Tissues of the immune system Flashcards
1
Q
What are the tissues of the primary immune system?
A
- Bone marrow
- Ileal Peyers Patch
- Thymus
- Bursa of Fabricus
2
Q
What is the function of bone marrow?
A
- Area where pluripotent stem cells are found
- Origin of T&B lymphocytes
- Site of maturation of B-lymphocytes before export to secondary lymphoid tissue in humans, rabbits & rodents
- Site of some B-cell differentiation to plasma cells
3
Q
What is the function of the Ileal Peyers Patch?
A
- Site of B-cell maturation in most animal species
4
Q
Where is the thymus located?
A
anterior mediastinum, in front of the heart
5
Q
What is the function of the Bursa of Fabricius?
A
Site of B-cell maturation in birds
6
Q
What is the function of the thymus?
A
- Site of extra-medullary T-cell development
- T-cells generate cell-mediated immunity
7
Q
What are the tissues of the secondary immune system?
A
- Encapsulated tissue:
- Spleen & lymph nodes
- Unencapsulated:
- Mucosal lymphoid aggregates
8
Q
What are the 4 types of mucosa-associated lymphoid tissues (MALT)?
A
- Gastrointestinal (GALT)
- Bronchial (BALT)
- Nasal (NALT)
- Conjunctival (CALT)
9
Q
Describe the structure of lymphocytes (T & B cells)?
A
- T or B cells
- little cytoplasm (large nucleus)
- few organelles
- condensed chromatin
10
Q
Describe the structure of lymphoblasts (T & B cells)?
A
- more cytoplasm and organelles
- less condensed chromatin
11
Q
Why do lymphocytes recirculate?
A
To maximise the chance of contact between an antigen & the appropriate responding populations of lymphocytes
12
Q
What is lymphocyte ‘homing’?
A
- In high endothelial venules there is increased turbulence which encourages cells to interact with vessel walls
- Lymphocytes express homing receptors and exit the vessel via diapedesis when there is a match with the vasopressin being expressed by the HEV
