tuesday test lymphoid2 Flashcards
(37 cards)
What kind of immunity is lymphoid tissue?
Adaptive Immunity - specific pathogen and defends against that specific pathogen, unlike a generalized like with Innate
where are B- and T-lymphocytes activated?
secondary lymphoid tissue, such as
- lymph nodes
- spleen
- tonsils (= MALT) etc.
Adaptive Immunity components?
- Antigen Presenting Cells
- Cytotoxic T-cells
- Plasma cells
- Memory cells
All of these are lymphocytes
Primary lymphoid organs? Their function?
they mature lymphocytes.
– Thymus & bone marrow
Secondary lymphoid structures? Their function?
- Lymph nodes
– Spleen
– Mucosa associated lymphoid tissues (MALT) - Tonsils
- Wall of digestive tube (i.e. gut =GALT)
- Peyer’s patches
- Wall of respiratory tubes (bronchial =BALT)
lymphocytes are activated and memory lymphocytes produced
reticular fibers job?
form walls of 3-D pockets
job of macrophages in lymphoid tissue?
eat pathogens and are APCs for lymphocyte activation.
most infectious organisms are destroyed by lymphocytes, neutrophils & Macs.
Dendritic cells job in lymphoid tissue?
super APCs; migrate in from all over body
High-endothelial venules (HEV) job?
where lymphocytes leave blood & enter lymphoid tissue
Do memory cells form in lymphoid tissue?
Most memory lymphocytes are formed, for long-term immunity
What are nodules (follicles)?
Are a dense collections of lymphocytes – a mixture of B and T cells. - vast majority is B cells
What is the difference between primary and secondary nodules?
- Primary - Accumulation of B cells resulting from antigen-driven B cell proliferation
- Secondary - Actively producing clonal B cells (plasma and memory); activated B cells, exit as a plasma cell or reside as memory cell = Germinal center
How do GC look like and where are they located? What are they?
more cytoplasm (“clock face”) than in the typical, small lymphocytes
they are located in 2° Lymphoid Nodule
Dividing B cells in GC
What is Lymphatic System?
Constitute a series of in-line filters in the system
Enclosed environment in which T and B cell encounter antigen
• Place of Plasma cell differentiation – Antibody production
How many lymph nodes are there in the body? Where?
450 Lymph Nodes
- Axilla
- Groin (inguinal )
- along major vessels of
– Neck (cervial)
– Thorax (thoracal)
– Abdomen (mesenteric)
3 structural components of a lymph node?
Outer cortex
Para cortex
Central medulla
outer cortex job?
- – Sub-capsular sinus receives lymph fluids;
- – Branches into cortical sinus;
Delivers lymph fluid to immune cells located in cortex region.
- – Nodules (GC)
• B cell rich area • Antigen can be trapped by APC
what is happening in Para cortex?
– T cell rich area (activation of cytotoxic T cells)
– circulating T & B cells enter from blood stream via HEV (High endothelial venule)
Central medulla function?
– Medullary cord • T & B cells and plasma cells
– Medullary sinuses • last lymph filter (contains macrophages)
• Converge with efferent lymph vessel
Types of cells present in the three compartments of a lymph node?
outer cortex - mostly B cells, some Th, Macrophages
Para cortex - T cells
Central medulla - T cells, B cells (activated), plasma cells, macrophages
How do lymph nodes destroy pathogens?
- Macrophages eat pathogens in sinuses → then can present Ag to T cells in pericortex.
- Other pathogens leak from sinuses into the nearby nodules and are destroyed there by NK and cytotoxic T cells
Example of MALT? what kinds? What is their job?
Tonsils
Several sets: main one is palatine tonsil (object of most infections and of tonsillectomies), adenoid tonsil and lingual tonsil.
• Tonsils sample antigens from the food we swallow and air we breathe.
they make lots of memory lymphocytes for long-term immunity
How does palatine tonsillectomy happen?
• Palatine tonsil has a capsule, and a surgeon cuts just under the capsule to remove this tonsil during tonsillectomy.
Palatine tonsil structure?
Epithelium is thrown into crypts (folds) that gather the pathogens and antigens.
- These invaders work their way into the underlying lymphoid tissue and are destroyed.
- Crypts actively invite infection, but recall that this sampling builds up lots of memory lymphocytes to improve immunity throughout life.
