Red Blood CellsThey look like little cinnamon candies here, but they're actually the most common type of blood cell in the human body - red blood cells (RBCs). These biconcave-shaped cells have the tall task of carrying oxygen to our entire body; in women there are about 4 to 5 million RBCs per micro liter (cubic millimeter) of blood and about 5 to 6 million in men. People who live at higher altitudes have even more RBCs because of the low oxygen levels in their environment.
Red Blood Cells
