Ch 49: Hypoxia and Cyanosis

Question 1

What does HIF-1 stand for?

Answer 1

hypoxia-inducible factor-1

Question 2

During hypoxia, systemic arterioles ______, at least in part, by opening of K+-ATP channels in vascular smooth-muscle cells due to the hypoxia-induced reduction in ___ _____________.

Answer 2

dilate

ATP concentration

Question 3

In contrast, hypoxia induces pulmonary arterial constriction, shunts blood away from poorly ventilated portions toward ______ __________ portions of the lung; however, it also increases pulmonary vascular resistance and right ____________ _________.

Answer 3

better ventilated

ventricular afterload

Question 4

High-altitude illness is characterized by headache secondary to ________ ____________, gastrointestinal symptoms, dizziness, insomnia, fatigue, or somnolence. Pulmonary arterial constriction and sometimes venous constriction causes capillary leakage and ____-________ _________ _____ which intensifies hypoxia, further promoting vasoconstriction.

Answer 4

cerebral vasodilation

high-altitude pulmonary edema (HAPE)

Question 5

The most common cause of respiratory hypoxia is ventilation-perfusion mismatch resulting from…

Answer 5

…perfusion of poorly ventilated alveoli.

Question 6

As in anemic hypoxia, the Pao2 in circulatory hypoxia is usually normal, but venous and tissue Po2 values are reduced as a consequence of…

This condition of generalized circulatory hypoxia occurs in…

Answer 6

….reduced tissue perfusion and greater tissue O2 extraction.

…heart failure and in most forms of shock.

Question 7

How can localized hypoxia result from venous obstruction?

Answer 7

expansion of interstitial fluid causes arteriolar compression and, thereby, reduction of arterial flow

Question 8

How can edema cause localized hypoxia?

Answer 8

Edema increases the distance through which O2 must diffuse before it reaches cells.