by
Rabee Niami , ACT Test Center Supervisor , International Independent Schools (Airport road branch)
Human blood cells are very similar to those of other animals, though there are a few interesting differences. Both human and animal blood cells can have A or B antigens, or both or neither, resulting in blood typing of A, B, O, or AB. They can also have Rhesus (Rh) antigens.
Animals with an open circulatory system have hemolymph rather than blood, and hemolymph use hemocyanin instead of hemoglobin to transport Oxygen.
Red blood cells in humans differ from those of many animals in that they do not have nuclei. Most animals, besides mammals, have nuclei in their mature red blood cells. Mature mammalian red blood cells lose their nucleus and organelles in order to carry more hemoglobin, and they do not need to use any oxygen themselves. Erythrocytes are round in all mammals except camels, who have oval erythrocytes.