Chapter 19

24 July 2022
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question
Which layer of the typical blood vessel is constructed from simple squamous epithelium? tunica externa tunica intima tunica media
answer
Tunica intima The tunic intima of blood vessels, like the endocardium of the heart, is made of simple squamous epithelium.
question
Which layer of the typical vessel can be regulated to constrict or dilate the lumen? tunica externa vasa vasorum tunica intima tunica media .
answer
Tunica media The tunica media consists of smooth muscle that is regulated by the sympathetic nervous system. It is used to regulate the diameter of the lumen
question
Which type of vessel is most suited to expanding and recoiling in response to the ejection of blood from the heart? muscular artery large veins arteriole elastic artery
answer
Elastic artery Elastic arteries absorb most of the shock when the heart ejects blood. The expansion stores energy; the recoil disperses this energy by moving blood further through the circulation.
question
What type of vessel has a relatively large amount of smooth muscle compared to its elastic tissue? capillary arteriole elastic artery muscular artery
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muscular artery Muscular (distributing) arteries have relatively thick muscle layers with little elastic support. They are designed to distribute blood and control flow.
question
What type of vessel is capable of allowing the passage of gases and nutrients though its walls to nourish surrounding tissue? venules small veins capillaries arterioles
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capillaries The thin walls of capillaries allow gases and nutrients to be exchange freely with surrounding cells.
question
Arteries always carry oxygenated blood away from the heart. True False
answer
False Arteries always carry blood away from the heart. However, blood in the pulmonary circuit is the opposite of what we might expect. Blood carried away from the heart and to the lungs is deoxygenated.
question
Which vessels carry blood toward the heart? venules veins arteries capillaries
answer
Vein Veins carry blood to the heart.
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Which of the following is characteristic of veins but not arteries? elastic membranes vasa vasorum large muscular tunic larger internal diameter
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larger internal diameter Veins have larger internal diameters than similar sized arteries.
question
Large diameter, thick-walled arteries that are close to the heart and act as pressure reservoirs would be __________. veins muscular arteries elastic arteries arterioles
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Elastic arteries Elastic arteries are thick-walled arteries near the heart. These arteries are the largest in diameter. Elastic arteries act as pressure reservoirs; they expand and contract as blood is ejected from the heart.
question
Continuous capillaries are the most common capillaries in the body. True False
answer
True Continuous capillaries are the most common capillaries. Fenestrated capillaries are found only in in sites of filtration of absorption. Sinusoidal capillaries are limited to a few organs, like the spleen, bone marrow, liver, and adrenal medulla.
question
The most permeable capillaries, which contain fenestrations and large intercellular clefts, are __________. continuous capillaries arterioles fenestrated capillaries sinusoidal capillaries
answer
sinusoidal capillaries Sinusoidal capillaries are the most permeable type of capillary due to large intercellular clefts among their endothelial cells. These capillaries allow large molecules--even blood cells--to pass into the surrounding tissue. Sinusoidal capillaries are found in the liver, bone marrow, spleen, and adrenal medulla.
question
The kidneys filter the blood; it is necessary for plasma, both fluid and dissolved chemicals, to be rapidly removed from the blood without the removal of larger proteins or cells. Which capillary would be best suited for this filtration? anastomoses sinusoids continuous capillaries fenestrated capillaries
answer
fenestrated capillaries Fenestrated capillaries are found wherever active capillary absorption or filtrate formation occurs.
question
Which of the following is true about veins? Veins have a smaller diameter lumen than arteries. Veins are more muscular than arteries. Veins carry blood away from the heart, while arteries carry blood to the heart. Veins have valves; arteries do not.
answer
Veins have valves; arteries do not. Veins have valves; arteries do not. Veins have valves to prevent the backflow of blood.
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Which of the following is mismatched? veins: resistance vessels elastic arteries: conducting vessels capillaries: exchange vessels muscular arteries: distribution vessels
answer
veins: resistance vessels veins have relatively large diameters; large diameter vessels reduce resistance
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Which of the following is NOT an important source of resistance to blood flow? vessel diameter blood viscosity vessel length total blood volume
answer
total blood volume Total blood volume is not an important source of resistance to blood flow. However, blood volume does have a direct effect on blood pressure.
question
What blood vessel experiences the steepest drop in blood pressure? arteries arterioles venules capillaries
answer
aterioles Arterioles have the greatest resistance to blood flow and therefore produce the greatest drop in pressure.
question
What vessels sustain a drop in pressure from approximately 35 mm Hg to around 17 mm Hg? veins capillaries elastic arteries arterioles
answer
capillaries 35 mm Hg and 17 mm Hg are typical entering and exiting pressures for a capillary bed. These pressures strongly affect the exchange of fluids across the capillary wall.
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At what point would we definitely NOT be able to measure the difference between systolic, diastolic, and mean arterial pressure? capillaries muscular arteries arterioles elastic arteries
answer
capillaries By the time blood reaches the capillaries, the pulsatile pressure differences would be unnoticeable.
question
Which tunic of an artery is most responsible for maintaining blood pressure and continuous blood circulation? tunica media tunica intima tunica adventitia tunica externa
answer
tunica media
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Which statement best describes arteries? Only large arteries are lined with endothelium. All carry oxygenated blood to the heart. All carry blood away from the heart. All contain valves to prevent the backflow of blood.
answer
all carry blood away from the heart
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The arteries that are also called distributing arteries are the ________. capillaries arterioles muscular arteries elastic arteries
answer
muscular arteries
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Due to the branching of arteries the type of arteries that would be most numerous would be ________. muscular arteries elastic arteries pulmonary arteries arterioles
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arterioles
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Site where resistance to blood flow is greatest
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Arterioles
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Site where exchanges of food and gases are made
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Capillaries
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Site where blood pressure is lowest
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Large veins
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Site where the velocity of blood is fastest
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Large arteries
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Site where the velocity of blood is the slowest
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Capillaries
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Site where the blood volume is greatest
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Large veins
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Site where the blood pressure is greatest
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Large arteries
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Site that is the major determinant of peripheral resistance
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Arterioles
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Factors that aid venous return include all except ________. urinary output activity of skeletal muscles venous valves pressure changes in the thorax
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urinary output
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A precapillary sphincter is a cuff of smooth muscle that regulates the flow of blood into the capillaries. True False
answer
True
question
The influence of blood vessel diameter on peripheral resistance is ________. significant because resistance is inversely proportional to the fourth power of the vessel radius significant because resistance is directly proportional to the blood vessel diameter insignificant because vessel diameter does not vary the only factor that influences resistance
answer
significant because resistance is inversely proportional to the fourth power of the vessel radius
question
The pulse pressure is ________. systolic pressure plus diastolic pressure systolic pressure divided by diastolic pressure systolic pressure minus diastolic pressure diastolic pressure plus 1/3 (systolic pressure plus diastolic pressure)
answer
systolic pressure minus diastolic pressure
question
The outermost layer of a blood vessel is the tunica intima. True False
answer
False