Pulmonary arterioles and system arterioles when PO2 is low. A. dilate, dilate B. dilate, constrict C. constrict, dilate D. constrict, constrict Definition C. constrict, dilate

Pulmonary arterioles constrict and system arterioles dilate when PO₂ is low.

Explanation:

Oxygen partial pressure (PO₂) is a blood perfusion parameter that indicates the O₂ concentration in the blood, related to the O₂ available in the lung alveolus or in the body tissues, at a given time.

Since gas exchange depends on the amount of O₂ and CO₂ -which determines both PO₂  and PCO₂- blood circulation and lung ventilation, a decrease or increase in PO₂  will result in significant vascular changes to ensure O₂ flow in the body.

These adaptations make it possible to increase the bioavailability of O₂

and thus increase the PO₂.

Learn more:

PO₂ at the arterial ends of the pulmonary capillaries link

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