Tissue fluid

Question 1

What is tissue fluid?

Answer 1

fluid that surrounds cells in the tissues made up of small molecules that leave the blood plasma e.g. water, glucose
(bathes the tissues)

Question 2

How is tissue fluid formed?

Answer 2

• capillaries have small fenestrations in the walls so that liquid and small molecules can be forced out
• as blood enters the capillaries from arterioles, the smaller diameter results in a high hydrostatic pressure so small molecules are forced out (ultrafiltration)
• hydrostatic pressure is higher than the effect of the water potential
• Proteins remain in the blood

Question 3

How is tissue fluid reabsorbed?

Answer 3

• as the fluid leaves, the hydrostatic pressure reduces in the capillaries
• large molecules remain in the capillaries creates a lowered water potential so water re enters via osmosis

Question 4

What is the lymph’s role in tissue fluid?

Answer 4

• any excess tissue fluid is drained into the lymphatic system which transports the excess fluid from the tissues and passes it back into the circulatory system/bloodstream near the heart
• equilibrium will be reached in osmosis but some fluid will still surround the cells