Structure and function of lymph node and spleen

Question 1

name primary/central lymphoid structures

Answer 1

bone marrow and thymus

Question 2

name secondary/peripheral lymphoid structures

Answer 2

lymph nodes
spleen
tonsils/adenoids
Peyer’s patch in intestine

Question 3

lymphadenopathy causes

Answer 3

local inflammation
- infection
- others e.g. vaccination, dermatopathic

systemic inflammatory processes
- infection e.g. viral infections
- autoimmune/CT disorders

malignancy
- haematological - lymphoma/leukaemia
- metastatic

others
- e.g. sarcoidosis, Kikuchi’s lymphadenitis, Castlemans Disease; IgG4 related disease

Question 4

how can internal lymph nodes be viewed

Answer 4

radiologically

Question 5

give 2 examples of internal lymph node groups

Answer 5

mediastinal
para-aortic

Question 6

what is the sentinel lymph node

Answer 6

the first lymph node to which cancer cells are most likely to spread
there may be more than one sentinel node

Question 7

what is the sentinel lymph node identified by

Answer 7

dye or radioactive isotopes

Question 8

afferent lymphatics penetrate the capsule (connective tissue surrounding the node) and drain into ________ ______

Answer 8

subcapsular sinus

Question 9

flow of lymphatics (6 points)

Answer 9

• Node is surrounded by connective tissue CAPSULE
• AFFERENT LYMPHATICS penetrate the capsule and drain into SUBCAPSULAR SINUS
• Lymph from subcapsular sinus percolates THROUGH THE NODE
• Lymph enters MEDULLARY CORDS and SINUSES
• Sinuses merge at HILUM and form EFFERENT LYMPHATICS
• Lymph rejoins extranodal lymphatic circulation

Question 10

lymphangitis

Answer 10

inflammation of your lymphatic vessels

Question 11

what are the 3 important regions of lymph node

Answer 11

cortex
paracortex
medulla

Question 12

lymph node cortex

Answer 12

Nodules of B lymphocytes arranged in follicles (primary / secondary)

Question 13

lymph node paracortex

Answer 13

• Mainly T lymphocytes
• Forms the interfollicular tissue which surrounds follicles and extends out and merges with medulla

Question 14

lymph node medulla

Answer 14

Cords and sinuses draining into hilum

Question 15

what cell populations are in lymph nodes

Answer 15

• B cells
• T cells
• Mononuclear phagocytes (macrophages), antigen presenting cells, and dendritic cells
• endothelial cells

Question 16

CD20 is a __-cell marker

Answer 16

B

Question 17

CD3 is a __-cell marker

Answer 17

T

Question 18

two types of follicles in a lymph node

Answer 18

primary
secondary

Question 19

primary follicles in lymph node

Answer 19

Small quiescent lymphocytes
Unstimulated
No germinal centre

Question 20

secondary follicles in lymph node

Answer 20

Activated follicles
Reactive
Germinal centre

Question 21

what are follicular dendritic cells

Answer 21

specialised antigen presenting cells in the follicle.
they are mesenchymal and form meshworks through the germinal centre

Question 22

in a follicle, antigen-antibody complexes are captured by _________ _________ ______(FDCs)

Answer 22

follicular dendritic cells

Question 23

in lymph node follicles, do B cells divide/clonal expansion in the light or dark zone

Answer 23

dark

Question 24

centroblast

Answer 24

proliferating B cell in dark zone of follicle in lymph node

Question 25

what will centroblast proliferate into

Answer 25

centrocyte

Question 26

positively selected B cells go one of 2 ways:

Answer 26

Reenter dark zone and keep proliferating (and expressing cMyc to regulate GC formation) Differentiate into plasma cells Differentiate into memory B cells

Question 27

what is a centrocyte

Answer 27

B cell in light zone Will become either memory B cell or plasma cell

Question 28

what is in the lymph node medulla

Answer 28

Blood vessels Sinuses Medullary cords - Plasma cells, B cells, macrophages Medullary sinuses - Histiocytes, reticular cells - Lymph then drains into efferent vessels

Question 29

Granulomatous lymphadenitis

Answer 29

there are aggregates of histiocytes. there is a wide differential diagnosis, e.g. sarcoidosis

Question 30

sarcoidosis

Answer 30

A granulomatous condition. Systemic disease, requires clinical correlation Sarcoid like reactions can also appear similar May mask malignancy in a lymph node

Question 31

granulomatous inflammation - when caseous necrosis is present what are we thinking?

Answer 31

Infectious cause (Mycobacterial) until proven otherwise (TB bascially)

Question 32

what does generalised lymphadenopathy suggest

Answer 32

a systemic inflammatory / immunological process or widespread malignancy

Question 33

what are lymphomas

Answer 33

Malignant tumours derived from cells of the immune system

Question 34

what is the most common form of lymphoma

Answer 34

non hodgkins lymphoma

Question 35

what is the most common form of non hodgkins lymphoma

Answer 35

B cell lymphomas

Question 36

types of non hodgkins lymphoma

Answer 36

B cell T cell

Question 37

hodgkin's lymphoma prognosis

Answer 37

usually very good

Question 38

types of hodgkins lymphoma

Answer 38

classical nodular lymphocyte predominant

Question 39

which is more common - non-hodgkins lymphoma or hodgkins lymphoma

Answer 39

non hodgkins

Question 40

where is the spleen located

Answer 40

Located high in the left upper quadrant of the abdomen

Question 41

spleen - two key aspects: __________ surface and ________ surface

Answer 41

diaphragmatic visceral

Question 42

the spleen is a very vascular organ, true or false

Answer 42

true

Question 43

spleen vascular supply and drainage

Answer 43

supplied by splenic artery (branch of coeliac trunk) and drained by splenic vein (with superior mesenteric vein forms portal vein)

Question 44

splenic rupture (surgical emergency!) causes

Answer 44

trauma a diseased spleen is more prone to rupture