Not Medical Advice: According to Redcrossblood.org, in the blood stream, there are about 600 red blood cells for every white blood cell. Therefore, there's 60,000 red blood cells.
The average human adult has more than 5 liters (6 quarts) of blood in his or her body. Blood carries oxygen and nutrients to living cells and takes away their waste products. It also delivers immune cells to fight infections and contains platelets that can form a plug in a damaged blood vessel to prevent blood loss.
If a test tube of blood is left to stand for half an hour, the blood separates into three layers as the denser components sink to the bottom of the tube and fluid remains at the top.
The straw-colored fluid that forms the top layer is called plasma and forms about 60% of blood. The middle white layer is composed of white blood cells (WBCs) and platelets, and the bottom red layer is the red blood cells (RBCs). These bottom two layers of cells form about 40% of the blood.
Plasma is mainly water, but it also contains many important substances such as proteins (albumin, clotting factors, antibodies, enzymes, and hormones), sugars (glucose), and fat particles.
All of the cells found in the blood come from bone marrow. They begin their life as stem cells, and they mąture into three main types of cells:
RBCs
WBCs
Platelets
In turn, there are three types of WBC:
Lymphocytes
Monocytes
Granulocytes
And three main types of granulocytes:
Neutrophils
Eosinophils
Basophils
Eight days. That's how long it takes for skin cells to reprogram into red blood cells. Researchers at Lund University in Sweden, together with colleagues at Center of Regenerative Medicine in Barcelona, have successfully identified the four genetic keys that unlock the genetic code of skin cells and reprogram them to start producing red blood cells instead. Read more at Sciencedaily.com.