Which of the following statements concerning control of blood flow through arterioles is TRUE?
A. Beta-adrenergic receptors are more abundant on most arteriolar smooth muscle than are alpha-adrenergic receptors.
B. Binding of epinephrine to alpha-adrenergic receptors causes vasodilation.
C. Increased stimulation of vascular smooth muscle by the parasympathetic nervous system causes increased vasoconstriction.
D. If the arterial blood pressure to an organ suddenly decreases, arterioles in the organ will dilate in response.
E. Body-wide constriction of arterioles results in a decrease in the total peripheral resistance (TPR).
D
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Select the correct statement about proteins.
A) Strict vegetarians need not worry about adequate protein intake, as most vegetables are almost perfect sources of amino acids. B) Proteins can be synthesized in the body if most of the amino acids are present. C) Proteins will be used by most cells for ATP synthesis if insufficient carbohydrates are ingested. D) Catabolic steroids (hormones) accelerate the
Smooth muscles relax when intracellular Ca2+ levels drop but may not cease contractions
Indicate whether the statement is true or false
The condition acute respiratory distress syndrome (ARDS) is characterized by damage to the respiratory membrane that causes it to thicken. What effect will this thickening have on the pulmonary gas exchange?
a) It would increase external gas exchange because thickness would increase surface area-to-volume ratio. b) There will be a decrease in internal gas exchange. c) The thickness of the respiratory membrane will decrease the rate at which external gas exchange can occur. d) There would be a decrease in oxygen gas exchange and increase in carbon dioxide gas exchange.
Part complete How would the partial pressures of O2 and CO2 change in an exercising muscle?
a) The partial pressure of O2 would increase, and the partial pressure of CO2 would decrease. b) The partial pressure of O2 would decrease, and the partial pressure of CO2 would increase. c) The partial pressures of O2 and CO2 would remain unchanged.