Which of the following statements about the response of arteriolar smooth muscle to changing oxygen partial pressures is TRUE?

A. Both systemic and pulmonary arterioles respond to a decrease in PO₂ by constricting.

B. Both systemic and pulmonary arterioles respond to a decrease in PO₂ by dilating.

C. Systemic arterioles respond to a decrease in PO₂ by dilating, but pulmonary arterioles constrict in response to decreased PO₂.

D. Systemic arterioles respond to a decrease in PO₂ by constricting, but pulmonary arterioles dilate in response to decreased PO₂.

E. Changes in PO₂ do not affect arteriolar smooth muscle in the pulmonary system.

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Biology

5 July, 20:44

Which of the following statements about the response of arteriolar smooth muscle to changing oxygen partial pressures is TRUE?

A. Both systemic and pulmonary arterioles respond to a decrease in PO₂ by constricting.

B. Both systemic and pulmonary arterioles respond to a decrease in PO₂ by dilating.

C. Systemic arterioles respond to a decrease in PO₂ by dilating, but pulmonary arterioles constrict in response to decreased PO₂.

D. Systemic arterioles respond to a decrease in PO₂ by constricting, but pulmonary arterioles dilate in response to decreased PO₂.

E. Changes in PO₂ do not affect arteriolar smooth muscle in the pulmonary system.

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Answers (1)

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Kieran Larson · Answer 1

C. Systemic arterioles respond to a decrease in PO₂ by dilating, but pulmonary arterioles constrict in response to decreased PO₂.

Explanation:

In the arterioles, vasoconstriction is a response to high oxygen while vasodilation is a response to carbon dioxide and low pH. However, in the pulmonary arterioles, vasoconstriction occurs as a response to low oxygen and this mechanism is called hypoxic pulmonary vasoconstriction (HPV).