Hyoid Bone Anatomy
Number of Red Blood Cells in the Blood
Number of Red Blood Cells in the Blood:
As the blood moves throughout the body, it circulates about 20 – 30 trillion red blood cells (RBCs). Even a small drop of blood (1.0 mm3) contains millions of RBCs:
- 4.2 – 5.4 million RBCs/mm3 in males
- 3.6 – 5.0 million RBCs/mm3 in females
- Because they lack a nucleus, RBCs stay viable for only about 120 days and must be replaced at the same rate as they disappear from the blood (= 2.5 million cell/second).
- A high number of RBCs per volume of blood is referred to as polycythemia. When this abnormality occurs, it can increase blood volume, pressure, and viscosity.
High RBC count.
- A low number of RBCs of blood reduces the hemoglobin concentration, which is measured in grams Hb per deciliter (100 milliliters) of whole blood:
- 14 – 18 grams/dL in males
- 12 – 16 grams/dL in females
Low RBC count.
- A low hemoglobin concentration, which is called anemia, decreases oxygen (O2) delivery to the tissues.