Question

5. Describe the structural organization of the membrane skeleton that is a major determinant of red cell shape and deformability.

Answer 1

Deformability refers to the capacity of the erythrocyte to undergo distortions and deformations and then resuming its normal shape without fragmentation or loss of integrity

The cellular deformability of erythrocytes is determined by three factors: (1) biconcave disc shape; (2) cytoplasmic viscosity (determined by the properties and the concentration of hemoglobin in the cells); and (3) intrinsic visco elastic properties of the red cell membrane (or membrane deformability)

The biconcave shape allows red cells to stretch as they undergo deformation and distortion in response to the mechanical stress of the circulation

Human erythrocyte membrane is composed of three major structural elements:

1.A lipid bilayer primarily composed of phospholipids and cholesterol

2.Integral proteins embedded in the lipid bilayer that span the membrane

3.A membrane skeleton on the internal side of the red cell membrane

The unique deformability, of RBC during repeated passages through narrow microcirculatory channels is provided by the red cell membrane and its skeleton. The lipid bilater maintains a slippery exterior so that erythrocytes do not adhere to endothelial cells or aggregate and occlude the microcirculation.

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