3.2.4 Tissue Fluid

Question 1

What is tissue fluid

Answer 1

• Fewer proteins than blood (too large to fit through gaps in capillary walls)
• Bathe almost all cells in body outside of circulatory system
• Exchange of substances occurs here

Question 2

How does tissue fluid form?

Answer 2

• At arterial end of capillary, hydrostatic pressure forces liquid out of capillary
• Proteins remain in blood because they are too big to pass through capillary wall
• Increased protein content remaining in capillaries creates a water potential gradient
• Arterial end, hydrostatic is greater than osmotic pressure so net movement of fluid is out of capillaries
• At venous end, hydrostatic pressure within capillary is lower than osmotic pressure
• Water flows back into capillaries by osmosis
• 90% of fluid lost at arterial end is reabsorbed at venous end 10% goes to lymph vessels

Question 3

What is lymph

Answer 3

• Large molecules that cant pass through capillaries enter lymph system
• Lymph moves along large vessels whose flow is monitored by body movements. Backflow is prevented by valves
• Eventually reenters blood stream

Question 4

Difference between Composition of plasma and tissue fluid

Answer 4

1. Higher conc of glucose in plasma
2. Higher conc of glycerol and fatty acids in plasma
3. Higher conc of amino acids in plasma
4. Higher conc of plasma proteins in plasma
5. Higher conc of O2 in plasma
6. Lower conc of CO2 in plasma
7. Tissue fluid contains a higher conc of substances secreted by cells ,eg. insulin