Normally, erythrocytes show very little variation in shape. In order to facilitate their passage through the capillaries, the shape is biconcave. This is due to the combined effect of the cell´s cytoskeleton and oxygen tension.

The course has been created by Lars Hjorth, MD and Stanislaw Garwicz, MD, PhD, both at the Department of Pediatrics, University Hospital in Lund, Sweden, 2000.