WVSOM -- Histology

Description:	Immune Systems
Category:	Histology
Created by:	null on 2008-10-31

Question	Answer
Lymph	10% of the tissue that is left behind. usually 1-2 quarts
Immune System	Maintain the fluid environment of the body by producing filtering, and conveying lymph
Thymus	supports the proliferation and programming of the T lymphocyte percursors
T lymphocytes	Cell mediated responses Assist B cells in developing humeral responses to thymus-Dependant antigens
B Lymphocytes	antibody-secreting plasma cells
Thymus 2 parts	cortex medulla
Cortex of Thymus	peripheral region that contains densely packed T lymphocytes suspended in a network of epithelial reticular cells. Training T cells to not go after "self" BASOPHILLIC Site of lymphoblast proliferation to produce smaller, more mature T cells
Medulla of Thymus	Region contains more epithelial reticular cells and fewer T lymphocytes than the cortex. MACROPHATES AND LARGE LYMPHOCYTES Eosinophillic T cells are mature and enter the circulation through post capillary venules or efferent lymphatic vessels
Cortical Epithelial reticular cells	Program which T cells will die and which ones will live and progress to the thymus medulla
Medulla contains more ____________ epithelial cells and fewer _______________ than the cortex	epithelial reticular cells; T lymphocytes
Blood-thymus barrier	blood supply of the thymus enters through the capsule and connective tissue septa
Hassall Corpuscles	formed from type VI epithelial reticular cells and found in Thymus.
What makes the thymus different from otehr lymph tissue	Does not check any lymph from the body. Only EFFERENTS. Can only leave the thymus. No afferent lymphatics or lymph sinuses present No lymphatic nodules present
EBV	only carried in saliva. B lymphocytes may also contain the virus in a state of incomplete replication When B lymphocytes become infected, they are altered permanently and undergo polyconal activation adn proliferation
Involution of the thymus	at puberty, the thymus begins to degenerate, beginning in the cortex
By old age the thymus is almost all _____________.	connective tissue
Lymph Node	lymphoid organs found along lymphatic vessels that filter the lymph for antigens
Convex surface of the Lymph Node	receives afferent lymphatic vessels
Concave surface	contains areterioles and efferent lymphatic vessels
Stroma	reticular fibers structure the cells hang on to
Subcapsular/cortical sinus	where lymph is dropped off to check it to make sure it is ok
Cortex of Lymph Node	Sinusoids Lymphoid Nodule paracortex
Sinusoids	endothelium lined spaces create subcapsular sinuses
Lymphoid nodules	B cells with some T cells and macrophages
Paracortex	mostly T cells
T cells stain	basophillic
Germinal Center	B Cells that are activated to turn into plasma Cells Light staining center
Medulla of lymph node contains	cords with reticular cells and plasma cells. Stain lighter than the cortex
Reed-Sternberg Cells	Look like lacuna in the lymph Diagnostic cells for Hodgkins and other lymph node disease
Spleen	Largest Lymphoid organ Filters blood
Spleen is surrounded by a	capsule
Spleen consists of 2 different kinds of _____________	pulp
2 kinds of pulp	White and red
White Pulp	Sticks with arteries Named for having white blood cells
Red Pulp	Disorganized Associated with Red blood cells
Splenic Artery	enters at the hilum thru connective tissue
Splenic Trabeculae arteries	Branches from the splenic artery. When they enter the splenic pulp they become central arterioles
PWP	Peripheral White Pulp B cells
PALS	T Cells
Divisions of the arteries follow	the white pulp
What makes spleen different form the other lymph tissue	no afferent lympatics or lymph sinues present No cortex or medulla Sophisticated vascular system Lymphoid tissue found in the while pulp
Mononucleosis and the spleen	spleen enlarges becuase it is flooded with atypical lymphocytes. Get lodged in the red pulp as well as teh capsule and trabeculae
Unencapsulated lymphoid nodules	unorganized Named for area it is at Groups of T cells just hanging out Found in loose connective tissue
GALT	Gastrointestinal Associated Lymphatic Tissue
2 zones of unenecapsulated lympohoid nodules	Marginal and germinal center
Marginal Zone	Has memory cells
Germinal Center	Has B cells
BALT	broncial-associated lymphatic tissue
peyer's patches	globs of purple found in ileum setting a stage for immune response if needed
Adenoids	Pharyngeal Posterior wall of nasopharynx covered with ciliated pseudostratified colummnar epithelium