S9 Lymphatics

Question 1

What is the order of movement through vessels in the lymphatic system from the cells to the vein?

Answer 1

cells to capillaries to trunks to ducts to vein

Question 2

How is the lymph moved around the lymphatic system?

Answer 2

Lymph is propelled by compression by local veins and arteries (lymphagion).

Ducts and trunks have smooth muscle.

It’s a low pressure system

Question 3

Where are lymphatics not found?

Answer 3

Brain

CNS

Question 4

What is the role of the thymus?

Answer 4

The thymus carries out THYMIC CELL EDUCATION (stem cells activated to T cells which activate B cells).

Question 5

Where is the thymus found and what happens to it as you get older?

Answer 5

The thymus is found between the lungs. It shrinks as you get older.

Question 6

What do lymph nodes do and what do they look like?

Answer 6

They filter lymph (afferent and efferent lymphatic vessels).

Look like kidneys

Question 7

Where are lots of lymph nodes found?

Answer 7

Groin
Neck
Armpit

(Think of areas that get infected easily)

Question 8

What is the clinical name for enlarged lymph nodes?

Answer 8

Lymphadenopathy

Question 9

What does the spleen contain?

Answer 9

Red pulp

White pulp

Question 10

What does red pulp do?

Answer 10

Site of haematopoiesis - removal and destruction of old/damaged/abnormal erythrocytes and platelets and stores erythrocytes - filters RBC

Question 11

What does the white pulp do?

Answer 11

Site of immune response - antigen presentation/activation and proliferation of B and T lymphocytes.

Question 12

What is a splenectomy?

Answer 12

Removal of spleen.

You can live without your spleen - bone marrow and liver can carry out haematopoiesis. However increased infection risk by encapsulated bacteria.

Question 13

What is splenomegaly?

Answer 13

Enlargement of the spleen due to infection (localised or systematic)

Question 14

What is lymphoma?

Answer 14

Malignancy of lymphoid tissue

Two types: Hodgkin’s and Non-hodgkin’s.

Question 15

How much lymph is produced each day?

Answer 15

3-4L (it is recycled)

Question 16

Upper right of body…

Rest of body…

Answer 16

…lymph drains into right subclavian vein (or internal jugular vein)

…lymph drains into the left “ “ “

Question 17

Where is the spleen?

Answer 17

Behind (inferior to) the stomach

Question 18

What do the tonsils do?

Answer 18

Prevent ingress of pathogens through nasal/oral routes

Question 19

What do tonsils and vermiform appendix have to increase SA?

Answer 19

Crypts

Question 20

What cells are on the surface epithelia of tonsils? And what do they do?

Answer 20

Microfold cells - present antigens to underlying immune cells

Question 21

Why do tonsils swell?

Answer 21

Due to B and T cell proliferation

Question 22

What is the type of tonsil we’re most interested in?

Answer 22

Palatine tonsil

Question 23

What is in the lymph from the GI tract?

Answer 23

Chyle - white cloudy substance that contains fat and dissolved lipids.

Question 24

What does the appendix do?

Answer 24

Prevents pathogen ingress from GI routes and ileum.

Question 25

Name the lymphatic organs.

Answer 25

``` Tonsils, Thymus, Spleen, Vermiform Appendix, Lymph Nodes, Payer’s patches ```

Question 26

Can you live without a appendix?

Answer 26

Yes, can be removed by appendectomy. You aren’t immunocompromised when it is removed as rest of GI tract has lymph nodes and lymphoid tissue (GALT - gut associated lymphoid tissue).

Question 27

What do Payer’s patches do?

Answer 27

Make T and B cells to fight infection in stomach and contain microfold cells to do so (present antigens to lymphocytes)

Question 28

Where do you find Payer’s patches?

Answer 28

Side of ileum

Question 29

What is the name of the 1st node that metastatic cancer develops?

Answer 29

Sentinel lymph nodes

Question 30

What are primary and secondary lymphoedema?

Answer 30

Primary - congenital (e.g. milroy’s diease) Secondary - due to medical intervention/immobility/parasites/infection (e.g. cellulitis - vessel obstruction)

Question 31

How can sentinel lymph nodes be used in cancer detection?

Answer 31

First lymph nodes to swell. Inject purple dye into this area and can see where cancer has spread to.

Question 32

How do you treat lymphoedema?

Answer 32

There’s no cure, only improvement of symptoms. Can use compression stockings

Question 33

What are the four main functions of the lymphatic system?

Answer 33

1. Fluid balance 2. Transport of fats and fat-soluble vitamins (from digestive system to venous circulation) 3. Defence against pathogens and disease 4. Storage and destruction of aged erythrocytes (spleen)

Question 34

What are germinal centres?

Answer 34

Sites at which mature B cells proliferate. Dendritic cells attract helper T cells which activate B cells which proliferate at germinal centres.

Question 35

What are dendritic cells?

Answer 35

Antigen presenting cells