Blood Vessels and Circulation – Flashcards
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What are the 3 tunics of the vessel wall?
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Tunica interna, tunica media, tunica externa
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Which tunic of the vessel wall, line the inside of the vessel and is exposed to the blood?
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tunica interna
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Which tunic of the vessel wall consists of simple squamous epithelium (endothelium), overlying a basement membrane and a sparse layer of loose connective tissue?
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tunica interna
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What is the layer of the vessel that acts as a selectively permeable barrier to materials entering or leaving the bloodstream?
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Endothelium of tunica interna
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Which vessel layer secretes chemicals that stimulate dilation or constriction of the vessel; and normally repels blood cells and platelets so that they flow freely without sticking to the vessel wall?
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Endothelium if the tunica interna
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Which tunic is the middle layer?
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Tunica media
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Which tunic is usually the thickest?
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Tunica media
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Which vessel layer strengthens the vessel and prevents blood pressure from rupturing them, and regulates the diameter of the blood vessel?
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Tunica media
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Which tunic is the outermost layer?
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Tunica externa
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Which vessel layer anchors the vessel to adjacent tissues and provides passage for small nerves, lymphatic vessels, and smaller blood vessels that supply the tissues of the larger vessel?
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Tunica externa
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Which vessels are also called resistance vessels of the cardiovascular system because they have relatively strong, resilient tissue structure?
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Arteries
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Which vessels are more muscular, retain their round shape even when empty, and built to withstand pressure?
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Arteries
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What are the three classes of arteries?
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Conducting arteries, distributing arteries, resistance arteries
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Which arteries expand as they receive blood during ventricular systole, and recoil during diastole, reducing pressure off of the blood so that smaller arteries downstream are subject to less systolic stress?
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Conducting arteries
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The aorta, common carotid artery, subclavian arteries, pulmonary trunk, and common iliac arteries are examples of which class of arteries?
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Conducting arteries
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Which class of arteries are smaller branches that distribute blood to specific organs?
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Distributing arteries
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Brachial, femoral, renal and splenic arteries are examples of which class of arteries?
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Distributing arteries
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Which vessels are the efferent vessels of the cardiovascular system - that is, they carry blood away from the heart?
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Arteries
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Which vessels are afferent vessels of the cardiovascular system - that is, they carry blood back to the heart?
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Veins
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Which vessels are microscopic, thin-walled vessels that connect the smallest arteries to the smallest veins?
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Capillaries
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The smallest of the resistance arteries are called?
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Arterioles
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Which vessels have very little tunica externa, and are a major point of control over how much blood an organ or tissue receives?
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Arterioles
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Which vessels are sometimes called exchange vessels of the cardiovascular system?
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Capillaries
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Which vessels are known as the capacitance vessels of the cardiovascular system?
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Veins
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Which vessels are thin-walled and flaccid, and expand easily to accommodate an increased volume of blood.
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Veins
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Which vessels are the smallest of veins and receive blood from the capillaries directly?
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Postcapillary venules
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Low pressure vessels.
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Veins
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High pressure vessels.
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Arteries
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Which vessels have steady blood flow?
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Veins
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Which vessels have pulsating blood flow?
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Arteries
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The five mechanisms involved in venous return are?
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Pressure gradient, gravity, the skeletal muscle pump, the thoracic (respiratory) pump, and cardiac suction.
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Vasodilation and constriction are collectively called?
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Vasoreflexes
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Two physiological purposes vasoreflexes serve are?
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Raising or lowering blood pressure throughout the body, and selectively modifying the perfusion of a particular organ and rerouting blood from one region to another.
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Vasoreflexes are facilitated by?
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hormones or the autonomic nervous system or occur in direct response to the local metabolic state of a tissue.
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What contracts during vasoconstriction?
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the smooth muscle of the tunica media.
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When muscular passivity occurs in a blood vessel, relaxation of the smooth muscle allows blood pressure to expand the vessel, this is known as?
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Vasodilation
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The resistance of a fluid to flow, resulting from the cohesion of its particles
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Viscosity
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Reduced blood viscosity causes blood flow to?
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Increase
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Increased blood viscosity causes blood flow to?
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Decrease
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The most significant factors that affect blood viscosity are?
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erythrocyte count and albumin concentration
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Three ways of controlling vasomotor activity?
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local, neural, and hormonal mechanisms
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During vigorous exercise, what do the arteries in the lungs, coronary circulation and muscles do?
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Dilate
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During vigorous exercise, what do the arteries in the kidneys and digestive tract do?
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Constrict
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The opposition to flow that the blood encounters in vessels away from the heart.
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Peripheral resistance
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Peripheral resistance depends on these 3 variables.
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Blood viscosity, vessel length, and vessel radius
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What do pressure and flow do with distance?
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Decline
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The physical force exerted by a liquid against a surface such as a capillary wall is called?
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Hydrostatic pressure
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The portion of osmotic pressure due to protein is called?
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Colloid osmotic pressure
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The difference between the colloid osmotic pressure and tissue fluid is called?
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oncotic pressure
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Positive hydrostatic pressure within a capillary and negative interstitial pressure work in the same direction, this draws fluid?
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Out of the capillaries
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The higher colloid osmotic pressure in blood versus tissue fluid causes fluid to?
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be drawn into the capillary by osmosis
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Name the vessels of the pulmonary circuit.
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Pulmonary trunk, pulmonary arteries, superior lobar artery, middle lobar artery, inferior lobar artery, pulmonary veins
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Where does blood unload CO2 and pick up O2?
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Capillary beds and alveoli in the lungs
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What is the purpose of the pulmonary circuit?
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Exchange CO2 for O2
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What are the first 3 major branches off of the aorta?
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Brachiocephalic trunk, left common carotid, left subclavian
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Which circuit supplies oxygen and nutrients to all organs and removes their metabolic wastes?
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Systemic
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Which circuits purpose is primarily to exchange CO2 for O2?
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Pulmonary
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Which tunic is usually the thickest?
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Tunica Media