Our blood is fluid for a reason. Its fluidity allows for cells swimming in the circulation to move quickly throughout the body. The main cells of our blood are called red blood cells and they are the ones that give the blood its red color.
What are red blood cells
First off, red blood cells is a common misnomer and the “c” in RBCs is referring to corpuscles not cells, since red blood corpuscles don’t have a nucleus and they are mostly a biconcave red disc that is formed mainly of hemoglobin. Hemoglobin in RBCs is a protein that contains iron ions. Its function is to carry oxygen from the lungs to various body organs. Oxygen is essential for the production of energy from food and without energy, body organs can’t function especially the brain and death results. RBCs are produced in the bone marrow through the division and differentiation of their mother cells called hematopoietic stem cells.
The normal level of RBCs in the circulation is 4.7-6.1 million cells per cubic microliter for males and 4.2-5.4 million cells per cubic milliliter in females. Each liter has a million microliters and our body has an average of 5 liters of blood. This difference in count between males and females can be attributed to the effect of testosterone in males which increases the production of RBCs from the bone marrow as well as the monthly loss of red cells by women in the form of menses. Normal hemoglobin level is 13.5-17.5 grams per deciliter for males and 12-15.5 grams per deciliter in females. A fall in the level of hemoglobin is called anemia.