how does blood pressure work?


I used to think blood pressure the same way as a can of fizzy drink, that if there is too much you must get rid of some blood by bleeding out. But somehow I don’t think that is the case as it sounds a bit extreme, and I’ve also heard of medication that lowers it(?).

In: Biology

That is true, the body does ad and remove water from the blood to lower its pressure. It does this by using salt but also your body can open and close the veins to also regulate blood pressure.

So let’s say you have a pump (the heart) and hoses (your circulatory system) and 5 liters of water (your blood).
If you change any part of this, it will change the pressure.
Ex : if the pump is not effective, the water doesn’t flow properly and doesn’t get to the places it needs to go. So you have low pressure.
If you have very small hoses then the more water you push through them the more the pressure goes up.
Or, wide hoses, less pressure.
If you have no water, the pressure is lower. If you have a lot of water, the pressure is higher.

There’s all kinds of things that affect blood pressure. And yes, if you eat a lot of salt and fat it affects your pressure. If you have kidney failure it affects your pressure.
You also have little receptors all over your body that measure the pressure. And they provide feedback to make the whole system work properly ( let go of water, raise your heart rate, relax your veins etc)

No your blood is not fizzy pop. (As any vampire will be quick to confirm)

There are a number of factors that affect blood pressure, and blood volume is only one. Another is the strength of the heart as it pumps. A weak heart is not able to pump as strongly as a healthy heart, so there will be a drop in the blood pressure. Another is the arteries a congested artery will allow less blood to flow, driving the blood pressure ups
Drugs and medication can also affect the blood pressure both raising and decreasing it depending on the type of medication. Even things like exercise, stress or shock can release hormones into the blood that will affect the blood pressure.