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
It has to do with the areas that it’s happening. Vasoconstriction in one area – say, a lacerated hand – would increase blood pressure and blood flow in the rest of the body. Just like anything else in the body, vasodilation and Vasoconstriction are not uniform throughout the body.
From what little I know, Vasoconstriction would usually occur in an injured area and also tends to occur in extremities in the cold. While this would reduce the blood flow in that area, it would increase blood pressure and blood flow in other areas of the body so that it doesn’t suffer from a sudden pressure drop that the heart cannot keep up with.
So, in a way, it does both. It decreases blood flow in the area that is constricting; however, it raises pressure and flow elsewhere in the body.
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