Question

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

Answer 1

Answer:

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.

• When the PO₂ in the alveolus decreases, the pulmonary arterioles contract, to redirect the blood to other better ventilated alveoli.
• In the tissues, a decrease in tissue PO₂ causes arterioles dilatation, which should promote the arrival of O₂ in that tissue.

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 brainly.com/question/9501095