Fluid that surounds cells in tissues.
Made From substances that leave blood (Oxygen, Glucose ect.)
Cells take in oxygen from tissue fluid and release metabolic waste into it.
Tissue Fluid Formation
Blood is pumped from the heart and passes through arteries, then Arteroles, then Capillaries.
These blood vessels become increasingly narrower. This creates a pressure called electrostatic pressure at the arteriole end of the capillaries.
This pressure forces tissue fluid out of the blood plasma, but is opposed by the hydrostatic pressure outside the capillaries and low water potential of the blood, causing water to be drawn back into the capillaries.
This results in a lower pressure that can only force small molecules out of the blood of capillaries, leaving behind large molecules such as cells or protiens.
This process is called Ultrafiltation.
Return of Tissue Fluid to the Circulatory System.
Once Tissue fluid has exchanged metabolic materials with cells, it is reabsorbed back into the Capillaries. Itsnow has a higher hydrostatic pressure than inside the capillaries, and a higher water potential, so moves back into the capillaries.
A small amount is unable to pass back into the capillaries. This is taken in by the lymphatic system ad becomes lympth. Lympth is moved by Hydrostatic attraction and movement of body muscles.