Unit 2 Flashcards
What are the primary lymph organs?
thymus and bone marrow
What happens in the primary lymph organs?
lymphopoiesis: differentiation of lymph cells from pluripotent progenitor cells
What are the secondary lymph organs?
lymph nodes, tonsils, adenoids, spleen, mesenteric lymph nodes, peyer’s patch.
What happens in the secondary lymphoid tissues?
lymphoid cells proliferate and differentiate in response to environmental conditions.
What is an AFC?
antibody forming and secreting plasma cell
How do blood vessels bypass the thymus cortex?
via trabeculae
Why do the blood vessels need to bypass the cortex?
to ensure that developing t-lymphocytes do not get exposed to antigens in the blood until they are fully differentiated.
Where are Hassall’s corpuscles located?
in the medulla of the thymus
What arteries supply the thymus?
internal thoracic and inferior thyroid arteries.
Where do the internal thoracic and inferior thyroid arteries enter the thymus?
through the outer capsule and travel directly into the interlobular septa (trabeculae)
What path do the venous and efferent lymphatic drainage in the thymus travel?
along the route of the arteries, outwards.
What is the afferent supply of lymph to the thymus?
there is none
What are the main cellular constituents of the thymus?
thymic lymphocytes and epithelioreticular cells
What do the nuclei of thymic lymphocytes look like compared to epithelioreticular cells?
lymphocytes: small dark-stained nuclei. epithelioreticular cells: large, pale stained nuclei.
What happens to the thymus at onset of puberty?
invloution. thymus decreases in sie, and fat accum is noted in organ.
What cell type is in a lymph node nodule?
B-cells. if they are immunologically challenged, it will have a germinal center.
Where do lymph node arteries and veins enter and leave the node?
in the hilar region
What cell types line high endothelial venules and allow circulating T and B lymphocytes to pass between them?
specialized endothelial cells
From what region do circulating T and B lymphocytes enter the lymphatic fluid from the blood?
high endothelial venules in the paracortical region
What is the name of the lymphoid tissue that is not packaged within a capsule of connective tissue and is distributed as nodules of about 1 mm in diameter in various organs?
mucosal associated lymphoid tissues.
Where are the lymphatic nodules in the lingual tonsil located?
in the dorsum of the posterior of the tongue. forms a ring that encircles the junction between the mouth and pharyngeal cavity.
Where are larger dividing lymphocytes located in MALT?
central in the nodule.
Where is MALT located in the wall of the intestine?
below the layer of epithelial cells
What do lymphocytes from MALT in the intestine produce to protect submucosal regions?
polymeric IgA that can be transported by cells of the epithelial layer into the lumen of the digestive system
What cells are on the blade-like villi of the small intestine?
enterocytes and goblet cells
What are the 3 main functions of the spleen?
- antigen presentation to lymphoid cells
- production of antibodies by plasma cells
- RBC and platelet disposal after mac phagocytosis
What is the spleen missing that the thymus and lymph nodes have?
cortex and medulla.
What makes up the white pulp of the spleen?
lymphocytes- B-cells form nodules in the white pulp
What is in the red pulp of the spleen?
red blood cells
What is an incoming arteriole surrounded by in the spleen?
periarteriolar lymphatic sheath (PALS)
Why is circulation in the spleen called open circulation?
because blood is drained into open spaces of the reticular network that surrounds the sinusoids
How do RBCs reenter the vascular system from the spleen?
squeeze in between endothelial cells or pass through pores.
Which area has the reticular supporting network in the spleen?
red pulp
What are the 3 things that G-CSF does to promote neutrophil growth?
normalize production, increase neutrophil count in all compartments, and prevent infection
What terms refers to a change in WBC differential that results in an increase in the numbers of segs and bands and maybe even metamyelocytes or myelocytes?
left shift
What are the 3 main causes of eosinophilia?
allergies/allergic disorders, parasitic infections, drug rxns (can rarely also be caused by pempigus, tumors, or malignancies, infections like chronic hepatitis)
What are some causes of basophilia?
drug of food hypersenstivity, urticarial(hives), infection/inflammation, myeloproliferative disease (CML, myeloid metaplasia).
What’s the term for neutrophils passing through endothelial junctions?
diapedesis
What are some of the receptors involved in diapedesis?
Sialyl LeX, L-slectin, B2 integrins (CD11b, CD18
What are some of the receptors involved in chemotaxis?
C5a, N-formyl oligopeptides, lipid compounds (LTB, PAF)GM-CSF, IL8, TNF alpha
