If you’ve lost blood, either by a severe cut or donating to a blood bank, your body can generate new blood to replace it. How does your body know when it needs more, and how does it know when to stop so you don’t end up with an excess amount?

Question

If you’ve lost blood, either by a severe cut or donating to a blood bank, your body can generate new blood to replace it. How does your body know when it needs more, and how does it know when to stop so you don’t end up with an excess amount?

In: Biology

Answer 1

I’ll add that there’s a part of your brain that can detect when the volume of blood is too low. When this happens, the pituitary secretes ADH that causes the kidneys to conserve more water instead of excreting it in urine. This helps maintain the volume of blood and blood pressure in addition to the actual amount of red blood cells which has been explained by others here (erythropoietin).