Lymphatic System I Flashcards
…… cells migrate from bone marrow to the thymus gland to mature and become immunocompetent
T-Cells
T-Cells destroy the antigen by using ……. or activating ……… cells
Cytotoxic action (CD8+) B cells
➢ Produce interleukin 2 (IL2), interferon (gamma) and tumor necrosis factor (alpha) ➢ interact with CD8+ cells to destroy intracellular antigens (viruses & microorganisms).
CD4+ Helper Cells (TH1 cells)
➢ Produce IL 4, IL5 , IL10 and IL13
➢ interact with B lymphocytes to destroy extracellular antigens
CD4+ helper cells (TH2 cells)
Immunocompetent B cells activated by
CD4+ T lymphocyte
Natural killer cells attack ….
Virus infected cells and cancer cells
Types of Immune Responses
Innate Response (Non-specific Immunity) Adaptive Response (Specific Immunity)
Which immune response occurs through fast action of neutrophils, macrophages, mast cells & NK cells?
Innate Response (Non- Specific Immunity)
-Do not produce memory cells
Which immune response depends on initial recognition of antigens by B and T cells?
Adaptive Response (Specific Immunity)
Two Types of Adaptive Immune Response
Antibody Mediated Immunity
Cell Mediated Immunity
…… Immunity uses Specific T cells that specialize in cytotoxicity • Granzymes and perforins as an immune response
Cell Mediated Immunity
…….. Immunity uses helper T-cells, B-cells and Plasma cells that cause a release of antibodies that act on invading antigen as an immune response
Antibody Mediated Immunity
Types of Lymphoid Tissue:
Diffuse Lymphoid Tissue
Nodular Lymphoid Tissue
3 Primary Lymphoid Organs
➢ Bone Marrow ➢ Thymus ➢ GALT
3 Secondary Lymphoid Organs
➢ Lymph nodes ➢ Spleen ➢ Tonsils
The following characteristics are associated with which lymphoid tissue: o Initial immune response o Found in lamina propria o Intercepts antigen o No capsule
Diffuse Lymphoid Tissue
Example: MALT (mucosa associated lymphoid tissue)
The following characteristics are associated with which lymphoid tissue:
➢Characterized by nodules / follicles ➢Primary nodule – mainly consists of small lymphocytes ➢Secondary nodule – consist of germinal center(GC)- area where lymphocytes undergo proliferation.
Nodular Lymphoid Tissue
The paler region in Germinal Center (GC) of Nodular lymphoid tissue
Immature lymphocytes (lymphoblasts)
The ………….. region has FDCs-follicular dendritic cells and indicates lymphatic tissue response to antigen.
Germinal Center
The ……….. region consists of small lymphocytes around the GC
Mantle zone or corona
Within in the lymphatic nodule, reticular cells produce…
Reticular Fibers (stroma)
Within in the lymphatic nodule, B-lymphocytes are activated, proliferate, and turn into ……. and …….. cells
Plasma Cells and Memory Cells
Within in the lymphatic nodule, the two Antigen Presenting Cells (APCs) are…..
Macrophages and Dendritic Follicular Cells
Dendritic Follicular Cells and Macrophages within in the lymphatic nodule present which antigens?
MHC I and II molecules
Follicular Dendritic Cells within in the lymphatic nodule contain which molecules?
Harbors Ag-Ab complexes
Lack MHC II
……… interact with helper CD4+ T lymphocytes to facilitate immune responses.
Antigen Presenting Cells (APC’s)
Functions of Macrophages:
- APC
- endocytosis and partial digestion of protein and polysaccharide antigen before they present them on MHC II molecules to help CD4+T cells
- digest pathogenic microorganisms by lysosomal action
- produces multiple cytokines- lymphokines, complement, interleukins, acid hydrolases and lipases
Macrophages, Kuppfer cells, dust cells, Langerhan cells and dendrtic cells (spleen & lymph nodes) are APC of the ……… system
Mononuclear Phagocytic System (MPS)
……… is primary lymphoid organ located in the superior mediastinum.
Thymus
Epithelial Component of the thymus
Epithelial Reticular Cells (ERCs)
…….. run within the thymus to divide tissue as lobules. Each lobule has a cortical cap over portions of highly convoluted but continuous inner medullary tissue.
Trabeculae
Parenchyma of the Thymus:
In Cortex:
- mainly immature T lymphocytes (thymocytes) & ERCs (epithelial reticular cells)
In Medulla:
- mature T lymphocytes & ERCs
…… primary support cells in the cortex.
Epithelial Reticular Cells (ERCs)
Epithelial Reticular Cells (ERCs) form a ……. which is held together by desmosomes
Cytoreticulum
…… ensheath blood vessels in cortex and sequester the developing T cells from blood born antigens.
Epithelial Reticular Cells (ERCs)
ERCs are Characterized by …….
Characterized by continuous capillaries
The thymus cortex are made of:
Cortex of tightly packed lymphocytes and support cells (epithelial reticular cells)
…….. has lower concentration of lymphocytes
Inner Medulla
The Blood Thymus Barrier is only found in the…..
Cortex
Within the Medulla, lymphocytes…..
Differentiate and enlarge
Mature T cells migrate into medullary blood vessels and efferent lymphatics
ERC’s contract into spherical, degenerative masses
Hassall’s Corpuscle
Hassall’s Corpuscles are found only in the ……… and consist of rings of degenerating epithelial reticular cells
Thymic medulla
Disease: Absent Thymus Gland caused by defect in the development of the 3rd & 4th branchial pouches & arches.
DiGeorge Syndrome (22q11.2 Deletion Syndrome)
DiGeorge Syndrome is also called CATCH 22 which stands for…..
Cardiac Anomaly Abnormal Faces Thymic Aplasia Cleft Palate Hypocalcemia
Kidney Shaped Organs that filters lymphatic fluid
Lymph Nodes
………. mounts immune response by recirculation of lymphocytes (route of metastases)
Lymph Nodes
Where arteries and nerves enter and veins and lymphatic vessels leave the node.
Hilum
Afferent lymphatic vessel – drains lymph through …….
Convex margin
…….. in the deep cortex and medulla allow for the transition of lymphocytes from the blood stream to lymph tissue
High Endothelial Venules (HEVs)
The outer cortex of the thymus is mainly composed of ……..
Lymphatic nodules of B-cells
Few T lymphocytes, macrophages, reticular cells, and APCs
Paracortex is the …………..
Area between cortex and medulla) that is primarily composed of T-cells where excess lymph is reabsorbed
……. allow for the transition of lymphocytes from the blood stream to lymph tissue
Paracortex (deep cortex)
Branched cordlike extension of dense lymphoid tissue
Contain primarily B lymphocytes, plasma cells, reticular cells and macrophages
Medullary Cords
Dilated spaces separating medullary cords
Contain lymph, few wandering macrophages
Granulocytes maybe present when lymph node is draining an infected region
Medullary Sinuses
The stroma of lymph node consists of….
- Reticular cells (modified fibroblasts) cytoplasmic extensions cover reticular fibers
- Framework for myeloid (bone marrow) and lymphoid (lymph nodes, spleen) organs
Lymph node stained with ……..
Silver Stain
