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Questions from Tuesday granules function similar to lysosomes − contain proteins/enzymes that kill ingested bacteria, fungi, viruses − responsible for the green color of pus histamines and MS − myeloid vs. myelin − blocking certain histamine receptors reduced symptoms of MS-like disease in mice myelos- Greek for marrow RBCs do not have DNA, do have RNA negative feedback − − feedback causes the stimulus to decline calcitonin and PTH each are a feedback system, the hormones have antagonistic effects questions 34, 45, 62a, 62c Chapter 11: Heart Physiology Heart Dysfunctions pericarditis - inflammation of pericardium − incompetent valve - does not close properly valvular stenosis - valve stiffening due to bacterial infection − decrease in amount of serous fluid in pericardial cavity both cause increased workload in heart angina pectoris - myocardium deprived of O2 − − if prolonged, ischemic heart cells die = infarct myocardial infarction or heart attack Cardiac Muscle cardiac muscle can contract spontaneously & independently needs control system to regulate Heart Activity regulation by two systems: − intrinsic conduction system (nodal system) − sets basic rhythm neural controls (ANS) increase or decrease heart rate Nodal System special nervous/muscle tissue causes one way heart muscle depolarization: atria to ventricles − contraction rate of 75 bpm sinoatrial node − − most important right atrium Nodal System Sinoatrial node highest rate of depolarization − pacemaker SA node -> atria -> pause* -> AV node -> bundle branches -> Purkinje fibers *lets the atria contract before the ventricles Heart Rate Dysfunctions damage to the SA node = slower heart rate − ischemia (inadequate blood supply) of the myocardium can lead to fibrillation − − artificial pacemaker uncoordinated contractions defibrillator - depolarizes heart to let natural pacemaker to reestablish normal rhythm tachycardia-rapid heart beat (>100 bpm) bradycardia-slow heart beat (< 60 bpm) Cardiac Cycle systole - contraction of ventricles diastole - relaxation of ventricles cycle = 1 complete heartbeat − − − mid-to-late diastole ventricular systole early diastole Cardiac Cycle mid-to-late diastole − − − − − complete relaxation low pressure = passive blood flow at end, atria contract which valves open? which valves closed? Cardiac Cycle Cardiac Cycle ventricular systole − − − − ventricles contract increased pressure atria are relaxed which valves open & closed? Cardiac Cycle Cardiac Cycle early diastole − − − ventricles relax atria filling with blood which valves open & closed? Cardiac Cycle Cardiac Cycle Heart Sounds “lub dup…lub dup…lub dup…” sounds come from what? − − lub = closing of AV valves dup = semilunar valves close at end of systole heart murmur - valve problems Cardiac Output CO = amount of blood pumped out by each ventricle in one minute CO = heart rate (HR) X stroke volume (SV) − SV = volume of blood pumped by each ventricle each beat What is CO if HR is 75 bpm and SV is 70 ml/beat =5250 ml/min Regulation of Stroke Volume how much cardiac muscle cells are stretched before contraction − stretch relies on venous return − more stretch = stronger contraction amount of blood distending the ventricles increase in volume or speed of venous return also increases stroke volume get up and jog in place for 1 minute Basic Heart Rate (HR) control of heart rate by ANS sympathetic can increase HR − parasympathetic slow and steady HR − more O2 and glucose available to cells vagus nerve epinephrine & thyroxine increase HR ion excess or deficit (Ca2+, Na+, K+) can change heart activity Basic Heart Rate epinephrine & thyroxine increase HR ion excess or deficit (Ca2+, Na+, K+) can change heart activity age, gender, exercise, body temp Heart Dysfunctions congestive heart failure - heart cannot meet tissue circulation needs − coronary artherosclerosis − clogging of coronary arteries high bp Blood Vessels: General functions moves blood, plasma transports hormones, nutrients, gases helps the transport of lipids Blood Vessels arteries - move blood away from the heart capillary beds - gas exchange occurs veins - return blood to heart Blood Vessels • tunica intima • tunica media - smooth muscle & elastic tissue • tunica externa - fibrous connective tissue Arteries vs. Veins artery walls thicker than veins − − − tunica media is heavier close to heart arteries must expand and recoil so walls are strong and stretchy Arteries vs. Veins veins − − − muscular pump − far from heart low pressure valves contraction respiratory pump − inhale = drop in thoracic pressure Capillaries walls one cell layer thick − − only tunica intima gas exchange networks are called beds vascular shunt true capillaries Capillaries precapillary sphincter − − acts as valve regulates blood flow Cardiovascular Physiology arterial pulse − from what? blood pressure − − higher closer or further away from heart? keeps blood circulating continuously Blood Pressure highest in large arteries lowest in venae cavae − muscular pump & respiratory pump are important for venous return what happens if you cut a vein? an artery? Blood Pressure elastic artery walls help keep continuous blood flow arteriosclerosis = hardening of artery walls can lead to hypertension, or high blood pressure − why? Measuring Blood Pressure rises & falls each beat − − systolic: pressure at ventricular contraction diastolic: pressure at ventricular relaxation auscultatory method Blood Pressure remember CO = HR X SV blood pressure, BP = CO X PR PR is peripheral resistance = amount of friction blood encounters in the vessels any changes in CO or PR affects BP Blood Pressure sympathetic nervous system − kidneys − − cold = constrict heat = dilate chemicals − − alter blood volume in response to blood pressure temperature − vasoconstriction: narrowing of vessels epinephrine alcohol diet Blood Pressure 110-140 mmHg systole / 75-80 mmHg diastole hypotension = BP <100 mmHg systolic − − physical conditioning chronic - poor nutrition, low blood proteins orthostatic hypotension - dizziness upon rising in the elderly − aging sympathetic nervous system reacts slowly to postural change Blood Pressure hypertension - 140/90 mmHg sustained strains heart, damages arteries diet, obesity, heredity, race, stress Capillary Exchange capillaries deliver gases and nutrients to all body cells how do substances move with respect to their concentration? oxygen and nutrients carbon dioxide, other wastes Capillary Exchange Four routes from endothelial cells of capillary wall to interstitial fluid − diffuse directly across plasma membranes − what kind of substances can do this? endocytosis or exocytosis Capillary Exchange intercellular clefts − − gap in plasma membrane all cells BUT brain cells fenestrated capillaries - (fenestra = window) − − free passage of small solutes and fluids absorption or filtration is important intestines, endocrine glands, kidneys Capillary Fluid Transport leaky clefts and fenestrations blood pressure forces fluid outward − arterial end of cap bed osmotic pressure draws fluid back in − − blood vs. interstitial fluid venous end of cap bed Capillary Fluid Transport Lab Ex. 21 - All activities − Ex. 22 - Activities 1-4 − vein, artery, capillary slide on a microscope up front if time Act. 5-6 Turn in on Tuesday: − − − Review sheets 21 & 22 on pp. 327-338 Ex. 22 pp 195-197 Ex. 22 pp 198-200, if time