Lecture 7 - Lymphoid anatomy Flashcards
What are the two forms of movement immune cells must undergo? [2]
- Movement to a tissue/organ
- Movement within a tissue/organ
How does the immune system raise the chances that rare antigen specific T and B cells will interact with each other? [3]
- Have collections of T-cells and immune cells in site where infection is likely
- Have cells circulate around the body
- Have specialised sites where antigens are captured
Where do B and T cells develop?
Primary lymphoid tissues
List the two organs of the primary lymphoid system. [2]
- Thymus
- Bone marrow
List the three organs of the primary lymphoid system. [3]
- Lymph nodes
- Spleen
- MALT
What is in the lymphoid vessels? [3]
- Lymph fluid
- Lymphocytes
- Tissue dentritic cells
What is the role of dendritic cells once they enter a lymph node?
They present antigens to T-cells to activate them
What do T-cell do once they are activated?
Move from the lymph nodes through efferent vessels
How long does the immune system take to adapt to a new antigen?
4-6 days
What is the role of the cortex of the lymph node?
The main area that B-cells are found
What is the role of the Paracortex of the lymph mode?
The main area that T-cells are found
What is the role of the medulla of the lymph node?
Contains a mix of:
- Plasma
- T-cells
- Variety of cells such as macrophages
What is the role of secondary follicles of the lymph node?
Area where B-cell proliferation is extremely high
What happens to secondary follicles once the infection has been dealt with?
They turn back into primary follicles
True or False? There is no lymph drainage into the spleen.
True
How does antigen get into the spleen?
Through the blood
What tissue allows lymphocytes to leave the bloodstream and enter lymph nodes?
The high endothelial venules
List four types of adhesion molecules that help with lymphocyte migration. [4]
- Selectin
- Ig superfamily
- Integrin
- Mucin-like vasscular addressin
What is the first process of lymphocyte migration?
Selectin driven Rolling
How does selectin driven rolling work?
E-selectin recognises sialyl-Lewis X structures on immune cells
What is the second process of lymphocyte migration?
Firm attachment
How does firm attachment work?
- ICAM-1 and ICAM-2 are induced on vessels
- They bind to CR3 and LFA-1 on leukocytes
- Rolling is stopped
What is the third process of lymphocyte migration?
Extravasation
How does extravasation work?
- Leukocyte crosses the endothelial wall
- Involved LFA-1/CR3
