7.6 - Blood, Tissue fluid and Lymph

Question 1

Formation and transport of lymph

Answer 1

It is formed and transported around the body as follows:

1. Some tissue fluid doesn’t re-enter capillaries from tissue fluid.
2. This fluid instead drains into lymph vessels (lymph capillaries) forming lymph.
3. Lymph is transported through lymph vessels by muscle contractions.
4. Lymph is passed through lymph nodes to filter pathogens.
5. Lymph is eventually returned to the blood.

Question 2

Composition of lymph

Answer 2

Lymph has a similar composition to tissue fluid, except:

• Lymph has less oxygen and nutrients.
• Lymph has more fatty acids.
• Lymph has more white blood cells (lymphocytes)

Question 3

Formation of tissue fluid at the venule end of the capillaries

Answer 3

At the venule end of capillaries:

• The hydrostatic pressure is lower.
• Proteins in blood exert a high oncotic pressure, a type of osmotic pressure, in capillaries.
• The water potential is lower in capillaries than in tissue fluid due to fluid loss.
• Some tissue fluid moves back into capillaries by osmosis.

Question 4

formation of tissue fluid at the arteriole end

Answer 4

At the arteriole end of capillaries:

1. A high hydrostatic pressure, exerted by the force of the heart pumping, forces fluid out of capillaries.
2. This forms tissue fluid surrounding body cells.

Question 5

Tissue fluid composition

Answer 5

• Tissue fluid has no red blood cells.
• Tissue fluid has fewer proteins.
• Tissue fluid has fewer white blood cells.

same as plasma apart from the above

Question 6

What is tissue fluid the site of?

Answer 6

the site of diffusion between blood and body cells, providing cells with nutrients and oxygen while removing waste products - helps fight infection as it forms of the immune response

Question 7

what does tissue fluid fill between?

Answer 7

(interstitial fluid) fills spaces between cells (interstitial space),

Question 8

Functions of blood(6):

Answer 8

• Transports oxygen and carbon dioxide.
• Transports nutrients from digestion.
• Transports waste for excretion.
• Transports hormones.
• Transports food from storage.
• Transports clotting factors.

Question 9

What does blood consist of?

Answer 9

• Plasma- Mostly water, transports substances in solution.
• Red blood cells- Carry oxygen.
• White blood cells- Immune cells.
• Platelets- Involved in clotting.