Codocytes, also known as target cells, are red blood cells that have the appearance of a shooting target with a bullseye. ... These cells are characterized by a disproportional increase in the ratio of surface membrane area to volume.
While all cells are exposed to hormones circulating in the bloodstream, not all cells react. Only a hormone's "target" cells, which have receptors for that hormone, will respond to its signal. When the hormone binds to its receptor, it causes a biological response within the cell.
