<Li> 4.7 to 6.1 million ( male ) , 4.2 to 5.4 million ( female ) erythrocytes : Red blood cells contain the blood 's hemoglobin and distribute oxygen . Mature red blood cells lack a nucleus and organelles in mammals . The red blood cells ( together with endothelial vessel cells and other cells ) are also marked by glycoproteins that define the different blood types . The proportion of blood occupied by red blood cells is referred to as the hematocrit , and is normally about 45 % . The combined surface area of all red blood cells of the human body would be roughly 2,000 times as great as the body 's exterior surface . </Li>
<Li> 4.7 to 6.1 million ( male ) , 4.2 to 5.4 million ( female ) erythrocytes : Red blood cells contain the blood 's hemoglobin and distribute oxygen . Mature red blood cells lack a nucleus and organelles in mammals . The red blood cells ( together with endothelial vessel cells and other cells ) are also marked by glycoproteins that define the different blood types . The proportion of blood occupied by red blood cells is referred to as the hematocrit , and is normally about 45 % . The combined surface area of all red blood cells of the human body would be roughly 2,000 times as great as the body 's exterior surface . </Li>
the percentage of red blood cells compared to blood volume is known as
the percentage of red blood cells compared to blood volume is known as
hematocrit
hematocrit