Lymphoid tissues Flashcards
What are primary lymphoid organs?
Where lymphocytes are produced/where lymphopoieses occurs
What are the types of lymphocyte?
B cells, T cells, Natural Killer cells
What type of immunity do B and T cells comprise?
The adaptive immune response
What are the characteristics of adaptive immunity?
Specificity - Vast range of unique T and B cell receptors
Memory - In a secondary encounter, a rapid response will occur
Where are B-Cells and T-Cells produced?
Immature T cells are produced in the bone marrow but then migrate to the thymus to mature
B cells are produced in the bone marrow
What is clonal selection?
Positive selection - Can the T receptor signal
Negative selection - Does the T cell detect self body antigens (if yes, T cell apoptises)
Then all functioning T cells remaining are used
What happens to the thymus with age?
It reduces the output of new T cells due to it reducing in size
What are secondary lymphoid organs?
Where lymphocytes can interact with antigens and other lymphocytes
Where are lymphoid tissues located and how are they connected?
Lymphoid tissues are located all over the body to make sure wherever the pathogen, lymphocytes can quickly detect them
They are connected via the lymphatic system
What is the use of epithelial barriers?
- The first line defence against infection
- Acts as a physical barrier
- Has an extensive lymphatic network
What is the name of the lymph tissue in the gut and what is it’s exact location?
Peyer’s patches
Found below the epithelium of the ileum of the small intestine
How long does it take a naive T cell to recirculate?
24 hours
What occurs in the extravasation of naive T cells?
- Selectins bind to naive T cell
2. The T cell then binds to chemokines on the surface on the endothelial
