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
Vasoconstriction does not increase blood *flow*. It increases blood *pressure*. If all things were equal, that would normally increase blood flow. But as you note, making the blood vessels smaller increases the resistance to flow.
If you grab a hose or piece of tubing with liquid flowing through it and squeeze, the upstream pressure rises due to the resistance you’ve added. But the rate of flow goes down.
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