Lymphoid System I and II Flashcards
Pattern Recognition Receptors
host that mediates the microbes and other antigens
What are the pathogen associated molecular patterns on microbes ?
- lipopolysaccharide (LPS)
- Lipoteichoic Acid (LTA)
- Mannans from Yeast
- ds RNA from viruses
What makes adaptive immunity differ from innate ?
- requires lymphocytes
Humoral Immunity
- involves B-cells and antibodies and other serum mediators such
Cellular Immunity
- utilizes killer T- lymphocytes (CD8+) and phagocytes
Both humoral and cellular require what ?
- T helper cells (CD4+) and APC
What types of lymphocytes ?
- B cell
- TH cell : TH1, TH2, TH17
- TC cell
Gut-associated lymphatic tissue (GALT)
- important in primary and secondary
What are the types of lymphoid (lymphatic) nodules ?
- primary lymphoid nodule (follicle)
- Secondary lymphoid nodule (follicle)
Primary Lymphoid Nodule (follicle): small size
- consists of small lymphocytes, with no germinal center
- everything is dark
- No specific action
Secondary Lymphoid Nodule (follicle) : large size
- consist of small lymphocytes in the peripheral zone and large lymphocytes located in the germinal center
Germinal Center
- contains large lymphocytes
- light bc euchromatin, active DNA
What is the happening in the germinal center ?
- B cells into antibody producing plasma cells
How does the germinal center develop ?
- when a lymphocyte that recognized an antigen returns to a primary nodule and undergoes proliferation
Lymphadenitis
swelling of nodes
Why do the lymph nodes enlarge ?
- edema and hyperplasia of lymphatic nodules and their cellular components
What are some common symptoms of acute lymphadenitis ?
- swollen, palpable and tender lymph nodes, fever, chills, general weakness
What are the most common causes of lymphadenitis in the neck region?
- Tonsillitis and Pharyngitis
Peyer’s Patch in the ileum
- single nodule or aggregates
Tonsils
- nodules and partial capsule
lymph node and spleen
- nodules and well developed capsule
What is important about the appendix ?
- is a site for B-cells differentiation into immunocompetent cells
Waldeyer’s Ring
comprises the nasopharyngeal tonsil or adenoid, the paired tubal tonsils
Palatine Tonsil
- many nodules, germinal center
- stratified squamous
- large SA, allows things to get stuck
What are the role of lymph nodes ?
- filters and entraps antigen from lymph and supports the immune response
The Lymph enters via
the afferent lymphatic vessels
The lymph exists via
efferent lymphatic vessels
The outer cortex of the lymph node contains
lymphoid nodules, B-cell zones
The inner cortex
- deep cortex, paracortex
- T cell zones
High Endothelial Venule
- cuboidal epithelium
- receptors for APC + lymphocytes
Where are high endothelial venules found ?
- lymph nodes, tonsils and aggregated or solitary lymph nodules
Where are high endothelial venules not found ?
- NOT in spleen
Reticular Fibers produced by
fibroblasts, type III
What do the reticular fibers support ?
provide supporting framework for various tissues and organs
How are the reticular fibers arranged ?
in mesh like network
Lymphatic Capillaries
- endothelium
- incomplete basal lamina
- anchoring filaments to CT
Where do the lymphocytes enter ?
- right side: right lymphatic trunk
- left side: Thoracic Duct
Functions of Spleen
- filtration of blood
- removal of aged or damaged RBCs, old platelets, and blood-born foreign matter
- Site of immune response ( secondary lymph organ)
- Platelet Storage
Red Pulp
- consists of splenic cords and splenic sinuses
White pulp
- periarterial lymphatic sheath (PALS) (around central artery) : mainly T-cells
- lymphoid nodules: B-cells
Lymphatic Vessels
- efferent only
- present in white pulp
- trabeculae
- capsule
Is red pulp an open system or closed ?
- open system
