Blood Pressure vs Blood Flow

[Hope888]

Hello fellow Nursies!

I had a question regarding blood pressure vs blood flow. I think I understand the main idea, but I have always been a little confused over this concept:

So I know that vasoconstriction increases blood pressure, as the diameter of the vessel is smaller and so the blood will be hitting against the artery. However, what I'm confused about is this. So if someone was hypotensive, a compensatory response would be to vasoconstrict the arteries, as that will bring the blood pressure back up. But, doesn't vasoconstriction DECREASE blood flow, as the systemic vascular resistance is increased now, so I don't understand why vasoconstriction would be helpful if it decreases blood flow.

Here are 2 reasons why I think vasoconstriction is important in this situation, and I would love it if someone was able to clarify if my thinking is correct:

1. I think that it depends on WHICH vessels are vasoconstricted. So, it would make sense to me that organs that are not critical (such as the skin and intestines) would be constricted so that blood flow could be re-routed to critical organs, such as the brain and heart.

2. I'm guessing that vasoconstriction would also be helpful in the case of a low blood volume because if the vessel diameter decreases, that would build pressure, thus forcing blood to flow, and at a faster rate - I'm most uncertain about this, though, so I would really appreciate it if someone could clear up this confusion for me!

I guess I'm just confused about this whole vasoconstriction/vasodilation thing in relation to blood pressure and blood flow. At one end, I feel like vasoconstriction would increase Pressure, thus helping our blood to flow - but then if our vessels constrict, that would also decrease blood flow? It just seems very contradictory to me.

Thank you guys for your help in advance!