Immune Organs

Question 1

Primary lymphoid organs

Answer 1

Bone marrow and thymus where lymphocytes are produced

Question 2

Secondary lymphoid organs

Answer 2

Spleen, lymph node, mucosal associated lymphoid tissue

Where antigen meets lymphocytes

Question 3

The thymus

Answer 3

Bi lobed
Medulla - not very stained 
Cortex - highly stained 
No change during infection
Older = fewer new T cells produced so they become less diverse

Question 4

Bone marrow

Answer 4

Red = cells
Yellow = fat
Adults = more fat, fewer cells

Question 5

Lymph nodes

Answer 5

Lymphatic fluid is filtered
T cells in the centre
B on the outside
More B cell production = germinal centres form

Question 6

How do lymphocytes enter lymph node?

Answer 6

High endothelial venules
Lymphocyte rolling
Chemokine receptor on lymphocyte binds to chemokine on HEV
Integrity on lymphocyte has a higher affinity for receptor
Stops

Question 7

Spleen

Answer 7

Filter antigens in blood
White pulp where lymphocytes are
Next to splenic artery = periarterial lymphatic sheath (T) then B region
Without spleen = more infected by encapsulated bacteria

Question 8

Peyers patch

Answer 8

In gut
Germinal centre and follicles
M cell samples antigen and presents it to lymphocytes in the peyers patch

Question 9

Cutaneous immune system

Answer 9

Dendritic cells of skin and mucosa
Lymphocytes
Keratinocytes = detect damage to skin
Macrophages

Question 10

What does selectin do?

Answer 10

Allows weak binding of lymphocyte to HEV

Question 11

Classify T cell receptors

Answer 11

All express CD3
Alpha beta TCR or beta gamma TCR

Of the alpha beta
2/3 express CD4 helper
1/3 express CD8 cytotoxic

Recognise process antigens

Question 12

B lymphocyte markers

Answer 12

CD19 and CD20
Express MCG class II
Antigen presenting cell
Recognise intact antigens

Question 13

Antigen presenting cells and their location

Answer 13

Dendritic - skin and mucosal
B - lymphoid tissue
Macrophages- lymphoid tissue