HPV is a homeostatic mechanism

Question 1

Hypoxic pulmonary vasoconstriction (HPV)

Answer 1

is a homeostatic mechanism intrinsic to the pulmonary vasculature

independent of hormonal or neural mechanisms

Question 2

HPV describes the contraction of smooth muscle in the walls of small pulmonary arteries in order to…

Answer 2

divert blood flow away from poorly ventilated regions of the lungs

Question 3

Benefits of HPV

Answer 3

ultimately improves ventilation/perfusion matching and aims to restore systemic oxygen delivery to the tissues

Question 4

However, during sustained high altitude exposure

Answer 4

the whole lung will present as hypoxic leading to diffuse HPV of the pulmonary vasculature

Question 5

Constriction of the pulmonary vasculature ultimately leads to

Answer 5

increased pulmonary vascular resistance as the reduction in vessel diameter opposes the motion of blood flow

Question 6

In order to overcome this resistance, therefore

Answer 6

the PAP is increased alongside an increase in workload by the right heart

Question 7

FM, vascular remodelling of pulmonary vessels in response to

Answer 7

chronic hypoxia exposure contributes to the sustained increase in arterial pressure

Question 8

Medial thickening and presence of both an internal and external elastic lamina in

Answer 8

intra-acinar blood vessels taken from rats following 2 weeks exposure to hypoxia (FIO2=10%) demonstrated the effects of chronic hypoxia on vascular remodelling (Howell et al. 2003)