NATURE'S WHOOPIE CUSHION

Erythrocytes (erythro - red; -cyte – cell) are red blood cells.  They are responsible for delivering oxygen to the cells of your body.  Oxygen is vital in aerobic respiration.  It keeps us air breathers alive.

Erythrocytes have a protein called hemoglobin that grabs oxygen.  Erythrocytes in humans are shaped like a whoopee cushion.  That allows for increased surface area.  You can stick a lot of hemoglobin (and therefore oxygen) onto a whoopee cushion-shaped erythrocyte. 

As your erythrocytes are zipping around your circulatory system, doing their job, they are getting their energy anaerobically.  Yep, they are not using the oxygen they are carrying!  Isn’t that sweet.

Of all the erythrocyte awesomeness, I was a bit surprised to learn that human erythrocytes do not have a nucleus.  Nope.  Not at all.  Or, at least not at maturity.  When erythrocytes wear out (as all cells do) they get destroyed by cells in the liver and spleen.  Their parts get recycled and used in the production of new erythrocytes.  But wait!  How can we make new erythrocytes if they don’t have a nucleus to give directions?  Well there are a group of special cells in the red bone marrow of … bones.  These cells (stem cells) are a bit magical and can make a wide variety of blood cells including erythrocytes, leucocytes and others.  The stem cells undergo cell division to make daughter cells.  These daughter cells begin to mature into erythrocytes.  A ring of proteins (actin) forms and pinches off a part of the erythrocyte that has the nucleus.  The nucleus is then eaten by macrophages.  Dude.