Exam III Flashcards
What are features of lymph follicles?
Are not enclosed within a capsule
Occur singly or in aggregates
Are sites of B cell localization and proliferation
What distinguishes a primary lymph node from a secondary lymph node?
the presence (secondary) or absence (primary) of a germinal center.
What are the two components of secondary lymph follicles?
germinal center and corona (cortex)
What are CD16 cells also known as?
NK cells
CD8+ T cells
recognize peptide fragments of foreign proteins bound to MHC class I on the surface of cells.
CD4+
recognize peptide fragments of foreign proteins bound to MHC class II on the surface of cells.
What do CD4+ T cells assist in the differentiation of?
CD8+ cells and B cells
What do CD8+ cells release?
perforins and fas ligand
What molecule stimulates the proliferation of NK cells?
Interleukin-2
What is the most important opsonin?
C3B
Where are high endothelial venules found?
In lymph nodes
What are the functions of high endothelial venules?
They bring blood and lymphocytes from the bone marrow in the lymphnodes.
When T cells enter the thymus, what receptors do they initially have?
CD4 and CD8 (they are double positive).
here are double positive T cells found in the thymus?
In superifical regions (subcapsule).
Where are Hassall’s corpuscles found?
in the thymus
What are the results of the complement system?
activation of the membrane attack complex
production of opsonins
Release of chemokines which attract phagocytes to areas of infection or inflammation.
What are the cords of Billroth associated with?
the spleen
Lymph does not circulate through the thymus. Why is this so?
Because there are no afferent lymphatics in the spleen.
What do Hassall’s corpuscles produce, and what is it used for?
thymic stromal lymphopoietin; it is used for stimulation of dendritic cells needed for the maturation of single positive T cells.
Where are double negative T cells found?
the subcapsular arear
Where are double positive T cells found?
the outer cortex
Where are single positive T cells found?
the inner cortex
Where does clonal deletion occur?
the medulla
What is the purpose of the blood thymus barrier?
to prevent antigens in the blood from reaching developing T cells in the thymus
Where are T cells found in the spleen?
surrounding the central artery near the center of the white pulp.
Where in the spleen are B cells activated?
marginal zone
What happens at the Billroth cords?
macrophages destroy worn-out or defective blood cells.
What occurs at the venous sinusoids?
storage sites for healthy red blood cells.
What is the flow of the splenic artery?
splenic artery, trabecular artery, central artery
What space separates the plates of hepatocytes and the endothelium of sinusoids?
space of disse
What is the major duct of the pancreas?
duct of wirsung
What do intercalated ducts in the pancreas secrete?
water and bicarbonate ion
What do acinar cells in the pancreas secrete?
trypsin, chymotrypsin, amylase and lipase
Where are digestive enzymes concentrated and stored in the pancreas?
the golgi
What regulates bicarbonate ion secretion?
secretin
what do A cells secrete?
glucagon
What do B cells secrete?
insulin
What is the function of D cells?
to control levels of insulin and glucagon.
What two types of cells are present at the islets of langerhan?
A cells (glucagon) and B cells (insulin)
What substance acts in response to gastric contents and the pyloric sphincter?
cholecystokinin.
What separates the upper two thirds of the tongue from the lower one third?
sulcus termianlis. It is also a taste bud fund in the V shaped landmark of the tongue.
What are the type of taste buds (papellae) found at the sulcus terminalis?
circumvallate
What is the most numerous of all of the papillae?
filiform papillae
What type of epithelium is present at the gut?
simple columnar with goblet cells.
What are the four layers of the digestive tube?
mucosa
submucosa
muscularis externa
outermost layer (serosa and adventitia)
Where is the myenteric nerve plexus located between?
between two layers of muscle tissue
What are the functions of the muscularis externa?
regulates the size of the lumen
regulates rhythmic movement of the Gi tract
What sympathetics are associated with Meissner’s plexus?
parasympathetics
What is the function of Meissner’s plexus?
regulates local secretions, blood flow and absorption.
What is the function of Auerbach’s plexus?
coordinates muscular activity of the gut wall
In what layer of the digestive tract is Meissner’s plexus found?
submucosa
What are the walls of the alveoli composed of?
Type I and ii alveolar cells
What type of alveolar cells cover the largest surface area?
Type I
What is the function of type II alveolar cells?
they serve as stem cells for type I and type II pneumocytes
What do goblet cells secrete?
mucous
What do neuroendocrine cells release?
catecholamines
What pulmonary cells secrete surfactant?
Clara cells and type II alveolar cells.
What do type II cells phaocytize?
old surfactant
What is the most common type of alveolar cell?
type 1
What is the function of clara cells?
to secrete surface active lipoprotein that prevents collapse of terminal bronchioles during exhalation.
What are dust cells related to?
congestive heart failure
What are the three components of the blood air barrier?
capillary endothelium
pneumocyte epithelitum
basal lamina of both cell types
What are intercalated and principal cells associated with?
the kidney tubules
Where does the digestion of sugars begin?
the mouth
What epitheliu is characteristic of the gut tract?
simple columnar with goblet cells.
