Principles of Physiology Membrane Permeability

The process of haemolysis involves bursting of the semipermeable cell membrane of the red cells. This led to the reduction in their numbers in the solution. In C, D, and E, the extracellular solutions are hypertonic to the intracellular fluids. This means that the concentrations of sodium chloride in the solutions are higher compared to that in the cytoplasm of the red blood cells (Practical Manual, p. 54). This makes the cells lose water through osmosis via the semipermeable membranes. The cells, therefore, maintain their original number depending on the concentration of the solutions.
The cells in the variant B are swollen and are biconvex in shape while those in E are created and are biconcave in shape. Solution B is a hypotonic solution, therefore, water molecules move from the solution into the cell cytoplasm through the process of osmosis via the semipermeable cell membrane (Blum, 2006, p. 45).
Osmolarity versus degree of haemolysis. Osmolarity was obtained through the use of arbitrary scale in the assessment of the size of the pellets and noting the supernatant colour. + Sign represents the number of pellets that resulted from the haemolysis of the red blood cells. The two value types have close relations and are dependent on each other, thus, they can be plotted on a graph as shown above. The osmolarity is directly proportional to the degree of haemolysis.
The degree of haemolysis represented by the number of red blood cells pellets is directly proportional to the osmotic pressure exerted by the intracellular fluid and the plasma on the cell membrane. This is because osmotic pressure reduces and hinders osmosis from taking place. When osmosis fails to take place across the membranes of the red blood cells, there is no continuous inflow of water molecules through the cell membrane. therefore, the cells do not haemolyse, thus the least number of pellets of red blood cells when the osmolarity is the lowest.