deck_3459893 Flashcards
Lymph node anatomy
A secondary lymphoid organ many afferentsone or more efferentsEncapsulatedTrabeculae
Lymph node functions
- Nonspecific filtration by macrophages2. Storage of B and T cells3. Immune response activation
Lymph node follicle
B cell localization
Lymph node follicle, outer cortex.
Primary and secondary follicles
Lymph node- Primary follicles
dense and dormant
Lymph node- Secondary follicles
Active, have pale central germinal centers
Lymph node medulla
Medullary cords and sinuses
Lymph node medullary cords
lymphocytes and plasma cells
Medullary sinuses
Reticular cells and macrophages
Lymph node paracortex
T cells. Region of cortex between follicles and medulla. High endothelial venues through which T and B cells enter from blood.
Digeorge syndrome
Lymph node paracortex is not well developed.
Lymph node response to extreme cellular immune response (i.e. viral infection).
Paracortex enlarges
Cells of the medullary cord (of lymph node)
Lymphocytes and Plasma cells
Cells of the medullary sinus (of lymph node)
Macrophages and Reticular cells
Head and Neck lymph drainage
Cervical
Lungs lymph drainage
Hilar
Trachea and esophagus lymph drainage
Mediastinal
Upper limb, breast, skin above umbilicus lymph drainage
Axillary
Liver, stomach, spleen, pancreas, upper duodenum lymph drainage
Celiac
Lower duodenum, jejunum, ileum, colon to splenic flexure lymph drainage
Superior Mesenteric
Lower rectum to anal canal (above pectinate line), bladder, vagina (middle third), prostate lymph drainage
Internal Iliac
Colon from splenic flexure to upper rectum lymph drainage
Inferior mesenteric
Testes, ovaries, kidneys, and uterus lymph drainage
Para-aortic
Anal canal (below pectinate line), skin below umbilicus (except popliteal territory) lymph drainage
Superficial Inguinal
Dorsolateral foot, posterior calf lymph drainage
Popliteal
Right lymphatic duct
Drains right side of body above diaphragm
Thoracic duct
drains everything else into junction of left subclavian and internal jugular veins
Sinusoids of spleen
- Long, vascular channels in ‘red pulp’2. Fenestrated “barrel hoop” basement membrane3. Macrophages found nearby
Where are T cells in the spleen found?
Periarterial lymphatic sheath (PALS) within the ‘white pulp.’
Where are B cells in the spleen found?
Follicles within the ‘white pulp.’
Marginal zone of the spleen
- between the red and white pulp2. contains APCs and specialized B cells3. Where APCs capture blood-borne antigens for recognition by lymphocytes
What do macrophages in the spleen do?
Remove encapsulated bacteria
Examples of splenic dysfunction
Postsplenectomy Sickle cell disease
Splenic dysfunction
Decreased IgM →↓complement activation →↓C3b opsonization →↑susceptibility to encapsulated organisms
Encapsulated organisms
- Streptococcus pneumoniae2. Haemophilus influenzae type b3. Neisseria meningitidis4. Escherichia coli5. Salmonella spp.6. Klebsiella pneumoniae7. Group B Streptococci(SHiNE SKiS)
Postplenectomy problems
- Howell-Jolly bodies2. Target Cells3. Thrombocytosis (loss of sequestration and removal)4. Lymphocytosis (loss of sequestration)
Thymus function
T cell differentiation and maturation (it’s encapsulated)
Thymus embryology
Derived from the third pharyngeal pouch THymus- THird
Cortex of thymus
Dense with immature T cells
Medulla of thymus
Pale with:1. Mature T cells2. Hassall corpuscles (epithelial reticular cells)
Where do B cells mature?
Bone Marrow
