A human red blood cell is a dimpled ballerina, ceaselessly spinning, tumbling, bending, and squeezing through openings narrower than its width to dispense life-giving oxygen to every corner of the body. In a paper published in the October issue of Annals of Biomedical Engineering, which was made available online on Oct. 21, a team of UCSD researchers describe a mathematical model that explains how a mesh-like protein skeleton gives a healthy human red blood cell both its rubbery ability to stretch without breaking, and a potential mechanism to facilitate diffusion of oxygen across its membrane.