- know that erythrocytes are part of the formed elements
- know what a erythrocyte is
- know what the functions of erythrocytes are
- know how the structure of a erythrocyte influences its function
- understand the pros and cons of erythrocyte structure
This packet covers the structure and function of the most abundant formed element in blood, erythrocytes.
Erythrocytes (red blood cells, RBC's) are part of the formed elements(cellular composition) of blood. Erythrocytes, in fact, are the most abundand compoenent of the formed elements. There are about, on average, 4-5 million erythrocytes per microliter of blood, that's a lot! Erythrocytes have one major function to them, transport gases around the body.
The structure of erythrocytes allows them to be much more effective at performing their job. For starters, erythrocytes are anucleated (no nucleus). Without the nucleus present this provides about 33% more surface area for hemoglobin. Remember that hemoglobin is the part of a erythrocyte that these gases stick to and are circulated on. Essentially the more the hemoglobin, the more oxygen the erythrocyte is capable of carrying.
Erythrocytes don't really have any of the major organelles, the one thing that they do have in common with other cells is the cytoskeleton. The cytoskeleton of erythrocytes is very flexible and allows them to bend and contort to the size of the microcirculation (small vessels).
The lack of a nucleus though is detrimental to the lifespan of the erythrocytes, however. As erythrocytes bend and squeeze through the smallest vessels of the body their cytoskeletal proteins fall apart. Without a nucleus and other organelles they are unable to replace the damaged cytoskeletal proteins. Eventually, they will be squeezed through the small capillaries of the spleen where they will burst. Once the old erythrocytes burst, phagocytes in the spleen consume what's left of the dead cells.
Source: Mind of Aaron
Source: Self made
Source: Self made