Meet the Erythrocyte
◉ Red blood cells take up 45% of your blood volume and circulate about once in 20 seconds, carrying vital oxygen to every nook and cranny of your body. Did you know that ~2.4 million of these are produced each second? That’s because they have a short life span of only about 120 days.
◉ Please squeeze me: The image shows a red blood cell squeezing through a tiny capillary: to accomplish this maneuver, the red cell sacrifices its nucleus and mitochondria to become a flexible, biconcave disk. In the inset, is a deformed red cell from a patient with sickle cell disease shown next to a normal cell. A single mutation in hemoglobin, the oxygen carrier of red blood cells, causes the proteins to clump giving the cells their characteristic sickle shape. The deformed cells block capillaries and burst more easily, surviving only 10-20 days.
◉ Heterozygote advantage: Given the severe health complications from sickle cell disease, why does the mutation persist in some populations? You might expect that negative selection against affected individuals would have eliminated the mutation. It turns out that carriers of the mutation (who have one normal copy and one mutated version of the gene), have mild sickling of their red blood cells which also makes them more resistant to infection by the malarial parasite. In fact, sickle cell disease is more common in areas where malaria is endemic.
Another installment of an #excyting series on cells. This one is for Chad Haney who celebrates his birthday today and is my fellow conspirator in science outreach on Google Plus. Chad worked on generating a blood substitute as a graduate student. #HappyBirthdayChad #HappyBirthdayMrMRI #ScienceEveryday #ScienceSunday