The 4 Components of Blood

An adult human body has about 4-5 quarts of blood.  The blood carries out oxygen and nutrients to our cells and getting rid of carbon dioxide, ammonia, and other waste products.  Blood plays an important in the immune system and keeping up relatively constant body temperrature.  Blood is a highly specialized tissue composed of many different kinds of components.  Four of the most important ones are red cells, white cells, platelets, and plasma.  All humans produce these blood components.
Red Blood cells
Red cells are also known as  erythrocytes.   They are large microscopic cells without nuclei they are similar to the primitive prokaryotic cells of bacteria.  Red cells normally make up 40-50% of the total blood volume.  They transport oxygen from the lungs to all of the living tissues of the body and carry away carbon dioxide.  The red cells are produced continuously in our bone marrow from stem cells at a rate of about 2-3 million cells per second.  Red cells normally make up 40-50% of the total blood volume.  Hemoglobin is a gas that transport protien molecule that makes up 95% of a red blood cell.  Each red cell has about 270,000,000 iron-rich hemoglobin molecules.  People who are anemic generally have a shortage in red cells.  The red color of blood is mostly due to oxygenated red cells.  Red cells remain viable for only about 4 months before they are removed from the blood and their components recycled in the spleen.
White blood cells
White blood cells are also known as  leukocytes.  They exist in various numbers and  types, but white blood cells make a small part of blood's volume.  White blood cells are found most in the spleen, liver, and lymph glands.  Most white cells are produced from our bone marrow,  from the same kind of stem cells that produce red blood cells.  Other white cells are produced from the thymus glands, which is at the base of the neck.  Most of the time white blood cells are the first responders for our immune system.  They help kill all the bacteria, viruses, and fungi.  Another job of white blood cells is getting rid of dying or dead cells.  Idividual white cells only last about 18-36 hours before they are removed.  Some types of white cells can last up to a year.  There are actually many special sub-types of white cells that participate in different ways in our immune responses.
Platelets are also known as  thrombocytes.  Platelets are cell fragments with nuclei that work with blood clotting chemicals when you get a wound.   Platelets do this by attaching to the walls of blood vessels, when there is a  rupture in the vascular wall.  They also can release coagulating chemicals which cause clots to form in the blood that can plug up narrowed blood vessels.  There are more than a dozen types of blood clottings.  Recently platelets have been known to help fight infection by releasing protein to kill bacteria and other microorganisms.  In addition, platelets are part of the immne system.  Individual platelets are about 1/3 the size of red cells.  They have a lifespan of 9-10 days.  Like the red and white blood cells, platelets are produced in bone marrow from stem cells.