GENERAL HISTOLOGY

Detailed explanation-1: -The small purple cells (pictured at left) are platelets. Notice that they are smaller than the red blood cells around them. Medical laboratory scientists may be asked by doctors to count the number of platelets a patient has in their blood. The same instrument that counts the red blood cells can also count platelets.

Detailed explanation-2: -Platelets are not true blood cells as they lack a nucleus.

Detailed explanation-3: -The iron-containing heme group found in hemoglobin in human blood gives blood its red color. However, other species, like brachiopods, have hemerythrin, which when oxygenated causes their blood to appear purple. As a result, human blood is red and does not come in a purple variety.

Detailed explanation-4: -Contrary to their name, white blood cells are colorless but can appear as a very light purple to pink color when examined under a microscope and colored with dye. These extremely tiny cells have a round shape with a distinct center membrane (nucleus).