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25 Cards in this Set
- Front
- Back
Why does countercurrent exchange optimize gas exchange across some gills? |
It sustains an optimal respiratory gas concentration gradient, allowing diffusion to occur across the entire respiratory surface |
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When the body experiences stress, the sympathetic division of the autonomic nervous system stimulates the adrenal medulla to release |
epinephrine and norepinephrine |
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During resting breathing in humans, which of the following is accurate? |
Rib muscles and the diaphragm relax |
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The main force that moves blood throughout the system of blood vessels is |
arterial blood pressure |
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Which of the following respiratory surface properties enhances the diffusion of respiratory gases? |
large surface area |
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Which two components of blood involve the formation of clots? |
fibrinogen and platelets |
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What would you predict would happen in an area of the body where blood is relatively acidic (low pH)? |
O2 would release from hemoglobin |
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The purpose(s) of the pulmonary circuit in a closed circulatory system is to |
take blood to and from the lungs |
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Why is proper ventilation important for a respiring animal? |
It maintains proper O2 and CO2 levels on the external side of the respiratory surface so diffusion across it can be maintained |
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An atrioventricular valve would be located |
between the left atrium and the left ventricle, and between the right atrium and the right ventricle |
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Which of the choices below illustrates the control of cardiac output? |
baroreceptors-brainstem-heart |
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Which of the following would NOT be likely to pass easily through capillary walls? |
erythrocytes |
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CO2 is transported in the blood in which of the following? |
dissolved in the red blood cells exclusively |
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Which of the following is an example of local control over breathing? |
automated lung ventilation and lung perfusion adjustments maximizing O2 and CO2 exchange |
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Which of the following occurs during human inhalation? |
The diaphragm contracts and the external intercostal muscles contract |
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Where are baroreceptors located? |
walls of blood vessels |
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Which of the following chemicals has the LEAST influence on the regulation of breathing rate? |
O2 |
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The function of the valves in the heart is to |
prevent backflow of blood |
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Which structure(s) could be considered to be blood reservoirs? |
veins |
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Erythropoietin, a hormone that stimulates stem cells in the bone marrow to increase erythrocyte production, is produced in the |
kidneys |
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When blood returns from the pulmonary circuit, it first enters which chamber of the heart? |
left atrium |
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While running |
only your systolic blood pressure would elevate |
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The "lub" heart sound represents |
closure of the AV valves |
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Traveling to a high altitude can result in "altitude sickness." However, the body eventually adjusts through which mechanism? |
increased hemoglobin production as a result of increased secretion of erythropoietin |
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Which of the following is an advantage of water as a respiratory medium? |
Water keeps the respiratory surface wetted |