Tissue Fluid Flashcards
Which end of the capillary has greater pressure? (Hydrostatic pressure) Explain why
The arterial end because contraction of the left ventricle generates high pressure in the arteries
What is ultrafiltration?
- The process in which small, soluble molecules are forced out of capillaries down a pressure gradient and form tissue fluid.
- Larger molecules, such as proteins, remain in the blood as they are too large to pass through the gaps between the cells in the capillary wall.
What happens to pressure as you move towards the venous end of the capillary? Explain why
Pressure decreases as the volume of tissue fluid within the capillary decreases
What happens to water potential as you move towards the venous end of the capillary? Explain why
Water potential decreases. As water leaves the capillary, the water potential will fall. Additionally, the proteins remaining increase the solute concentration, further decreasing water potential
Why does tissue fluid return to the capillary?
The pressure in the venous end of the capillary is lower than that of the tissue fluid, therefore the fluid returns to the capillary down a pressure gradient. Additionally, as water potential in the capillary is lower than the water potential outside the capillary, water returns via osmosis
The hydrostatic pressure of the blood at the arteriole end of the capillary helps to form tissue fluid. Explain how.
Hydrostatic pressure higher than osmotic “effect”;
Forces / squeezes / pushes out / water / small molecules / ions / examples;
Explain how tissue fluid is formed and how it may be returned to the circulatory system
- (hydrostatic) pressure of blood high at arterial end;
- fluid / water / soluble molecules pass out (reject plasma);
- proteins / large molecules remain;
- this lowers the water potential / water potential becomes more negative;
- water moves back into venous end of capillary (reject tissue fluid) by osmosis / diffusion;
- lymph system collects any excess tissue fluid which returns to blood / circulatory system / link with vena cava / returns tissue fluid to vein;
Oedema is swelling caused by an accumulation of tissue fluid.
Cause: Increased blood pressure
Increases pressure at the arterial end of the capillaries, causing a greater pressure gradient. More tissue fluid is formed as more fluid leaves the capillaries.
Oedema is swelling caused by an accumulation of tissue fluid.
Cause: Damaged capillaries - increased tissue protein concentration
Increased protein concentration decreases the water potential of the tissue fluid. More water leaves the arterial end of the capillary by osmosis.
Oedema is swelling caused by an accumulation of tissue fluid.
Cause: Malnutrition - decreases blood protein concentration
Decreased protein concentration increases the water potential of the plasma in the capillary. Less tissue fluid returns to the capillary by osmosis.
Oedema is swelling caused by an accumulation of tissue fluid.
Cause: Obstruction
(blockage) of lymph vessels
Excess tissue fluid cannot be drained into the lymphatic system and remains in the interstitial space.
The hydrostatic pressure falls from the arteriole end of the capillary to the venule end of
me capillary. Explain why.
Loss of water / loss of fluid / friction (against capillary lining).
High blood pressure leads to an accumulation of tissue fluid. Explain how.
- High blood pressure = high hydrostatic pressure;
- Increases outward pressure from (arterial) end of capillary / reduces inward pressure at (venule) end of capillary;
- (So) more tissue fluid formed / less tissue fluid is reabsorbed.
The water potential of the blood plasma is more negative at the venule end orine capillary than at the arteriole end. Explain why.
- Water has left the capillary;
- Proteins (in blood) too large to leave capillary;
- Increasing / giving higher concentration of blood proteins (and thus wp).
