not how we perceive it o Dogs hear and smell different things than we do Adequate Stimuli o The stimulus that normally activates a particular receptor type o Eye: normal= light, close eye and press on eyeball (mechanical) =activating receptors (see light) Law of specific nerve energies o A given sensory receptor is specific for a particular energy form or stimulus type Receptor types: o Thermoreceptors- temperature/heat o Photoreceptors- lights, found in retina o Chemoreceptors- certain chemicals; taste buds/olfactory receptors/CO2 concentration/ H+ concentration o Baroreceptors- pressure o Mechanoreceptors- mechanical stress=stretching/bending; hair cells in ear o Nociceptors/Pain receptprs- pain o Osmoreceptors- osmolarity= solute particles in solution Adaptation o Tonic Receptors- when a stimuli is first applied, those neurons/receptors will continue firing the entire time the stimuli is being applied; do not adapt; ex: hold up held and neck whole time o Phasic Receptors- respond to a stimulus when it is first applied with a burst of firing to the CNS then the rate of firing will decrease until or unless the stimulus is removed; adapt Acuity o the receptor field size varies inversely with the density of the receptors there o (smaller receptor field -> greater the acuity) Pain Receptors o Do NOT adapt- If we adapted to pain we wouldn’t take measures to stop the pain o Mechano pain receptors- physical: crushing, pinching, tearing o Thermal pain receptors- extremes in temperature o Polymodal pain receptors- all sorts of painful stimuli including chemicals released from damaged cells Prosoglandins- chemicals released from cells that cause pain Aspirin- inhibit aspirain Skeletal Muscle Physiology Muscle fiber= a skeletal muscle cell Multimucleated Striated Voluntary Attached to bones via tendons Organization: o Surrounded by connective tissue and modified on either end to form tendon o Bundles within muscle= fascicle o Fascile= bundle of muscle fibers/muscle cells o Muscle cells/muscle fibers= bundle of myofibrils Long, cylindrical, multinucleated, striated Striation due to contractile proteins Myofibrils are a component of a muscle cell o Myofibrils= made of sarcomeres o Sarcomeres= made of actin and myosin (proteins) o Between Z lines= sarcomere- functional unit of contraction o Blue= Sarcoplasmic reticulum- surrounds myofibrils and stores Ca++ ions o Filaments Thick= myosin- does not reach to the Z line Has cross-bridges on myosin head that have actin binding sites and ATPase site Cross-bridges are oriented facing out Two myosin molecules are bound at their tale ends Do NOT shorten during contraction Thin= actin- does not extend to the middle; attached to the Z line Made of spherical molecules Looks like a twisted pearl necklace- double helix Each molecules has a binding site for myosin Tropomyosin- long, string-like molecules; covers myosin binding sites at rest Troponin- stabilizes the tropomyosin Do NOT shorten during contraction- are pulled toward the center o Sarcomere Z line Thin filament extends to Z line Thick filaments don’t extend to Z line Thick filament cross-bridges Power stroke- bending in of myosin cross-bridge; requires ATP; attach and detach and repeat EEP on motor endplate-> AP on both sides along membrane and down T tubules-> Ca++ ions released from the sarcoplasmic reticulum-> Ca++ enters sarcomere-> Ca++ binds to troponin-> tropomyosin moved off myosin binding sites on actin molecules-> actin and myosin bind-> ATP is split into ADP+Pi-> Bending in/power stroke o Nothing happens until attachment sites are exposed ATP binds to cross-bridge-> ATP is split to ADP + Pi-> cross-bridge is energized In order for a detachment to occur between the myosin cross-bridge and the actin molecules, a fresh ATP has to bind to the myosin cross- bridge For a while when we die, our muscles run out of ATP-> no detachment-> extreme contraction for a couple hours-> muscles relax because proteins start to break Excitation-control coupling o Excition from AP to contraction: EPP- AP along membrane and down T tubules- Ca+ released from SR and binding to troponin- tropomyosin moved off binding sites- contraction o Excitement coupled to the contraction The Twitch o All Ca++ allowed to go back into the sarcoplasmic reticulus o Single rapid contraction and relaxation of muscle fibers Summatation nd st o 2 stimulus ndcurs before the muscle relaxes from the 1 stimulus-. 2 twitch is greater Fatigue o Reduction in ability of muscle to generate force Muscular fatigue- energy reserves are being depleated, lactic acid is building up IN THE MUSCLE Neuromuscular fatigue- motor neuron can’t keep up making ACh fast enough to sustain contraction Psychological fatigue- CNS is not activating the motor neurons to the same degree (exercise painful and monotonous) Tetnus o Occurs when a frequency is so fast that no relaxation occurs, smooth muscle contraction Motor Unit o One motor neuron and all the muscle fibers it innervates o Motor Unit Recruitment- activating more motor neurons in a muscle in order to develop different grades of strength o Asynchronous Motor Unit Recruitment- used to make sure certain muscles remain the same length Sources of ATP o Glycolysis- 1- step process- 2 ATP/glucose o Oxidative phosphorylation- ETC- many step process- 34 ATP o Creatine Phosphate- one step process Creatine-P + ADP -> ATP + creatine Fiber Types- based on primary means that a particular muscle fiber gets its ATP o Oxidative- ATP mainly from oxidative phosphorylation; have lots of mitochondria; requires oxygen; highly vascularized; more fatigue resistant; lots of myoglobin (supports fibers) Fast oxidative Slow oxidative o Glycolytic- ATP mainly from glycolysis; have less mitochondria; does not required as much oxygen; less vascularized; less fatigue resistant because don’t make as much ATP Fast glycolytic o Any muscle- half fast/half slow, all kinds of fibers o As age- diameter of skeletal muscle gets smaller, 30% of fibers lost, motor neurons don’t make ACh as efficiently anymore The Muscle Spindle o Spindle shaped o Have Afferent innervation- appraise CNS about conditions at muscle (length, position, etc)-> coordinates movement Cardiac Physiology One nucleus Short, branches fibers Striated based on arrangement of actin and myosin Rely heavily on oxidative phosphorylation for ATP- lots of mitochondria (40% of volume) Connected by gap junctions- communication junctions o 4 chambers- want both atria contracting at the same time, want both ventricles to contract at the same time-> rapid transmission of AP Blood Flow through the Heart o Pulmonary- heart to lungs o Systemic- heart to systemic cells o Valve between RA/RV- tricuspid o Valve between LA/LV- bicuspid o Valve from RV to lung- pulmonary semilunar valve o Valve from LV to systemic circulation– Atrial semilunar valve o Path of Blood: Blood leaves Left ventricle (high in oxygen, low in CO2) Gas exchange from blood to the cells Blood returns to heart via right atrium (low in oxygen, high in CO2) Pumped into RV via tricuspid valve and out of heart through the semilunar valve to pulmonary arteries to the lungs (oxygen in, CO2 out) Blood returns to LA via pulmonary veins (high ocygen, low CO2) LA -> LV through bicuspid valve and out of the heart through semilunar valve to systemic arteries *pulmonary veins are high in oxygen Valves o Not innervated o Opened because pressure differences o Pressure builds up in atria opens tri/bi o Pressure builds in venricles closes tri/bi and opens semilunar o Bi/tri valves don’t open because chordea tendinae Blood pressure o Force exerted on the vessels walls due to volume of blood in the vessel and the compliance of the vessel (stretch ability) o Arterial blood pressure taken o Hypertension- chronically high blood pressure- heart has to work harder to open the valves Blood is delivered to the organs in parallel circuits Left side of heart is strong- has to pump blood through the body Layers of the Heart o Endocardium- specialized epithelial cells that line the inside of the heart o Myocardium- muscle layer of the heart o Epicardium- thin layer of cells on the outside of the cells o Pericardium- sac that surrounds the heart; anchors and protects the heart; has an outside layer and an inside layer; fluid between 2 layers in pericardial fluid=lube o Myocardium: Thicker in left side of the heart 99% of cells are called contractile cells- contract 1% of cells are called autorhythmic cells- depolarize the threshold spontaneously- generate their own AP spontaneously Shorter, branched cells Striated One nucleus Connected by gap junks Connected by intercalated disks: Desmosomes- hold cells together but allow things between cells; gap junctions: tiny tunnels that allow small molecules and ions to go from one cell to the next * no gap junction between the atrial cells and the ventricular cells- allow contraction at different times in the chambers electricity flow: SA node to muscle cells o Electrical Conduction SA node- In right atrium, top left AV node- In between atria and ventricles junction The ONLY electrical connection between the atrial cells and the ventricular cells Bundle of His- left and right branches going to ventricles respectively Purkinje fibers- in walls on ventricles *all autorhythmic cells AP of the Contractile cells SA cells spontaneously get to threshold and generate AP and travel to all cells in atria- interatrial path and from SA node to AV node- intermodal path-> electricity goes into ventricles via Bundle of His-> electricity goes into walls of ventricles via Purkinje fibers Starts with SA node because cells in SA node polarize to threshold the fastest of all the cells that make up the electrical conduction system of the heart-> SA node called normal pacemaker of the heart AP spread through the atria to the AV node where condction slows AV node at rest polarizes 70 times a minute-> resting heart rate Fibrilation- random, uncoordinated excitement (AP) and contraction of cardiac muscle cells Dangerous; use defibrillator to get SA node back to normal Ectopic (out of place) Pacemakers- other cells that set pace of heart that are not in the SA node Heart Block- electricity blocked from going into ventricles Complete heart block- SA node fires AP to atria and all atrial cells contraction 70/minute and purkinje fires 30/minute Arrhythmias Tachycardia- too fast resting heart reate; >100 beats/minute Bradycardia- too slow resting heart rate; < or around 50 beats/minute Heart Block Fibrilation AP of the cardiac autorhythmic cells No resting membrane potential Have pacemaker potential which is based on cells cyclical changes in their permeability of K+ Permeability to sodium does NOT change, EVER Permeability to K+ getting out is low and Na+ is leaking in-> drift up to threshold-> pacemaker potential At threshold: Increase to permeability to Ca+ -> Ca+ diffuses in (Ca+ influx, 2 positives) -> at peak (AP), change in permeability to K+ -> K+ goes out-> membrane repolarizes (K+ efflux) Na+ pumped out, K+ pumped in No resting membrane potential Pacemaker potential-> permeability for Na+ does not change/ permeability for K+ changes cyclically (-70) low permeability to K+ -> most K+ stuck inside cell// Na+ leaky channels allows some Na+ to diffuse in steadily -> drift to threshold (-55) -> increase in permeability to Ca++ -> Ca++ influx= rising stage of AP -> increase permeability to K+ at peak -> K+ efflux= falling stage of AP o How sympathetic and parasympathetic nervous systems effect heart rate of AUTORHYTHMIC CELLS Giant heart with giant SA node- look in kitty’s PARASYMPATHETIC AP arrives (on preganglion neuron) at NR and releases ACh -> AP arrives (on post ganglionic neuron) at MR and releases ACh Binding of ACh to MR on SA node (leads to channel regulation)-> increase in permeability to K+ -> slower drift to threshold (less positives in): takes a lot more Na+ to get to threshold because lots of positives out -> AP -> slower heart rate SYMPATHETIC AP arrives at NR-> AP arrives at AR and releases NE AP arrives at adrenal gland-> release E via blood Binding of NE and E to AR on the SA node-> decrease permeability to K+ -> faster drift to threshold: trapping positives inside -> faster heart rate o AP of Contractile Cells (-90 to positive) Rising phase, increase in the permeability to Na+ -> at peak, increase to permeability to Ca++ -> Ca++ goes in very slowly- >plateau phase/refractory period (250 milliseconds):remains polarized for so long= CANNOT get another AP= no tetnus of the heart-> falling phase, increase in permeability to K+ (K+ efflux) Cannot have 2 AP’s at one time Contraction: AP that causes contraction is the same length of time as the AP-> NO summation/tetnus in contractile cells For cardiac muscle contraction, Ca++ comes from sarcoplasmic reticulum and from the ECF Stroke volume (volume of blood pumped by each ventricle per beat) X Heart rate (beats per minute)= Cardiac output (volume pumped per minute) o 70 mL x 70= 4900 mL of blood = 5 liters of blood Systole: contracting and emptying stage of a heart chamber o More blood in the arteries Diastole: relaxing and filling stage of a heart chamber o Less blood in the arteries *if doesn’t say atrial, it is ventricles Blood Pressure: volume of blood and compliance of vessels o Blood empties in arteries-> arteries expand to accommodate extra blood-> blood pressure is higher in systole Normal BP= 120 mm Hg/80 Heart at rest stays in diastole longer o Pulse pressure= systolic –diastolic *normal= 40 mm Hg o Mean (Average) Arterial Pressure= diastolic + 1/3 pulse pressure normal= 80 + 1/3(40)= 93.333333333…. Hypertension- chronic high blood pressure of the arteries o Sometimes can’t figure out causes, a person just has high blood pressure Heart sounds o Lub: from tricuspid and bicuspid valves shutting o Dub: from pulmonary and semilunar valves closing Valve problems: o Stenotic: valves become stiff and rigid; valve doesn’t open completely-> blood creates turbulence-> hear a whistling sound o Insufficient: “Leaky Valves”; valve doesn’t close completely-> when ventricles contract some of the blood goes backwards-> hear a gurgling sound Rheumatic Fever o Complication of strep throat o Antibodies as defense system to attack antigens (normal) o Rheumatic endocarditis- antibodies attack a person’s own valves-> scarred valves-> don’t open or close completely Ischemia o Coronary circulation- supplies blood/nutrients to the heart If problem, cells that coronary artery supplies are deprived of CO2/O2 If a tissue is deprived of a normal, adequate supply of oxygen, the tissue it is called ischemia Atherosclerosis o Gradual, progressive blockage of vessels o Most dangerous when vessels are part of coronary circulation or vessels supply brain tissue o Steps: Fatty streak- cholesterol All blood vessels lined with specialized epithelial cells called endothelium Cholesterol builds up under endothelium Formation of artheroma (tumor) Smooth muscle in the area starts to migrate to the fatty streak and starts to divide and reproduce Abnormal cell reproduction that is benign Tumor + fatty streak = plaque Overlying endothelial cells being strained Fibroblasts (scar formers) invade the area where they see damage and form a connective tissue cap over the area- “-sclerosis” Calcium precipitates in the sclerosis cap and hardens it Hardening of the arteries Thrombus Caps/tumor breaks through endothelial lining-> endothelium splits Embolus Thrombus breaks off Can block vessels Cholesterol o From diet o Made in the liver Lipitor can stop liver from making cholesterol Check liver enzymes o Lipid, not soluble in water (blood) -> needs to be tansported in the blood from proteins o HDL- High Density Lipoprotein- lipid and transporter protein Mostly protein, little cholertorl “Good” cholesterol o LDL- Low Density Lipoprotein- lipid and transporter protein Mostly cholesterol, little protein “Bad” cholesterol Blood Vessels o Reconditioning organs- digestive tract, liver, kidneys- maintain composition of the blood to add or remove things from the blood o Brain blood flow doesn’t change during rest and exercise Organization of blood vessels o Blood leaves heart via arteries (wide radius, rapid flow) o At organs, arteries branch to arterioles o In organs, arterioles branch into capillaries- exchange sites o Venuoles leave the organs o Blood returns to heart via veins o Arteries- high blood pressure o As vessels get smaller- blood pressure drops (down pressure gradient) to keep blood flowing -> no gradient, no flow Endothelial Cell Functions: o Physical lining o Secretions Vasodilators- smooth muscle in area relaxes Vasoconstrictors- smooth muscle in area contracts Clotting o Regulate capillary permeability Capillary= one endothelial cell thick o Immune functions General Anatomy of the Blood Vessels o Tunica externa (outer layer) Primarily connective tissue o Tunica media (middle layer) Primarily smooth muscle o Tunia intima (inner layer) Primarily endothelial lining Ateries-> arterioles-> capillary- venuole-> Vein o Vein has less muscle than arteries o Vein is highly sustainable Blood Flow=pressure gradient(difference in pressure) / resistance o Determinants of resistance: Length of vessels- remains constant through adulthood Viscosity- thickness of the liquid; usually constant Radius of the vessel- changes; can be adjusted in the arterioles Arteries o Blood is ejected into the arties- pulmonary and systemic o Lots of collagen= strength o Lots of eleastin= about to recoil-> pressure reservoir Systole- highest pressure: arteries balloon out Diastole- lowest pressure: arteries recoil o Relatively large radius-> low resistance to flow Arterioles o Smaller radius than artery o Resistance to low is higher than arteries o No elastin Known as “major resistance vessels” (because 3 about) o Adjustable-> change TPR (Total Peripheral Resistance- resistance to flow at the periphery): can be changed by adjusting the radius of the arterioles o Helps maintain arterial blood pressure (critical)-> driving force that gets blood to brain and organs/ maintains pressure upstream because smaller radius in arterioles o Normal arteriolar tone- partially constricted Increase sympathetic activity- constriction Exercise-> increased sympathetic activity-> generalized vasoconstriction of the arterIOLES= increase in TPR Need local overrides-> local vasodilation o Exercise= use more oxygen (decrease [O2])-> decrease oxygen concentration locally-> local vasodilation o Exercise= build up of CO2 (increase [CO2])-> increase in CO2 concentration locally -> local vasodilation o Exercise-> Increase H+ ion concentration-> local vasodilation CO2+H2O-> H2CO3 (carbonic acid)-> H2CO3-> H+ + HCO3- Decrease sympathetic activity- relaxation Decrease Blood pressure -> baroreceptor-> brain-> Increase symp activity-> Increase TPR-> arterioles constrict-> increase in blood pressure Decrease Blood pressure -> baroreceptor-> brain-> increase symp activity-> -> cardiac output-> increase blood pressure Capillaries o Exchange sites for O2/CO2/wastes o Permeable, has pores Nonpolar substances can get right through Small water soluble molecules/ions go right through pores Some proteins (exchangeable proteins) exchanged by vesicles- vesicular transport- takes energy (Generally) Plasma proteins CANNOT cross capillary wall under normal circumstances Plasma proteins are made in liver Some involved in immune system, clotting, transport Diffusion across membrane/ through pores Bulk flow- have a fluid that has more than one component, the flow is all together Bulk flow out of capillary=filtration Bulk flow into capillary= reabsorption Plasma proteins are NOT part of bulk flow Plasma and interstitial fluid should be identical o RBCs have to squeeze through capillaries-> very small o One endothelial cell thick o Very porous except in Blood Brain Barrier Determinants of Bulk Flow: Blood pressure =120/80/Mean arterial pressure= 93 mHg o Capillary blood pressure: favors filtration (bulk flow out) When blood is entering the capillary, the blood pressure is about 37 mHg When blood Is draining from the capillary, the blood pressure is about 17 mHg o Plasma protein colloid osmotic pressure: favors reabsorption Protein concentration high in capillary Capillary blood pressure is about 25 mHG o Interstitial fluid hydrostatic pressure: favors reabsorption Capillary blood pressure is 1 mHg Beginning: favoring reabsorption: 26 mHG End: favors reabsorption: 37 mHg o *Interstitial Fluid osmotic pressure 0 mHg- no effect o When plasma proteins leak out-> redness, swelling, pain o If in a car accident: Blood pressure falls -> Mean arterial pressure falls-> beginning of capillary blood pressure falls-> less filtration o If drop in number plasma proteins-> Edema= excess interstitial fluid Plasma proteins are responsible for bulk of reabsoprtion Conditions with less plasma proteins: Liver Disease, Kidney Disease, Severe Burn Victims, Diet Deficiency Lymphatic System o Structure Overlapping endothelial cells Pressure from interstitial fluid opens flaps o Function Allows excess fluid to be returned to the circulatory system-> about 3 liters a day Allows excess proteins to be returned-> protein becomes part of lymph Has an immune function-> bacterial cells forced into lymph-> in lymph node, phagocytes kill bacteria before getting to the blood o Elephantiasis Blockage of lymth vessels Veins o Structure: Large radius Valves- one way flow back to the heart Little elastin- do not recoil o Function: Blood reservoir At rest, contain 60% of he blood During exercise, increased venous return=increased cardiac output= more oxygen to skeletal muscles Squeezes blood back to the heart when the muscle contracts Cellular Respiration C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy (heat and ATP) Glycolysis – “splitting of sugar” In the cytoplasm No O2 required No CO2 is produced C6H126 (6C’s) -> 2 pyruvate (3C’s each) o Uses: 2 NAD+ o Yields: 2 NADH + H+ to oxidative phosphorylation o Uses: 2 ADP + Pi -> ATP o Yields: 2 ATP If not enough O2 for the next step, pyruvate is converted to lactic acid Linking Step between glycolysis and the Kerb’s Cycle: Per glucose, 2 linking steps because 2 pyruvates Pyruvate (3 C’s) -> Acetyl CoA (2 C’s) + CO2 (1 C) o NADH + H+ to oxidative phosphorylation Acetyl CoA then enters the Kreb’s Cycle: Takes place in the matrix of the mitochondria Oxygen is required Per glucose, 2 Kerb’s cycles because 2 pyruvates Yields: o 3 NAD+ -> 3 NADH + H+ *most NAD+ reduced o 1 FAD -> FADH2 o 3 H2O -> 2 CO2 o 1 ADP + Pi -> 1 ATP per Kreb’s Cycle Electron Transport Chain: (in the mitochondria matrix) NADH + H+ (from glycolysis, linking step, and kreb’s cycle) is being oxidized- dropping off electrons FADH (from kreb’s cycle) is being oxidized- dropping off electrons High energy electrons passed from one component to the next to the next of the ETC o Going from higher energy levels to lower energy levels from one step to the next o Oxidation-reduction reactions down the chain Energy is released as electrons move down the chain Energy is used to phosphorylate ADP + Pi -> ATP Final electron acceptor in the ETC is oxygen Water is generated Net Yield of ATP: glycolysis- 2 ATP/glucose Kreb’s Cycle- 2 ATP/glucose ETC- 34 ATP/glucose Chemiosmotic coupling The production of ATP via a proton (H+) gradient Components of ETC are imbedded in the inner membrane of the mitochondria Electrons are passed down from one component to the next- energy is released Energy is used to pump H+ ions against their concentration gradient (from matrix to inner membrane space) o Moves from area of lower to higher concentration- pump H+ ions diffuse back across membrane through ATP Synthase o Spinning results in phosphorylation of ADP -> ATP Summary of oxidative phosphorylation From glycolysis, the linking step and the Kreb’s cycle o 10 NADH + H+ + 2FADH2 Yields: o 34 ATPs ATP- Adenisine Triphosphate Energy is in phosphate bonds Cell Membranes Selectively permeable o Nonpolar substances can dissolve right through membrane down their concentration gradient Made primarily of lipids- phosphate head and 2 fatty acid tails o Amphipathic- polar head/ nonpolar tail o Bilayers Membrane Proteins o Span entire membrane (amphipathic), just on outside, or just on inside o Different cell types have different membrane proteins o To a large degree, the function of a cell is determined by what membrane proteins are present o Membrane Channels Filled with water Allow VERY SMALL (<0.8 nm) molecules and ions to cross the membrane Water soluble or polar molecules Flow down concentration gradient- high to low concentration Some are specific as to what they allow to go in or out