Anatomy Exam 1 Guide (3) PDF

Lecture 1 ​ Define homeostasis Homeostasis is maintaining a stable internal environment. It helps to bring the body to a point of balance. For example, temperature regulation and blood sugar levels. Receptors (thermoreceptors) will detect stimuli and changes in...

Lecture 1 ​ Define homeostasis Homeostasis is maintaining a stable internal environment. It helps to bring the body to a point of balance. For example, temperature regulation and blood sugar levels. Receptors (thermoreceptors) will detect stimuli and changes in the environment, while effectors (gland cells/muscle) will respond to that change and produce a response. The hypothalamus acts as a thermostat to regulate the body’s set points. ​ Contrast the endocrine system with the autonomic nervous system Endocrine -​ Releases hormones into blood, systemic -​ Broad, whole body -​ Long (min to hr) -​ Hormones travel to receptors on organs via blood -​ Targets all body tissues ​ ANS -​ Electrochemical impulses in neurons -​ Local (synapse) -​ Uses neurotransmitters -​ Short (ms to seconds) -​ Targets neurons, muscles and glands ​ Describe the different pathways sympathetic and parasympathetic axons take from the CNS to their organ targets, and understand the implications for organ function Sympathetic: -​ Preganglionic neuron in cell body -​ One neuron chain (direct synapse)  -​ Somatic motor neuron travels across myelinated axons -​ Only ACh is used as a neurotransmitter -​ Target organs are skeletal muscles, activated when stimulated -​ Organ function: fight or flight, increase O2 to lungs, fast heart rate, release of energy, reaction to threat or danger ​ Parasympathetic: -​ 2 neuron chain -​ Preganglionic neuron cell body is in the CNS while postganglionic neuron is in the autonomic ganglion -​ ACh and NE (norepinephrine) are involved -​ Target organs are smooth/cardiac muscle and gland cells (active all the time) -​ Organ function: rest and digest, slow heart rate, storage of energy, empty bowels and bladder ​ Explain the concept of dual innervation of organs by the ANS Organs are innervated/influenced by both the sympathetic and parasympathetic systems. These systems have opposite effects, but are both used to bring the body to a state of equilibrium, or homeostasis. ​ Explain the role of the hypothalamus and autonomic centers in control of the autonomic nervous system The hypothalamus acts as a master regulator or thermostat, regulating the body’s internal conditions. It receives information from hormones in the blood and the frontal lobe, and sends information to the brain stem/pituitary gland/ spinal cord. These control centers (mostly in the hypothalamus and brainstem) communicate with the ANS to coordinate sympathetic or parasympathetic responses based on the body’s needs. Lecture 2 ​ Describe the neurochemistry – both transmitters and receptor types – for the parasympathetic nervous system  Parasympathetic: -​ Both pre/post neurons release ACh -​ The preganglionic neuron releases ACh, which will bind to a nicotinic receptor on the post ganglionic neuron -​ The postganglionic receptor releases ACh which will bind to a muscarinic receptor on the target organ ​ Describe the neurochemistry – both transmitters and receptor types – for the sympathetic nervous system Sympathetic: -​ Preganglionic neuron releases ACh and binds to a nicotinic receptor on the postganglionic neuron -​ Post ganglionic neuron releases NE, which binds to a NE receptor (adrenergic receptor) on the target organ ​ Explain the terms agonist and antagonist and relate to drugs or chemicals that affect function of the autonomic nervous system Agonist: stimulates the same response in cell as binding neurotransmitter Antagonist: blocks the receptor/action of the transmitter by blocking the binding site Drugs: nicotine will activate both parasympathetic/sympathetic nervous systems as well as skeletal muscle. Muscarine is found in certain mushrooms and activates all muscarinic receptors (difficulty breathing and slow heart rate) ​ Explain the types of adrenergic receptors Alpha 1: smooth muscle contraction Beta 1: cardiac muscle cells Beta 2: smooth muscle relaxation Lecture 3 ​ list functions of blood Transport oxygen and nutrients, defend against toxins, clotting factors, regulating pH, restrict fluid loss in case of injury ​ describe the composition of plasma Blood contains two parts: blood and formed elements (red/white blood cells and platelets) -​ 43-63% of blood volume -​ Majority is water -​ Contains some proteins and electrolytes -​ Gases and hormones ​ Explain hematopoiesis Process of blood cell formation, occurs in red marrow of bones, hematopoietic stem cells form all types of blood cells ​ describe the structure of a red blood cell and relate it to its function  RBC (erythrocyte) -​ Carry oxygen to cells in the body, short lifespan -​ Hematocrit (% of whole blood occupied by RBC’s) -​ Erythropoiesis: formation of new RBC, stimulated by the EPO hormone -​ Biconcave disc to maximize surface area (diffusion of gases) -​ NO NUCLEUS -​ Due to the disc shape, RBC’s can stack and bend easily through blood vessels ​ describe the structure of hemoglobin and its breakdown ​ Hemoglobin (95% of protein in RBC’s) -​ Globular protein with 2 pairs of protein subunits and 4 heme molecules -​ Each heme (pigment) contains an Iron, the Iron is saved and recycled -​ One hemoglobin molecule can bind up to 4 molecules of O2  Hemoglobin can also be recycled, where Heme is striped of Iron and converted to bilirubin ​ describe the different classes of white blood cells and their roles in the body WBC’s (leukocytes) Granulocytes -​ Neutrophil: first in injury response -​ Eosinophil: phagocytes, remove waste -​ Basinophil: release histamine and heparin ​ Agranulocytes: -​ Lymphocyte: B/T-cells (immune stem cells) -​ Monocytes: leave blood to become macrophages -​ ​ explain diseases related to blood: jaundice, anemia, and leukemia Jaundice (yellow) -​ Liver disease, liver fails to process/breakdown RBC -​ Bilirubin builds up in the blood and diffuses into bodily tissues  -​ Gives the eyes/skin a yellow color ​ Anemia -​ Decrease in oxygen carrying capacity of blood -​ May result from iron deficiency, hemorrhage (loss of blood) -​ Not enough RBCs are produced -​ Sickle cell: caused by genetics, mutation of amino acid sequence of hemoglobin Leukemia (cancer of the white blood cell lines) Myeloid: abnormal granulocytes or other cells of marrow Lymphoid: abnormal lymphocytes ​ describe the role of platelets and their role in the blood coagulation process Platelets (not cells) -​ Fragments of megakaryocyte (type of cell found in bone marrow) -​ Important for blood clotting -​ Blood coagulation process: vasoconstriction, feedback loop causes platelet aggregation which blocks the hole in the vessel wall, fibrin forms the clot (coagulation) and traps red blood cells ​ explain the role of fibrin in the role of clot formation, and why tPA is useful in speeding the breakdown of a clot Fibrinolysis: dissolution of clot (plasminogen into plasmin, plasmin breaks down fibrin threads) Fibrin: forms a mesh network around hole in the blood vessel wall, this traps red blood cells and a clot forms tPA (clot-busting drugs): given to speed up the process of fibrinolysis (dissolving a clot) in cases of heart attack and stroke ​ contrast the words thrombus and embolus ​ Thrombus: blood clot (formed by platelets) adheres to blood vessel wall, occurs at sites of arterial disease such as heart attack and stroke ​ ​ Embolus: piece of thrombus may detach and travel via the blood, which may block blood vessels at another body site LECTURE 4 ​ define the terms systemic circulation and pulmonary circulation and trace the flow of blood through each Pressure gradient: blood moves from and area of high to low pressure Systemic circulation: -​ blood passes to organs (except lungs) and back to the heart -​ Systemic arteries (high levels of oxygen) carry blood to body tissues -​ Systemic veins (low in oxygen) carry blood back to the heart ​ Pulmonary circulation: -​ Blood passes to lungs and back to heart -​ Pulmonary arteries carry blood to lungs -​ Pulmonary veins return blood from lungs to left side of the heart Blood flow pattern -​ Right side of heart: receives deoxygenated blood (from inferior and superior vena cava) and brings it to the lungs via pulmonary arteries -​ Left side of heart: oxygenated blood, receives blood from pulmonary arteries and brings it to body tissues via the aorta  RIGHT SIDE, DEOXYGENATED, ARTERIES ** deoxygenated blood goes to lungs, oxygenated goes to heart ** ​ describe the structure of a typical blood vessel, comparing arteries with veins Blood vessel: -​ Tunica intima: innermost layer, endothelium (simple squamous for gas exchange), supported by collagen -​ Tunica media: middle layer, smooth muscle, elastic fibers -​ Tunica externa outermost layer, made of connective tissue (collagen) ​ Arteries: carry blood away from the heart (contain more smooth muscle and thicker tunica media) ​ Veins: carry blood to the heart ​ define the terms elastic vessel, resistance vessel, capacitance vessel, and exchange vessel, Elastic arteries -​ Large artery, closest to heart -​ Aorta -​ Lots of elastic fibers (heart can expand and return) ​ Muscular arteries -​ Smaller arteries that supply organs -​ Lots of smooth muscle Capacitance vessel (small veins) -​ hold lots of circulating blood ​ Resistance vessel -​ Arterioles -​ Change in resistance to blood flow -​ Regulates blood flow and constriction/relaxation of blood vessels Exchange vessel  -​ Capillaries, move materials through the vessel wall -​ Thin wall (exchange of waste products and gases) -​ Arteriole (blood to capillaries) -​ Venule (capillaries to heart) ​ describe the function of a venous valve and consequences of valve failure Venous valve (veins): prevents backflow of blood, foldings of tunica intima Consequences (valve failure): varicose veins and hemorrhoids as a result of high venous pressure ​ describe the structure of each of the three types of capillaries and describe which size substance can move through each Continuous Capillaries -​ Least leaky, cells bound together with tight junctions -​ Allows small solutes and lipid-soluble substances to pass through -​ Blocks RBC and plasma -​ Forms the blood brain barrier Fenestrated Capillaries -​ Middle leakiness, small pores (fenestrations) -​ Allows water and larger solutes to pass through (rapid ​ Sinusoidal Capillaries -​ Most leaky, large gaps between endothelial cells -​ Allows free exchange of water and large plasma proteins ​ Explain precapillary sphincters and muscular pump Precapillary sphincters: regulate blood flow via the capillary bed, when relaxed (blood flow + exchange occurs), when contracted (blood flow and no exchange occurs) Muscular pump: contraction of skeletal muscle, veins compress, pushes blood back to the heart  ​ name the major veins leading into the heart and the main arteries leading away from the heart in both systemic and pulmonary circulations ​ Aorta: vessel that leaves the left side of the heart, aortic arch (curved), thoracic aorta (thoracic cavity) and abdominal aorta (below diaphragm) Systemic circuit: -​ Main vein (superior and inferior vena cava): returns blood from the body back to the heart -​ Main artery (aorta): brings blood from heart to body tissues Pulmonary circuit: -​ Main vein (pulmonary veins): bring blood from lungs back to the heart -​ Main artery (pulmonary artery): bring blood from heart back to lungs LECTURE 5 ​ describe the anatomical position of the heart in the body  The heart lies in the mediastinum, which is a chamber inside the thoracic cavity. The superior part of the heart is called the base and the inferior part is called the apex. ​ describe the structure of the heart wall Endocardium: innermost layer, endothelium Myocardium: middle layer, cardiac muscle Epicardium: outer layer, fat and connective tissue ​ ** heart is surrounded by pericardium, a connective tissue sac, the fibrous layer (outer layer) is rigid/dense and protects the heart, the serous layer (inner layer) helps to lubricate heart and reduce friction ​ Explain the concept of a pericardial cavity Pericardial cavity (serous membrane): fluid filled space, surrounds the heart Visceral pericardium/epicardium (inner surface): directly attaches to the heart Parietal pericardium (outer surface): reduces friction ​ name the coronary arteries and describe their locations and distributions  Coronary arteries supply oxygenated blood to the heart (coronary arteries and veins travel in grooves called sulci before entering heart wall) Right coronary artery: branches from aorta (right side), supplies the right atrium and both ventricles Left coronary artery: branches from aorta (left side), splits into two other arteries Left anterior descending: left front side of heart, supplies both ventricles in the front Circumflex artery: wraps around to the back, supplies posterior wall ​ describe the pattern of blood flow through the heart, including chambers, valves, and major vessels around the heart Right Side: -​ Blood enters right atrium via superior and inferior vena cava -​ Blood passes through tricuspid valve (open) to enter the right ventricle -​ Blood leaves right ventricle via pulmonary valve and enters pulmonary trunk  -​ Pulmonary trucks branches into right and left pulmonary arteries, carrying blood to the lungs ​ Left side: -​ Blood from lungs enters left atrium via pulmonary veins -​ Blood passes bicuspid valve to enter left ventricle -​ Blood leaves left ventricle to enter aorta via aortic valve -​ Blood ascends to aortic arch ​ Describe the concept of pressure pumps Right ventricle: -​ Thinner myocardium -​ Less pumping power -​ Supplies the lungs ​ Left ventricle: -​ Thicker myocardium -​ More pumping power  -​ Blood to the rest of the body ​ contrast the function of an AV valve with a semilunar valve AV valve: fibrous cusps attached to papillary muscles via chordae tendineae, hols cusps in place, open when atrial pressure is greater than ventricular pressure, regulate blood flow from atria to ventricles (tricuspid and bicuspid valves) Semilunar valves: no papillary muscles, open when ventricular pressure is higher than atrial pressure, regulate blood flow from the ventricles into the arteries (pulmonary and aortic valves) ​ describe the action potential of a pacemaker cell Pacemaker cells -​ Specialized cardiac cells -​ Found in SA and AV nodes -​ Distribute action potentials that simulate heartbeat -​ Autorhythmic, control center in medulla -​ Creates electrical signals ​ Action potential: -​ Pacemaker cells depolarize the cell (influx of calcium) until the threshold is reached, then an action potential is fired -​ Repolarization occurs when calcium channels close and potassium channels open ​ describe the sequence of information flow through the conduction system 1)​ SA node (triggers atrial contractile cells to contract) to AV node (slows impulse) 2)​ AV node to AV bundle (transmits electrical impulses) 3)​ AV bundle to bundle branches (carry electrical impulse to purkinje fibers) 4)​ Reaches purkinje fibers (causes ventricle walls to contract) ​ describe common disorders of the conduction system Pericardial effusion: fluid buildup within the pericardial cavity Cardiac tamponade: heart won’t fill will blood properly, heart compression Bradycardia: abnormally slow heart rate  Tachycardia: abnormally fast heart rate Heart murmur: abnormal sounds and blood movement, faulty valves Ectopic pacemaker: abnormal cells in chamber wall generate high rate of action potentials Treatment: pacemaker device helps to regulate abnormal heart activity LECTURE 6 ​ Describe pacemaker cells and the results of abnormal pacemaker function Pacemaker cells: -​ Spontaneously depolarize -​ Found in both SA and AV nodes -​ Generates action potentials (pacemaker potential = sodium influx, depolarization = calcium influx, repolarization = potassium efflux -​ No flat baseline/resting membrane potential (due to pacemaker potential) ​ Abnormalities (pacemaker used to regulate abnormal activity):  -​ Normal heart rate between 60-100 bpm -​ Bradycardia (100 bpm) -​ Ectopic pacemaker: abnormal cells in chamber, bypass normal conduction system ​ Explain the key events involving in pumping blood Gap junctions: cardiac cells are electrically synchronized Excitation-contraction coupling: increase in calcium, muscle contracts, sarcomere shortens Desmosomes: velcro, hold cells together ​ describe the structure and action potential of a contractile myocardial cell Contractile myocardial cell: -​ Small in size, has single nucleus -​ Sarcoplasmic reticulum releases calcium -​ Connected via intercalated discs -​ Stable resting membrane potential, unlike pacemaker cells ​ Calcium channel blockers: reduce calcium concentration, contract less forcefully (heart disease) ​ Action potential: -​ Depolarizing phase (sodium influx) -​ Plateau phase (calcium influx, potassium efflux) -​ Repolarization phase (potassium efflux) -​ Lasts as long as the contraction (long refractory period, prevents tetanus of cardiac muscle), gives heart enough time to pump blood effectively ​ describe the typical wave form of an ECG and explain the underlying events P wave: atrial depolarization QRS complex: ventricular depolarization T wave: ventricular repolarization  -​ Ventricular fibrillation (V-fib): total loss of electrical synchronization, may lead to cardiac arrest ​ describe the steps in the cardiac cycle, relating valve openings and closings to the pressure changes during the cycle Cardiac cycle: one cycle of heart beat 2 phases: systole (contraction of myocardium) and diastole (relaxation of myocardium) 1)​ SA node fires action potential 2)​ Spread to contractile cells in right/left atria (atrial systole) 3)​ Electrical signal transmitted through conduction system 4)​ Purkinje fibers generate action potentials in both left and right ventricles (ventricular systole = ventricles contracting, atrial diastole= atria relaxing, ventricular diastole = ventricles relax) ​ Ventricular systole: First phase: ventricles push AV valves closed Second phase: as ventricular pressure exceeds aortic pressure, the semilunar valves open and blood is released (ejected) ​ Ventricular diastole: First phase: ventricles relax, blood flows back against semilunar valves (forces them closed) Second phase: ventricles fill passively Pressure gradient: movement of blood from high to low pressure Open valve: blood can only move out if valve is open ​ Explain blood pressure, normal heart sounds and volume changes Blood pressure: pressure exerted by blood onto blood vessel wall Heart sounds: -​ First Sound (S1, lub): closing AV valves -​ Second Sound (S2, dub): closing semilunar valves Volume changes: EDV (end of diastole or filling in ventricles) ESV (end of systole in ventricles) LECTURE 7 ​ define cardiac output and describe its importance Left ventricle is stronger because it has to pump blood out of the aorta and to the rest of the body. Cardiac output: -​ amount of blood pumped by left ventricle in one minute -​ ml/minute -​ HR (heart rate) X stroke volume  -​ Determines how much blood and oxygen is available to the body tissues ​ relate cardiac output, heart rate, end diastolic volume, end systolic volume and stroke volume Heart rate (beats per minute): -​ Directly related to CO -​ Cardio control center in medulla (brainstem): acceleratory (release NE, increases heart rate), inhibitory (releases ACh, decrease heart rate) ​ End diastolic volume (directly related to stroke volume): -​ blood in ventricle after it has filled, just before contraction -​ More blood in ventricle before contraction (EDV), causes more blood to be pumped out (SV) ​ End systolic volume (inversely related to stroke volume): -​ Amount of blood left over in ventricle after contraction -​ More blood in the ventricles, less is being ejected, reduces stroke volume Stroke volume: amount pumped out of the left ventricle during systole ​ explain the regulation of heart rate by the autonomic nervous system ANS (contains medulla) -​ Cardiovascular controls centers that speed up and slow down heart rate -​ Parasympathetic fibers (SA and AV nodes): release ACh that binds to muscarinic receptors -​ Sympathetic fibers (SA and AV nodes): releases NE, binds to adrenergic receptors (beta 1) ​ Autonomic axons: adjust heart rate by slowing down/speeding up rate of spontaneous depolarization of pacemaker cells ​ explain the factors regulating stroke volume, defining preload, afterload, and contractility  Changing EDV affects stroke volume directly : 1)​ Filling time: duration of ventricular diastole 2)​ Venous return: rate of blood flow during ventricular diastole ​ Changing ESV affects stroke volume inversely 1)​ Preload: ventricle walls expand when filled with blood in diastole 2)​ Contractility: force produced during contraction 3)​ Afterload: pressure ventricle must need to overcome to open semilunar valves and eject blood ​ Increased preload (more blood filling ventricle, more stretch, greater contractions, increase in blood ejected (SV) ​ Increased contractility (decreases ESV and therefore increases stroke volume), decrease contractility = beta blockers block E/NE receptors, calcium channel blockers decrease calcium entry ​ Decreased afterload (pressure to eject blood is not very high, ventricles can easily eject blood and increase stroke volume), inversely related to ESV ​ explain ejection fraction as an important clinical measure of cardiac function Ejection Fraction: -​ % of EDV pumped out in one beat -​ SV/EDV x 100% -​ 50-75% (heart pumping is normal) ​ Explain sympathetic nervous system influence over vessel diameter Sympathetic tone (baseline for sympathetic activity) 1)​ Increased sympathetic activity = increased degree of constriction = reduced blood flow (vasoconstriction) 2)​ Decreased sympathetic activity = decreased degree of constriction = increased blood flow (vasodilation)