Tissue fluid and lymph fluid formation

Question 1

What is tissue fluid?

Answer 1

The solution surrounding cells of multicellular animals

Question 2

What is oncotic pressure?

Answer 2

The tendency for water molecules to leave by osmosis, created by plasma proteins(always -3.3kpa)

Question 3

What is hydrostatic potential?

Answer 3

The pressure created by the contractions at the heart
+4.6kpa at arterial end.
+2.3 at venous end.

Question 4

How is tissue fluid formed?

Answer 4

BP is higher at arterial end of capillary, so hydrostatic pressure is greater than oncotic so water leaves capillary via osmosis. Filtration pressure of +1.3kpa. BUT plasma proteins are too large to leave, so they remain in the capillary.

The hydrostatic pressure at the venous end is lower than at arterial so the filtration pressure is -1kpa, so water enters via osmosis. This is due to the plasma proteins that remained in the capillary. (90% of TF returns)

Question 5

How is lymph fluid formed?

Answer 5

The remaining 10% of TF drains into a series of blind ended lymph capillaries, which connect into larger lymph vessels forming the lymphatic system

Question 6

Describe the movement of lymph fluid

Answer 6

Contractions by nearby skeletal muscles which squeeze the lymph capillaries.
They vessels also contain valves to ensure the fluid moves forward
It then returns to blood stream via blood vessels under collar bone