lymph node histology

Question 1

Lymphocytes

Answer 1

major cellular component of the immune system, detect and eliminate foreign Ags. Lymphocytes are generated and become mature in primary lymphatic organs (bone marrow and thymus)

From primary lymphatic organs, lymphocytes migrate into tissues where they are poised to carry out their protective mission

If a foriegn Ag should breech the envrionment organism interface, the immune system further protects the organism by continually monitoring body fluids and elimainating foreign Ag detected in those fluids

Secondary lymphatic organs include lymph nodes and spleen

Question 2

secondary lymphatic organs

Answer 2

bone marrow and thymus are the primary lymph organs where the maturation of B and T cells occur
Secondary lymphatic organs where lymphocytes, in response to Antigenic stimuli mount an immune response

in secondary immune cells, B cells differentiate into plasma cells, while T cells further mature to become effector or memory T cells

In lymph nodes B cells are in the periphery (follicles in cortex), T cells and macrophages are in the paracortex and medulla

Question 3

lymph nodes

Answer 3

almost all tissues except CNS, orbit, inner ear, epidermis, cartilage and bone)
drain extracellular fluid from the tissue spaces, and empty the lymph into the venous system
Small, kidney-bean shaped organs whose function is to filter lympoh

The circulation of lymph through a node is as follows: lymph enters the node via afferent lymphatic vessels that penetrate the connective tissue capsule surrounding the node along the convex surface, lymph is released from afferent vessels into the subscapular sinsu and flows thru lymph channels toward the hilus and then the lymph is carried away from the node by efferent lymphatic vessels that leave the convex hilus

Lymph comes into contact with lymphocytes and maacrophages which are attached to stromal fibers

Question 4

Lymphnode histology

Answer 4

At the conves outer surface of the node, there is a subscapsular sinus, darck clusters of darkly staining cells forming lymphoid follicles

Primary lymphoid follicles are uniform in staining intensity and consits mostly of naive B cells
Secondary lymphoid follicles have a lightly staining germinal center surrounded by darker staining mantle zone,
The presence of secondary follicles indicates that B cells have been activated by the presence of a forign Ag in lymph fluid

Question 5

Secondary follicles

Answer 5

B cells with a high affinity for the foreign Af are undergoing clonal expansion and mutation to increase their affinity for the Ag

Between the cortex and medulla of a lymph node is dominated by T cells,

When swollen glands– B cell proliferation