Blood, Tissue Fluid and Lymph

Blood

Contains dissolved substances such as: oxygen, carbon dioxide, amino acids, hormones, salts, glucose, fatty acids and plasma proteins.

Tissue fluid

Similar to blood - but does not contain most of the cells as well as plasma proteins.

Role: To transport oxygen and nutrients from blood to the cells. 

How is tissue fluid formed?

1- Artery reaches tissues, branches into arterioles - then into network of capillaries. 

2- Capillaries will eventually link up with venules - carry blood back to vein

3- Blood entering organ/tissue contained in capillary. - At arterial end of capillary blood is under high pressure - by contraction of heart muscle

(Blood under high pressure - known as hydrostatic pressure)

4- The hydrostatic pressure will PUSH blood fluid out of the capillaries 
  - Fluid can leave through tiny gaps of the capillary wall
  - Fluid that leaves consists of plasma with dissolved nutrients and oxygen
  - Components such as erythrocytes, platelets…