Lymphatics

Question 1

Describe the structure of capillaries:

Answer 1

Thinner walls
Numerous and highly branched
Narrow diameters
Narrow lumen
Spaces between endothelium

Question 2

What is the reason for capillaries having thin walls?

Answer 2

Decreases diffusion distance for gases

Question 3

What is the reason for capillaries being numerous and highly branched?

Answer 3

Large surface area for exchange of gases

Question 4

What is the reason for capillaries having spaces between endothelium?

Answer 4

So white blood cells can pass through

Question 5

What is the reason for capillaries having a narrow lumen?

Answer 5

So red blood cells are squashed against the side of the capillary, decreasing the diffusion distance for gases

Question 6

How much interstitial fluid is generated daily from capillary filtration?

Answer 6

3 litres

Question 7

What are the constituent parts of the lymphatic system?

Answer 7

Conducting system

Lymphoid tissue

Question 8

What is the role of lymphatic capillaries?

Answer 8

To collect interstitial fluid created from capillary flitration

Question 9

What is the structure of a lymphatic capillary?

Answer 9

Blind-ended, bulbous tubes lined with endothelial cells

Question 10

What is the function of uni-directional valves in the lymph conducting systems?

Answer 10

They prevent the backflow of lymph

Question 11

What causes lymph to move through the conducting system?

Answer 11

Contraction of smooth muscle

Question 12

What happens to lymph at the lymph nodes?

Answer 12

Bacteria and foreign material is removed by phagocytosis

Question 13

What do lymph capillaries merge into?

Answer 13

Collecting lymph tubes

Question 14

Describe the structure of lymph collecting tubes:

Answer 14

Smooth muscle and Uni-directional valves

Question 15

Where is lymph collected from and by what is it collected?

Answer 15

Collected by lymph capillaries from the interstitial space

Question 16

Describe the passage of lymph through the lymphatic system:

Answer 16

Collected in lymphatic capillary
Merge into collecting vessel
Afferent lymphatics take to lymph node
Through thoracic duct
Into subclavian vein

Question 17

What is meant by the term afferent lymphatic?

Answer 17

Uni-directional

Question 18

Where does lymph re-enter the circulatory system?

Answer 18

Subclavian vein

Question 19

What is the role of the lymphatic conducting system?

Answer 19

Carries lymph to the nodes and back into the bloodstream

Question 20

Lymph nodes are considered as what type of lymphoid tissue?

Answer 20

Secondary

Question 21

The thymus and bone marrow are considered as what type of lymphoid tissue?

Answer 21

Primary

Question 22

What is oedema?

Answer 22

Swelling in the tissues due to excess fluid in the interstitial space

Question 23

What is kwashiorkor?

Answer 23

A malnourished person does not receive enough protein, therefore, osmotic potential is decreased and less water is pulled into blood capillary. This excess tissue fluid causes a ‘puffed’ belly effect

Question 24

What can cause oedema?

Answer 24

When the rate of capillary filtration is greater than the rate of lymphatic drainage

(Therefore, very fast filtration or dysfunctional drainage)

Question 25

What are secondary lymphoid organs of the body?

Answer 25

Lymph nodes, Payers patches, Tonsils and Adenoids, maintain mature naïve lymphocytes and initiate acquired immune response, sites of lymphatic activation

Question 26

Why might capillary filtration be increased?

Answer 26

An osmotic pressure difference and the capillary hydrostatic pressure

Question 27

What is elephantiasis?

Answer 27

Where nematode worms are present in the lymphatic vessels causing lymph to build up

Question 28

What are primary lymphoid organs of the body?

Answer 28

Thymus and Bone marrow, involved in production and early selection of lymphocytes, generate lymphocytes from immature cells