Plasma, tissue fluid & lymph

• What is tissue fluid?

  Plasma without the plasma proteins. It is forced through capillary walls and bathes cells
• How is tissue fluid formed?

  Arterial end of capillary: low solute potential due to plasma proteins pulls water back into capillary by osmosis. Hydrostatic pressure is greater than osmotic pressure, so water and solutes are forced out of the capillary.

  Venous end of capillary: hydrostatic pressure is lower because its volume has been released by fluid loss. Osmotic pressure is greater (because of a more negative water potential due to more plasma proteins). Water passes back into capillary by osmosis.
• What is lymph?

  Fluid absorbed from between cells into lymph capillaries, rather than back into capillaries
• Where does the lymph come from?

  This is 10% of tissue fluid that does not pass back into capillaries. It drains into the lymph capillaries of the lymphatic system