Lecture 23: Lymphatic System

Question 1

What is lymph?

Answer 1

Thin fluid that resembles plasma but has lesser protein

Question 2

What is chyle?

Answer 2

Lymph that arises in GI tract containing fats and dissolved lipids

Question 3

How much lymph is produced each day?

Answer 3

3-5 liters

Question 4

What are the 4 lymphatic vessels?

Answer 4

Capillaries, trunks, ducts, veins

Question 5

What are the 5 structures that lymph flows through from the tissue to the vein?

Answer 5

Lymphatic capillary
Lymphatic vessel
Lymphatic node
Lymphatic trunk 
Lymphatic duct

Question 6

What are 2 similarities between lymphatic capillaries and veins?

Answer 6

Low pressure

Valves present

Question 7

What is the difference between veins and lymphatic capillaries?

Answer 7

No cells in lymphatic vessels but cells present in veins

Question 8

What is the cisterna chyli?

Answer 8

Large container of chyle from GI tract

Question 9

What does the lymph from upper right quadrant drain into?

Answer 9

Right lymphatic duct into right subclavian vein

Question 10

Where does the lymph from the rest of the body flow into?

Answer 10

Thoracic duct into left subclavian vein

Question 11

What are the 3 most important lymph nodes?

Answer 11

Neck (cervical)
Groin (inguinal)
Armpit (axillae)

Question 12

What is the structure of lymphatic vessels in lymph nodes?

Answer 12

Multiple afferent lymphatic vessels that enter via convex surface and single efferent lymphatic vessel that leaves via concave hillbilly

Question 13

What is the structure of the lymph nodes?

Answer 13

Multiple nodules that contain immune cells (macrophages, dendritic, B and T cells, plasma cells)

Question 14

What is the main connective tissue fibre in lymph nodes?

Answer 14

Reticular

Question 15

Where are follicular dendritic cells located?

Answer 15

Germinal centers of lymph node

Question 16

What are the 2 functions of follicular dendritic cells?

Answer 16

Antigen antibody complexes adhere to dendritic processes to be presented to T cells

Cause proliferation of B cells, in particular memory B cells

Question 17

How do T and B cells work together?

Answer 17

B cells finds antigen and presents it to T cell, which activates it to be able to produce plasma and memory cells. Plasma cells then produce antibodies that attach to the antigen, then macrophages eats them.

Question 18

What is the structure of blood vessels in lymph nodes?

Answer 18

Feeding artery and draining vein that enter and leave via the hilum

Question 19

What is lymphadenopathy?

Answer 19

Enlarged lymph nodes

Question 20

What are the causes of lymphadenopathy?

Answer 20

1. During infections, germinal centers fill with increasing numbers of lymphocytes causing lymph nodes to swell
2. Cancer metastasize to lymph nodes
3. Lymphoma

Question 21

What are 6 lymphatic organs?

Answer 21

Thymus
Bone marrow
Spleen
Tonsils
Appendix
Payer’s patches

Question 22

Where is the thymus located?

Answer 22

Superior mediastinum

Question 23

What is the structure of the thymus?

Answer 23

Similar to lymph node (cortex medulla and germinal centre) but no hilum

Question 24

What is the function of the thymus?

Answer 24

Thymic cell education - maturation of bone marrow derived stem cells into immunocompetent T cells

Question 25

What is myasthenia crisis?

Answer 25

Inability to swallow due to weakened muscles

Question 26

Where is the spleen?

Answer 26

Inferior to diaphragm, posterior to stomach

Question 27

What is the structure of the spleen?

Answer 27

White pulp made of lymphocytes and red pulp made of erythrocytes

Question 28

What are the 2 types of function of spleen?

Answer 28

Immune and haemopoietic

Question 29

What are 4 immune functions of the spleen?

Answer 29

1. Antigen presentation by APCs 2. Activation and proliferation of B and T lymphocytes 3. Production of antibodies 4. Removal of macro molecular antigen from blood

Question 30

What are the 3 haemopoietic functions of spleen?

Answer 30

Removal and destruction of old, damaged and abnormal erythrocytes and platelets Retrieval of iron from erythrocyte haemoglobin Erythrocyte storage

Question 31

What is a splenectomy?

Answer 31

Removal of spleen

Question 32

What does splenectomy increase the risk of?

Answer 32

Infection by encapsulated bacteria and malaria

Question 33

What is splenomegaly?

Answer 33

Enlargement due to localized infection or systemic infection

Question 34

Where are 2 locations of the tonsils?

Answer 34

Oreo pharynx and nasopharynx

Question 35

What are the 3 tonsils?

Answer 35

Pharyngeal tonsil Palatine tonsil Lingual tonsil

Question 36

What is the structure of tonsils?

Answer 36

Nodules that reside inferior to surface invaginations

Question 37

What are the 3 functions of tonsils?

Answer 37

Prevent pathogen ingress through oral and nasal routes Prevent pathogen ingress through aural route Crypts increase surface area

Question 38

What kind of specialized cells does the surface epithelia of the tonsil have?

Answer 38

Micro fold cells that present antigen to underlying immune cells

Question 39

Where is the vermiform appendix located?

Answer 39

Inferior to and attached to caecum

Question 40

What is the structure of the vermiform appendix?

Answer 40

Nodules reside inferior to surface invaginations and many M fold cells in epithelial surface

Question 41

What are the 3 functions of vermiform appendix?

Answer 41

Prevent pathogen ingress through GI routes Prevent pathogen ingress arriving from ileum Crypts increase surface area

Question 42

Where are Payer’s Patches located?

Answer 42

Inferior to and attached to side of ileum

Question 43

What is the structure of Payer’s patches?

Answer 43

Nodules reside inferior to surface domes and many M fold cells in epithelial surface

Question 44

What is the function of Payer’s patches?

Answer 44

Prevent pathogen ingress through digestion

Question 45

What are the 4 functions of the lymphatic system?

Answer 45

Fluid balance Transport of fat and fat soluble vitamins Defense against invading pathogens and disease Storage of and destruction of aged erythrocytes (spleen)

Question 46

What are sentinel lymph nodes?

Answer 46

First node to receive lymph from area of a primary tumor

Question 47

What are 2 main types of lymphoedema?

Answer 47

Primary and secondary

Question 48

What is primary lymphodema?

Answer 48

Inherited diseases

Question 49

What are 3 examples of primary lymphoedema diseases?

Answer 49

Congenital (Milroy’s disease) Praecox (Meige’s disease)- 2-35 years Tarda (after 35)

Question 50

What causes Milroy’s disease?

Answer 50

Mutated FLT4 gene leading to small or missing endothelial cells in vessel wall

Question 51

What are 5 causes of secondary lymphoedema?

Answer 51

Neoplasia - inflamed pelvic masses infiltrate lymph node Surgery - node involvement Radiotherapy - nodal fibrosis Autoimmune disease - rheumatoid arthritis or eczema Infections - cellulitis (obstruction of vessel), filariasis (parasitic worm)

Question 52

What are the treatments of lymphoedema?

Answer 52

Lympha Press System