Mass Transport in Animals

Question 1

What is Tissue Fluid

Answer 1

Fluid that surrounds cells and tissues

Contains exchange substances that have left the blood plasma

Question 2

What substances stay in the capillary?

Answer 2

Large substances such as erythrocytes (RBCs) and leukocytes (WBCs) aswell as plasma proteins

Question 3

Which substances leave the capillary

Answer 3

Water, glucose, amino acids

Question 4

What is oncotic pressure

Answer 4

The difference between the water potentials

Question 5

How is tissue fluid reabsorbed

Answer 5

In the venule end of the capillary there is high oncotic pressure due to the loss of water

Therefore water re enters the capillary via osmosis through a partially permeable membrane

Question 6

Why do cells need to produce tissue fluid

Answer 6

To produce nutrients and remove waste

Question 7

Define oedema

Answer 7

An accumulation of tissue fluid in the cavities of tissues in the body

Question 8

Describe how tissue fluid is formed and how it is reabsorbed to the circulatory system? (6)

Answer 8

High hydrostatic pressure forces fluid out into the interstital space

Large molecules such as plasma proteins remain in capillary

This leaves a low water potential in capillary

At the venule end there is a high oncotic pressure

so water returns to the capillary via osmosis.

Lymphatic system returns excess fluid to circulatory system.