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.

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 link

Can you be more specific

answer: carbon 14 can only be used to determine the age of the organisms that were once living, and igneous rocks are non living.

explanation:

carbon 14 dating is used to determine the age of the sample by estimating the amount of carbon 14 present in the sample and then comparing it with a reference standard.carbon 14 is a isotope of carbon which is radioactive and unstable. carbon 14 is assimilated by all plants and animals throughout their life from carbon dioxide. however, one the organisms die they stop this assimilation and the carbon 14 content starts to decrease.by knowing how much of carbon 14 is left in an organism after his death, one can estimate the age of the organism. the materials whose age can be estimated by carbon 14 method are the organic compounds. however, some inorganic compounds such as aragonite   shell can also be dated.however, if we consider the igneous rocks it is a non living component which never accumulated carbon 14 in it and thus, we cannot use carbon 14 dating method to estimate its age.