Mathematix (Offline)

Almost everything you say is consistent with what I think; I know that will sound weird, as it would if I heard it! So odd!

Explain how tissue fluid is formed and how it may be returned to the circulatory system? (6 marks)

There is a high hydrostatic pressure at the arteriole end of the capillary, due to heart contraction.

This pressure causes filtration of plasma containing (glucose, hormones, amino acids, water) to pass out of the permeable capillary wall. The filtered plasma forms tissue fluid which surrounds body cells.

Large plasma proteins and red blood cells are too large to fit through the gaps so remain in the capillary.

They dissolve and lower the water potential of the fluid inside the capillary. So water moves back into the capillaries by osmosis at the venous end of the capillary where there is a low hydrostatic pressure.

Because the process is slow, there will be excess tissue fluid. This enters the lymphatic vessel and is now called Lymph. The lymphatic system returns the lymph back to the blood.

Hope this helps!