Tissue Fluid (Mass Transport in Animals)

What is tissue fluid?

• Liquid that surrounds cells in the body

• Cells exchange material with this fluid

What components does tissue fluid contain?

• Water

• Glucose

• Amino acids

• Fatty acids

• Ions

• Oxygen

• Small proteins

What components remain in the capillaries?

• Plasma proteins

• Large proteins

• Platelets

• Red blood cells

Describe the process of tissue fluid formation

1. Blood enters arterial end of capillary

2. Here hydrostatic pressure is high

3. This is due to ventricular contraction and closeness to heart

4. Hydrostatic pressure is greater than the forces of osmosis

5. Therefore fluid from plasma moves out of capillary in direction of the greater force (hydrostatic pressure) via ultra-filtration

Describe the pressure in capillary at arterial end and the result of this

• High hydrostatic pressure

• Tissue fluid forced out of capillary

Describe the pressure in capillary at venous end and the result of this

• Low hydrostatic pressure and low water potential

• Tissue fluid moves in via osmosis