Spherocytes

3D Model

The characteristic biconcave disc shape of erythrocytes is held in place by a strong but stretchy network of protein filaments attached to the inside of the plasma membrane. This maximises surface area for gas exchange, allows cells to deform and squeeze through tiny capillaries yet be robust enough to withstand being buffeted round the circulation. Genetic changes in the proteins of this mesh can weaken the tensile strength, internal pressure forces the cells to pop out into a spherical shape to minimise surface tension. The outcome for affected individuals is anaemia. Spherocytes have a reduced surface area so they become less efficient at carrying oxygen. They become less flexible so are unable to pass readily through microcapillaries. They are also less resistant to damage, increasing the chance of cells bursting. Honestly, this wasn’t the most taxing bit of 3D modelling I’ve ever done…