Question

Explain the significance of red blood cell deformation on the viscosity of whole blood. Be sure to address how/why red blood cell deformation leads to a change is whole blood viscosity

Answer 1

FACTORS AFFECTING THE VISCOSITY OF BLOOD:

1. Haematocrit

2. Plasma viscosity

3. Cell aggregation

4. Cell deformability.

Now, lets look at RBC deformability and how it affects the blood viscosity.

Normal shape of the RBCs is- Biconcave allowing in easy flow of RBCs through thin and tortuous capillaries and vessels.

RBCs deformability means the ability of these cells to change their shape in response to applied force which may be external or internal. Now, this deformation can be in the form of either change in cell curvature, uniaxial deformation or cellular expansion. This ability to deform may depend on several factors such as ; Anatomy of the RBC membrane, physical properties of the intracellular fluid, geometry of RBCs.

Any decrease in the deformability of RBCs while it passes through vessels or capillaries will lead to difficult and slow passage of these cells causing aggregation of these cells leading to an increase in the blood viscosity and thus overall slowing down of the blood flow.