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Anatomy Final Review GuideCumulative Material Cardiovascular System & Blood Vessels- Anatomy of the Hearto Pulmonary Circuit: right side of heart, supplies blood to lungs for gas exchange Right atria, AV (tricuspid) valve, right ventricle, semilunar valve, pulmonary arterieso Systemic Circuit: left side of heart, supplies blood to body  Left atria, bicuspid valve, left ventricle, semilunar valve, aortao Pericardium Sac-like, double-walled structure wrapped around heart Allows heart to beat without friction, can expand but resists excessive expansiono Myocardium 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 muscleso Valves AV valves:connect atria and ventricles- Right: tricuspid, left: bicuspid Semilunar: control flow into great arteries- Right: pulmonary, left: aortic- Ventricular pressure controls valve movementoVentricles relax: ventricular pressure drops, semilunar valves close, AV valves open Blood flows from atria to ventriclesoVentricles contract: ventricular pressure rises, blood pushes AV valves closed, semilunar valves forced open, blood flows into pulmonary trunk and aorta- Anatomy of Blood Vesselso Tunica interna: single layer of endothelium, facing inward contacting blood Capillaries consist of single layer of tunica internao Tunica media: middle, thickest layer of vessel wall Consists of smooth muscle, collagen, and elastic tissue Smooth muscle controls vasomotiono Arteries 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 diastoleoDampens fluctuations b/w systole and diastole to maintain BP Small arteries: vary in size and number throughout body- Arterioles: control amount of blood to organsoGreatest amount of smooth muscle, little elastic tissue Metarterioles: short vessels connecting arterioles to capillaries Arterial sense organs: - Baroreceptors: in aortic arch and carotid sinusoMonitor BP: signals cardiac and vasomotor centers in medulla if BP increases Trigger decrease in HR and vasodilation- Chemoreceptors: located in carotid and aortic bodiesoMonitor changes in blood chemistry: adjust breathing rate to stabilize blood pH, CO2, and O2o Capillaries 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 poresoAllow for rapid passage of small molecules, increasing rate of exchangeoFound 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- Precapillary sphincter: control which beds are perfused with bloodo¾ of capillaries shut down at given time depending on activityo Veins 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 Venules:- Postcapillary venules exchange fluid w/ tissues, lead to muscular venules Large veins: venae cavae, pulmonary veins- Contain some smooth muscle in all three layers- Circulationo Common 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:- Long-term obstruction of coronary circulation causes death of cardiac cellso Portal system: 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 veino Capillary 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 forcesoHydrostatic 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 decreaseoColloid 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 endoHP 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 reabsorptiono Edema Accumulation of excess fluid in tissue- Three fundamental causes: increased filtration, reduced reabsorption and blockage of lymph Systemic edema:

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NU BIOL 1121 - Final Review Guide

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