Lymphatic Flashcards
Lymph differentiation
Two types
Antigen independent- primary organs, when cells are marked with CD markers
Antigen dependent- secondary organs
Negative selection- when lymph’s are asked to identify self vs nonself
Gets rid of lymph’s that attack self antigen
Negative vs positive feedback
Negative- when lymph’s must distinguish from self vs nonself, antigen attack means they undergo apoptosis
Positive selection- when activated B cells present their antigen to more th cells, which activate more and more B cells
Cell receptors
B cells- antibody like
IgA family
T cells- CD3 for all
CD4 for Th
CD8 for Tc
Both b and T cells made in
Bone marrow
T cells mature in thymus
B cell maturation
Bone marrow stromal cells produce IL7
Which makes the receptor complex —> IgD and IgAlpha and IgBeta
Negative selection- self vs nonself antigen, gets rid of cells that attack
Antibody functions
Bind to B cells:
IgM- compleMent system
IgD- Diff into plasma cell
Bind to epithelial cells:
IgA- saliva and tear immunity, Apical domain
Bind to macros and neutrophils:
IgG- 85%, G for Gun= cytotoxic
Bind to mast cells and basophils:
IgE- histamEneeee, for allergic reaction
T cell maturation
Mature in thymus
Cortex:
- Enter as “double negative” (no CD markers)
- Marked w somatic recombination to “double positive” (both CD markers)
- positive selection done, MHC1 cells drop CD4 marker, MHC2 cells drop CD8 marker, the other marker is increased in expression!!! Made a “single positive” cell, MORE MADE
Medulla:
T cells made in cortex move to medulla to undergo negative selection
Test to see if cells recognize self vs nonself
Attack self? Apoptosis
Right lymph duct
Thoracic duct
Right- drains UR side of body
Thoracic- drains the rest
Lymph tissue can be?
Three diff types of tissues
Diffuse- Loose, LP
Cells= WBC and lymphocytes
Nodules- Dense tissue, lymph nodule w germinal center
Aggregates of nodules- peyers, appendix, tonsils
Tonsils
Aggregates of nodules type of lymph tissue
Waldeyers ring; palatine, pharyngeal, lingual
Surrounded by strat squamous et
Have DEEP crypts for saliva and antigens to penetrate
Only has efferent vessel bc saliva enter on side without capsule into the crypts, then into lymph nodes
Lymph nodes
Lymph nodes located on head/neck, shoulders and pits, groin , knees and elbows
Arrange like beads on a string
Filter microbes
Have b and T cells
Reticular fibers for framework
Cortex
Paracortex
medulla
Lymph node layers
Cortex- lymph nodules w germinal centers SECONDARY
Paracortex- lymph nodules without germinal center PRIMARY
HEV allow lymph’s in and out
Medulla-
Cords= plasma cells, macros, lymph’s
Sinuses= empty space
High Endothelial Vein
HEV
Not Sim squamous
Cuboidal, in paracortex
90% lymphocytes come through here
Only 10% lymph’s come through afferent vessel
When does a primary follicle become a secondary follicle
After antigen exposure, the germinal center forms and it moves to cortex
Follicle layers
Aka nodules
Mantle- B cells
Inner cortex- T cells
Germinal center- where t and B cells interact, considered B cell zone
