Don't have a nucleus, which means more space for hemoglobin and oxygen
Shaped like a biconcave disc, which gives them a large surface area for absorbing oxygen
White blood cells
Essential part of the immune system, defend against infection
Functions of white blood cells
Phagocytosis (engulf and consume microorganisms)
Produce antibodies that bind to and help destroy pathogens
Produce antitoxins that neutralize toxins produced by pathogens
White blood cells
Have a nucleus, unlike red blood cells
Platelets
Small fragments of cells that float in the blood and help stop bleeding by clotting
Plasma
Pale straw-colored liquid that makes up over half the blood's volume, carries nutrients, waste products, hormones, antibodies, and toxins
Most adults have about 5 liters of blood flowing through their circulatory system at any one time
Artificial blood
Blood substitute consisting of salt water, adds volume to the circulatory system but doesn't contain red blood cells so can only replace about 1/3 of the blood
Blood transfusion
Giving a person real blood donated by blood donors, which contains red blood cells to help survive blood loss
