Primary and secondary lymphoid organs Flashcards
What happens in primary lymphoid organs?
development and maturation of lymphocytes, which are adaptive immune cells
What are the 2 primary lymphoid organs?
Bone marrow, Thymus gland
What happens in secondary lymphoid organs?
Mature naive lymphocytes meet pathogens and antigens and initiate an adaptive immune response
Give 3 examples of secondary lymphoid organs?
Tonsils, appendix, adenoids
What and where are adenoids?
Patch of lymphoid tissue at back of nasal passage (back of throat, behind nose)
Secondary lymphoid organ
What are Peyer’s patches?
Organised lymphoid follicles in the distal portion of small intestine
Found in lamina propia and submucosa
Specific layers of mucous membrane that lines tubes
Where are Peyer’s patches found?
Lamina propria: thin connective layer in mucosa
Submucosa: thick, loose connective tissue layer surrounding mucosa
Specific areas of small intestine
Where are Peyer’s patches found in SI?
Ileum (contains 50%), jejunum, duodenum
Where are lymph nodes?
Strategically placed around body
How are pathogens transported to lymph nodes from infected/inflamed peripheral tissues?
Dendritic cells pick up pathogens from inflamed peripehral tissue and migrate to the closest lymph node
Occurs after migration of pathogen with dendritic cells
Where do T lymphocytes migrate to in the lymph node?
Circultating T cells enter lymph node, then chemokines attract T cells to the paracortex
Which vessels are pathogens transported in to lymph nodes?
afferent lymphatic vessels
After pathogen/DC migration
Where do B lymphocytes migrate to in the lymph node?
Circulating B cells enter lymph node, then chemokines attract them to lymphoid follicles in outer cortex
How are T cells activated in the lymph node?
Dendritic cell becomes APC, matches with complementary T cell
T cell will proliferate and destroy pathogen
How does T cell activation and proliferation change lymph node structure?
T-dependent zone enlarged
