…but it was all in vein (get it? all in vein?)
There are 2.5 trillion blood cells in your body.
Blood cells are made in the bone marrow. The bone marrow produces 95 percent of the body’s blood cells.
Blood cells that form in the marrow start out as a “stem cell”. The stem cells mature into red blood cells, white blood cells, and platelets.
Red blood cells carry oxygen to the tissues, and carry carbon dioxide away from the tissues and back to the lungs.
White blood cells fight infection. There are 30-40 billion white blood cells in the body that fight infections, such as bacteria. Some white blood cells release histamine when pollen or allergens enter the body, and that is what causes an allergic reaction. Some white blood cells can even “remember” prior infections and attack them!
Platelets form a clot if there is a cut. The body makes 100 billion platelets a day.
White blood cell eating a bacteria:
Healthfacts.blog 