Tissue Fluid

Question 1

What is tissue fluid?

Answer 1

Fluid containing water, glucose, amino acids, fatty acids, ions and oxygen. It surrounds tissues

Question 2

How is tissue fluid formed?

Answer 2

• Blood enters capillaries from arteriole end, small diameter so high hydrostatic pressure which forces out glucose, water etc. (ultrafiltration)
• Red blood cells, platelets and proteins remain in capillary

Question 3

How is tissue fluid reabsorbed?

Answer 3

• Large molecules such as rbc and proteins remain in capillary
• Lowers the water potential
• Towards venule end, hydrostatic pressure and water potential low
• Water re-enters via osmosis

Question 4

What role does the lymphatic system play in this?

Answer 4

• Not all liquid is reabsorbed by osmosis as an equilibrium is reached
• Remaining tissue fluid absorbed into lymph vessels, which surround blood vessels
• The lymphatic system then drains this fluid back into the blood next to the heart