Question: Where does your blood come from?

Angus Cook answered on 16 Jun 2016:

This is not really my area of expertise, so someone else can probably answer it better, but it’s probably important to think about what’s actuall IN blood:

1) Blood plasma (Mainly water, with sugars, fats, proteins) – we get this from the food and drink that we eat and… well, drink. When people give blood, or lose blood in an accident the can be told to drink plenty of water, as this will help the body refill itself with the blood it needs.
2) Red blood cells – these are made in our bone marrow. This is special tissue that’s inside our bones. A red blood cells is useful for about 100 days before it breaks down, so the bone marrow is constantly producing new ones to renew our blood.
3) White blood cells – These are the cells that can help fight infections. Some of these are made in the bone marrow again, but some can be made in a special organ in the back of your neck.
4) Platelets – These are little cells or cell fragments which help your blood to clot and form a scab when you’ve had an accident or a graze. Again, these are made from the bone marrow.

So, short answer: Mainly from your bone marrow, as well as from the things we eat and drink.