Anatomy Final Review Guide Cumulative Material Cardiovascular System Blood Vessels Anatomy of the Heart oPulmonary Circuit right side of heart supplies blood to lungs for gas exchange Right atria AV tricuspid valve right ventricle semilunar valve pulmonary arteries oSystemic Circuit left side of heart supplies blood to body Left atria bicuspid valve left ventricle semilunar valve aorta oPericardium Sac like double walled structure wrapped around heart Allows heart to beat without friction can expand but resists excessive expansion oMyocardium Thick layer of muscle Left side has thicker layer because it does more work but does NOT eject more blood Fibrous Skeleton network of elastic and cartilaginous fibers Provides structural support and attachment for cardiac muscle Electrical nonconductor helps coordinate contractile ability Interventricular septum divides left and right ventricles Interatrial septum divides left and right atria Chordae tendinae help prevent backflipping of valves connect valves to papillary muscles oValves AV valves connect atria and ventricles Right tricuspid left bicuspid Semilunar control flow into great arteries Right pulmonary left aortic Ventricular pressure controls valve movement oVentricles relax ventricular pressure drops semilunar valves close AV valves open Blood flows from atria to ventricles oVentricles contract ventricular pressure rises blood pushes AV valves closed semilunar valves forced open blood flows into pulmonary trunk and aorta Anatomy of Blood Vessels oTunica interna single layer of endothelium facing inward contacting blood Capillaries consist of single layer of tunica interna oTunica media middle thickest layer of vessel wall Consists of smooth muscle collagen and elastic tissue Smooth muscle controls vasomotion oArteries Relatively strong structure to resist blood pressure Conducting elastic arteries largest pul trunk aorta carotid subclaviac common iliac Smaller percentage of smooth muscle more elastic tissue oControlled expansion during systole recoil during diastole oDampens fluctuations b w systole and diastole to maintain BP Small arteries vary in size and number throughout body Arterioles control amount of blood to organs oGreatest amount of smooth muscle little elastic tissue Metarterioles short vessels connecting arterioles to capillaries Arterial sense organs Baroreceptors in aortic arch and carotid sinus oMonitor BP signals cardiac and vasomotor centers in medulla if BP increases Trigger decrease in HR and vasodilation Chemoreceptors located in carotid and aortic bodies oMonitor changes in blood chemistry adjust breathing rate to stabilize blood pH CO2 and O2 oCapillaries Composed only of endothelium with basal lamina and basement membrane Continuous most common occur in most tissues endothelial cells have tight junctions forming a continuous tube with intercellular clefts allow small molecules to pass through but block large proteins and blood cells Fenestrated Endothelial cells have many holes called filtration pores oAllow for rapid passage of small molecules increasing rate of exchange oFound in kidneys and small intestine Sinusoids irregular blood filled spaces in liver bone marrow spleen no basal lamina which normally stops movement of large molecules through fenestration allows proteins to pass through some allow for RBCs also Arranged into capillary beds supplied by a single metarteriole which passes through center to venule oVeins Venules Precapillary sphincter control which beds are perfused with blood o of capillaries shut down at given time depending on activity Expand easily w thinner walls due to distance from ventricles lower BP More constant BP in veins than arteries and collapse when empty Contain valves that open in only direction only to prevent backflow of blood Postcapillary venules exchange fluid w tissues lead to muscular venules Large veins venae cavae pulmonary veins Contain some smooth muscle in all three layers Circulation oCommon circulatory route Heart arteries arterioles capillaries venules veins Angina pectoris partial obstruction of coronary blood flow reversible ischemia or temporary lack of blood flow to cardiac muscle Myocardial Infarction oPortal system Long term obstruction of coronary circulation causes death of cardiac cells Blood flows through two consecutive capillary networks before returning to heart Seen in hypothalamus to ant pituitary kidneys b w intestines and liver Anastomoses shunt point where two blood vessels merge Arteriovenous anastomosis artery flows directly into vein oCapillary Exchange Change occurs across capillary wall b w blood and tissue fluid Chemicals can pass through Endothelial plasma membrane intercellular clefts or fenestrations Diffusion Most important mechanism of exchange moves nutrients and waste products Lipid soluble substances steroid hormones O2 CO2 pass through easily Glucose and electrolytes must pass through channels clefts or fenestrations Large particles like proteins held back except in sinusoids Filtration and Reabsorption Hydrostatic and colloid osmotic pressure COP are opposing forces oHydrostatic pressure drives fluid out of capillary Arterial end positive BP inside cap and negative interstitial pressure create net outward hydrostatic pressure Venous end positive BP inside cap negative interstitial pressure drives blood into cap BP drops as you move along capillary causing HP to decrease oColloid osmotic pressure COP due to diffusion of water due to conc of nonpenetrating solutes mainly protein more conc in blood than tissue Oncotic pressure net COP blood COP tissue COP Net COP same at both ends Net filtration at arterial end water pushes out into tissue Net reabsorption at venous end oHP is greater than constant COP at arterial end but less at venous end Capillaries reabsorb about 85 of fluid other 15 reabsorbed by lymph In resting tissue reabsorption predominates In metabolically active tissue filtration dominates Kidneys net filtration lungs net reabsorption Three fundamental causes increased filtration reduced reabsorption and blockage of Pressure build up in systemic capillaries increased fluid forced into tissues oEdema Accumulation of excess fluid in tissue lymph Systemic edema failure of right ventricle Can cause circulatory shock Pulmonary edema failure of left ventricle Can cause suffocation oVenous Return Pressure builds up in pulmonary capillaries increased fluid forced into lung tissues Pressure gradient pressure greater in