They are tiny (7.5u in diameter, 2u thick) biconcave discs.
A few facts about RBCs
They survive for about 120 days.
The average normal RBC count is
- for men 5.4 million/uL
- for women 4.8 million/uL
Hemoglobin is the most important component of red blood cells. It is composed of a protein called heme, which binds oxygen. In the lungs, oxygen is exchanged for carbon dioxide. Abnormalities of an individual's hemoglobin value can indicate defects in red blood cell balance. Both low and high values can indicate disease states.
A feedback exists – if the RBC count rises, further increases are inhibited.
Low levels of oxygen in the atmosphere stimulate the formation of RBCs. This is an important part of the body’s adjustment to high altitudes. People living in the mountains actually do have higher RBC counts than usual.
RBC formation is regulated by a substance secreted by the kidneys.
none none Strong Pulse: de-oxygenated (except pulmonary vein) exchanging nutrients and gases with cells Oxygenated (except pulmonary artery) Blood is: thin very thin and leaky - one cell thick thick and muscular with elastic fibres Walls are: very low low high Pressure: towards the heart from arteries to veins away from the heart Carry blood: Veins Capillaries Arteries