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58 Cards in this Set
- Front
- Back
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What is the most common circulatory route?
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Heart->arteries->arterioles->capillaries->venules->veins
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How many capillary networks does blood pass through before returning to the heart?
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Two
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What is a anastomoses?
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When two arteries or veins merge together.
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What is a ateriovenous shunt?
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When an artery connects directly to a vein.
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What is a venous anastomosis?
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When two veins merge.
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What is arterial anastomosis?
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Alternative routes of blood flow, common around joints.
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What are the three levels of the vessel wall?
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Tunica externa, tunica media, tunica interna.
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What are some features of the tunica externa?
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Outside most layer, loose connective tissue, provides passage for other bv, nerve, and lymphatic vessels.
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What are some features of the tunica media?
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Thickest middle layer, smooth muscle, collagen.
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What are some features of the Tunica interna?
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Thin inner layer, exposed to blood, simple squamos endothelium.
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What are the vaso vasorum?
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Small vessels that supply blood to the tunica externa of large blood vessels.
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What are conducting (elastic) arteries?
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Thickest kind of artery, elastic tissue.
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What are some examples of a conducting artery?
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Aorta, common carotid.
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What are distributing (muscular) arteries?
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Distribute blood to specific organs, smooth muscle.
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What are some examples of distributing arteries?
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Brachial artery, femoral artery.
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What are resistance (small) arteries?
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Are arteries or arterioles, they control the amount of blood to various organs, elastic and smooth muscle.
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What are capillaries?
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The point of exchange between blood and tissues.
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What's the furthest away a tissue can be from capillaries?
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20 cell layers.
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Where are there no capillaries?
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Cartilage, cornea, and lens.
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Where are capillaries scarce?
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Tendons and ligaments.
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What are capillary beds?
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Groups of 10-100 capillaries.
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What are metaterioles?
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Short vessels that connect arterioles, capillaries, and veins through a capillary network.
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What is a throughfare channel?
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When a metarteriole continues through a capillary bed and leads directly into a venule.
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How many capillaries are open at any given time?
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1/4
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What is a continuous capillary?
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The kind that occur in most tissues, endothelial cells have tight junctions with intercellular clefts.
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What are fenestrated capillaries?
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When the endothelial cells have filtration pores called fenestrations.
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What do fenestrations do?
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Allowed more rapid passage of small molecules.
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Where are fenestrated capillaries found?
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In organs that require rapid absorption or filtration, like the kidneys, small intestine.
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What are sinusoids capillaries?
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Irregular blood-filled spaces.
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What do sinusoids capillaries do and where are they found?
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Allow proteins and blood cells to enter, found in liver, bone marrow, spleen.
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What are venous sinuses?
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Veins with thin walls, large lumens, and no smooth muscle.
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What do venous valves aid in?
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They aid skeletal muscles with upward flow.
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What are venous valves like?
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Semilunar valves, blood flows backwards and closes cusps.
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Where are venous valves found?
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In the arms and legs
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How are vericose veins formed?
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From problems with venous valves.
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What are some causes of vericose veins?
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Standing for long periods of time, obesity, pregnancy, genetics.
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How is blood pressure measured?
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By a sphygmomanometer at the brachial artery.
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What is systolic pressure?
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Peak BP during ventricular systole.
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What is diastolic pressure?
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The minimum BP between heartbeats.
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What is a 'normal' BP for young adults?
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120/75
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What is mean arterial pressure (MAP)?
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Measurements of BP taken at intervals of cardiac cycle.
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What is hypertension?
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Chronic elevated resting BP
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What is hypotension?
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Chronic low resting BP.
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What are some causes of primary hypertension?
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Obesity, being sedentary, diet, nicotine, genetics.
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WHat are aneurysms?
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Weak points in a blood vessel or heart wall.
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What are some causes of aneurysms?
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Hypertension, atherosclerosis, trauma, bacterial infections.
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What is a dissecting aneurysm?
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When blood pools between tunics causing degeneration of the tunica media.
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What are three things that effect peripheral resistance of blood?
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Blood viscosity, vessel length, vessel radius.
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When does the flow of blood decrease?
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From the aorta to capillaries.
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What are three reasons blood flow decreases from the aorta to the capillaries?
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Greater distance traveled, smaller radii of capillaries, further from heart, greater cross sectional area.
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When does the flow of blood increase?
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From the capillaries to the vena cava
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What are four ways blood flow is controlled locally?
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Tissue metabolism, vasoactive chemicals, reactive hyperemia, angiogenesis.
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How is the flow of blood controlled neurally?
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Through the vasomotor center in the medulla oblongata.
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What is reactive hyperemia?
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When blood flow is cut off then restored.
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What is angiogenesis?
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The growth of new blood vessels.
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What are three ways that the neural center controls blood flow?
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Through baroreflexes, chemoreflexes, and medullary ischemic reflex.
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What are baroreflexes?
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Changes in BP detected by stretch receptors (baroreceptors) in large arteries above the heart.
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What are chemoreflexes?
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Autonomic response to changes in blood chemistry.
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