Lymphatic system

Question 1

What are the 4 primary functions of the lymphatic system?

Answer 1

Tissue drainage

Return of plasma and plasma proteins

Transport of absorbed fat from the gut

Immunity

Question 2

Why is lymph needed for drainage of interstitial fluid, and capillaries are not utilised?

Answer 2

Capillary venules do not allow re-entry of fluid, whereas the lymphatic capillaries have overlapping endothelial cells, that allow this

Question 3

Aside from lymph fluid and plasma proteins, what can be found in lymph capillaries?

Answer 3

Lymphocytes

Fats

Question 4

What structural feature in the lymphatic ensures unidirectional flow?

Answer 4

Valves

Question 5

Describe how infection leads to increased flow throw the lymphatic system, and a greater immune response at the lymph nodes.

Answer 5

Infection means an accumulation of proteins in the extracellular space

Fluid flows into these spaces via osmosis

More extracellular fluid = more flow into lymph

More antigens in lymph = more presented in the nodes = more phagocytosis

Question 6

What is secondary lymphoid tissue?

Answer 6

Lymph nodes

Question 7

Where are most lymph nodes found grouped together?

Answer 7

At the bases of major arterial trunks

Question 8

Describe the structure of a lymph node.

Answer 8

Mass of lymphatic tissue surrounded by fibrous capsule

Contains trabeculae and follicles (germinal centres)

Each node has afferent and efferent lymphatic vessels

Each node has it’s own blood supply (vein and artery)

Capillaries innervate the tissue

Question 9

Where are most lymphocytes found in lymph nodes?

Answer 9

Germinal centres - follicles in the lymphoid tissue of the node

Question 10

Give the 3 palpable areas of lymph nodes.

Answer 10

Axillary

Inguinal

Cervical

Question 11

What are sentinal nodes?

Answer 11

The first few nodes that drain an organ/tumour

Question 12

What type of tumours can lymph nodes get:

Primary or secondary?

Answer 12

Both

primary - lymphomas

secondary - metastasis from other sites

Question 13

What happens to the lymph nodes in inflammatory hyperplasia?

Answer 13

They become enlarged

Question 14

Aside from cancer and Inflam. hyperplasia, what other pathologies can happen to lymph nodes?

Answer 14

Glandular fever and tuberculosis

Question 15

All lymphatic drainage ends up in two drainage routes. What are these called?

Answer 15

Thoracic duct - (main)

Right lymphatic duct - (right side of head, right arm, right peck and surrounding areas)

Question 16

What is highly concentrated in lymph fluid when it returns from the small intestine?

Answer 16

Fats absorbed from our food

Into lacteals

Question 17

Where does the fat absorbed into the lymph go?

Answer 17

Superior vena cava

Then to the liver

Question 18

What is the largest organ that is directly involved with the lymphatic system?

Answer 18

Spleen

Question 19

The histology of the spleen looks similar to another structure in the body. What is it, and how are they similar?

Answer 19

Similar to lymph nodes

Germinal centres have high concentrations of lymphocytes (in LN). In the spleen, white pulp areas have high concentrations of lymphocytes also.

Question 20

What is the anatomical difference between para-aortic and pre-aortic lymph vessels?

Answer 20

Pre-aortic - anterior to aorta

Para-aortic - posterior to aorta

Question 21

What are the only organs/tissues in the body without lymphatic drainage?

Answer 21

Cartilage, the eyes, inner ear, brain and spinal cord