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A&P Ch 20 HW
Question | Answer |
---|---|
Resistance in the blood vessels is primarily controlled by altering | vessel radius. |
When carbon dioxide accumulates in a tissue, local arterioles will _________, increasing perfusion and decreasing carbon dioxide levels. | dilate |
Capillaries have only a | tunica intima. |
Under the microscope, the wall of a blood vessel is observed to contain only a tunica intima. This must be a(n) | capillary. |
The vessels that are responsible for carrying blood away from the heart are | arteries. |
In both pulmonary and systemic circulation, gas exchange occurs at the | capillaries. |
During exercise, blood is shifted from the __________ into systemic circulation. | Veins |
T/F : During exercise, resistance to flow in the viscera and organs decreases, causing an increase in blood flow to these areas. | False |
T/F :During exercise, resistance to flow in skeletal muscles increases. | False |
T/F : The changes in resistance to flow in the viscera and organs help cause an increase in blood flow to the skeletal muscles. | True |
T/F : Total cardiac output increases, but stroke volume always remains the same | False |
T/F : Capillary exchange is the process by which cells receive everything they need to survive and to eliminate metabolic waste. | True |
T/F : By far the most important means by which capillary exchange occurs is filtration | False |
T/F : A small amount of fluid moves out of capillaries at their venous ends, and most of that fluid reenters the capillaries at their arterial ends. | False |
T/F : Filtration pressure is the force responsible for moving fluid across capillary walls | True |
Vasomotion of the renal arteries will control blood flow to the | kidneys |
Blood pressure is highest in the ___________ and lowest in the _____________. | arteries closest to the heart; veins |
Under the microscope, a blood vessel is observed to have a relatively thin wall, a large lumen, is collapsed, and contains a thick tunica externa. This is probably a(n) | vein. |
Which vessel drains capillaries? | Postcapillary venules |
When a person changes position from lying down to standing, the blood pressure in the veins of the lower limbs __________. | increases |
In a working tissue like skeletal muscle, carbon dioxide may accumulate along with an increase in lactic acid. In this example, carbon dioxide and lactic acid will act as | vasodilators. |
Vasodilation | increases blood flow and decreases blood pressure. |
Vasoconstriction | decreases blood flow and increases blood pressure. |
T/F : Blood pressure is directly proportional to vessel resistance. | True |
T/F : Blood flow is affected by both blood pressure and vessel resistance. | True |
Deoxygenated blood from the heart myocardium drains into the right atrium via the | Coronary Sinus |