Red Blood cells vs White Blood cells?

Question

Which are bigger?

RBC comes from bone marow dosn't it? I think it does

Immunity does it last forever dealing with diseases?

Answer 1

White blood cells are larger.

RBC's and WBC's come from red bone marrow, though their maturation processes are markedly different.

It depends what type of immunity you're referring to. There are 4 types:

Natural active immunity - long term
Ex: When you come into contact with a pathogen and your body develops its own antibodies to fight the invader.

Natural passive immunity - short term
Ex: Mother passes her antibodies through the placenta to the fetus. The fetus retains some of the antibodies after birth, but are usually broken down afterwards.

Artificial active - long term
Ex: A vaccination.

Artificial passive short term
Ex: Antiserums for snake bites, bee stings. This type is for immediate suppression of an invading substance due to their potency.

So in summary, passive immunities are generally short term - their related antibodies disintegrate after a while in the blood stream. Active immunities produce both antibodies and memory cells that will become active when you come into contact with the pathogen again.

Answer 2

White blood cells are larger than RBC.

They both are produced in the bone marrow.

For some diseases, immunity does last pretty much forever. For others, you never develop an immunity and so you can get them again.

Answer 3

I don't know which is bigger, but as for your other questions: All blood cells come from bone marrow. Red blood cells carry oxygen from the lungs to the muscles, white blood cells destroy germs, and platelets close wounds and clot blood.

When white blood cells fight a disease they create antibodies, which "remember" the disease and make it easier to fight next time. This is where immunity comes from. It is usually permanant for a specific disease, but if the disease mutates, the immunity may not affect it.