Hydrostatic and Osmotic Pressure 💧

What is hydrostatic pressure?

The pushing force of fluid inside the capillaries against the vessel walls

What effect does hydrostatic pressure have on water and solutes?

It pushes water and solutes out of the bloodstream

When does filtration occur in capillaries?

When the hydrostatic pressure inside the capillary is higher than the external pressure, it forces fluid and small solutes out

What is osmotic (colloid osmotic) pressure?

The pulling force of solutes (mainly plasma proteins) that draws water into the capillaries

What effect does osmotic pressure have on water?

It pulls water into the bloodstream

How does osmotic pressure interact with hydrostatic pressure?

Osmotic pressure opposes hydrostatic pressure by pulling water in, while hydrostatic pressure pushes water out, acting in opposing directions

When does reabsorption occur in capillaries?

When the osmotic force is greater than the hydrostatic force, water is pulled back into the capillaries.

What is the difference between hydrostatic and osmotic pressure in simple terms?

Hydrostatic pressure = pushing force of fluid
Osmotic pressure = pulling force of solutes

What does “filtration” mean in physiology?

Passing through a filter, not being trapped by it. The filtrate is what moves through (like coffee passing through a filter), while larger particles are retained.