I keep reading, as a science student, that when blood flow or pressure goes down, arterioles constrict in order to raise blood pressure. But vasoconstriction actually increases resistance, thereby depriving the tissue further of blood flow.
So what is it that I’m not understanding?
In: Biology
Constricting does not improve flow, it does improve the pressure gradient though. The alternative is to stay dilated and further deprive the tissues of needed oxygen. Constricting the vessels allows the hydrostatic pressure to stay close to the same as before the drop in BP occurred. Further constriction also diverts blood away from less-important tissues like fingers and toes and allows it to be sent to the core organs and brain easier. Also, check out laminar flow and turbulent flow in relation to blood flow.
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