Why does hypoxia induced vasoconstriction happen in lungs?
The mechanism by which it happens is understood. Is there a reason behind it?
Hypoxia sensitive K+ channels closes(they dont work without oxygen): depolarization current spreads across smooth muscles of vessel-> Ca+2 influx occur and vasoconstriction happen.
Everywhere occur vasodilation in response to hypoxia except Lungs where happen Vasoconstriction to prevent V/Q mismatch so that blood are shifted to those areas which are effectively ventilated from those which are collapsed
Due to vsoconstriction perfusion will decrease, which goes against the hypoxic condition… how is vsoconstriction in lung helping
no rather it is helpful. Suppose there are 100 alveoli In a Patient with ILD out of which 40 has collapsed. Would you want blood to go to those 40 collapsed alveoli?? Obviously NOT because that blood will not get oxygenated and will lead to formation of a shunt. Thats why vessels around those collapsed alveoli undergoes vasoconstriction so that all that blood can be shifted to those 60 open alveoli which is functioning now