|
Two to three trillion erythrocytes or red blood cells (RBCs) circulate in the blood stream of an average adult, and each is uniquely designed to transport and exchange oxygen (O2) and carbon dioxide (CO2).
Mature RBCs are small, disc-shaped cells that measure 7-8 micrometers (um) in diameter. As they mature, RBCs extrude their nucleus, which causes the center of the cells to collapse. The resulting biconcave shape gives RBCs more surface area than spherical cells of the same size. This modification allows O2 and CO2 to move more quickly through the plasma membrane. The raised edges that are created when the cell collapses measure about 2-3 micrometers (um) in thickness. |
