University:
Texas A&M University
Course:
BIOL 319 | Integrated Human Anatomy and Physiology I
Academic year:

2021
Views:

177

Pages:

58
Author:

agatoary6zt

LYMPHOID TISSUE PART 1 LYMPH NODES AND GUT-ASSOCIATED Objectives Lymph node Describe the structural organization of lymphoid tissue in general and of the thymus, lymph nodes, lymph nodules (follicles) and spleen. Detail how antigens are removed from the lymph and the blood via the sinuses and reticular cells of the lymph nodes and the spleen. Trace the movements of cells and fluid through the lymph node and the spleen. Part 1 Lymph nodes and gut-associated lymphoid tissue Part 2 Spleen and thymus Spleen FUNCTIONS OF THE IMMUNE SYSTEM • PROTECTION AGAINST FOREIGN INVADERS INTO BODY • PRODUCE / PROTECT GERM FREE ENVIRONMENT OF THE BODY EXAMPLES OF IMMUNE RESPONSE • REACTION AGAINST MICROORGANISMS: BACTERIA, VIRUSES, PARASITES Appendix EXAMPLES OF IMMUNE RESPONSE • REACTION AGAINST MICROORGANISMS: BACTERIA, VIRUSES, PARASITES • REACTION AGAINST TUMOR CELLS Appendix EXAMPLES OF IMMUNE RESPONSE • REACTION AGAINST MICROORGANISMS: BACTERIA, VIRUSES, PARASITES Appendix • REACTION AGAINST TUMOR CELLS • ALLERGIC REACTIONS: HAY FEVER, POISON IVY EXAMPLES OF IMMUNE RESPONSE • REACTION AGAINST MICROORGANISMS: BACTERIA, VIRUSES, PARASITES Appendix • REACTION AGAINST TUMOR CELLS • ALLERGIC REACTIONS: HAY FEVER, POISON IVY • AUTOIMMUNE REACTION: ARTHRITIS, TYPE I DIABETES EXAMPLES OF IMMUNE RESPONSE • REACTION AGAINST MICROORGANISMS: BACTERIA, VIRUSES, PARASITES Appendix • REACTION AGAINST TUMOR CELLS • ALLERGIC REACTIONS: HAY FEVER, POISON IVY • AUTOIMMUNE REACTION: ARTHRITIS, TYPE I DIABETES • GRAFT REJECTION TYPES OF IMMUNE RESPONSE •ANTIBODY - MEDIATED GLYCOPROTEINS RECOGNIZE AND BIND TO ANTIGENS TYPES OF IMMUNE RESPONSE •ANTIBODY - MEDIATED GLYCOPROTEINS RECOGNIZE AND BIND TO ANTIGENS •CELL - MEDIATED SPECIFICALLY ACTIVE CELLS RECOGNIZE CELL - BOND ANTIGENS TYPES OF IMMUNE RESPONSE •ANTIBODY - MEDIATED GLYCOPROTEINS RECOGNIZE AND BIND TO ANTIGENS •CELL - MEDIATED SPECIFICALLY ACTIVE CELLS RECOGNIZE CELL - BOND ANTIGENS T-cells: primary defense against intracellular pathogens, cell-mediated response B-cells: primary defense against extracellular pathogens, transform into plasma cells that produce antibodies for antibody-mediated response ROLES AND SPECIFIC ACTIONS OF ANTIOBODIES IN IMMUNITY COMPLEMENT - MEDIATED LYSIS OPSONIZATION - PROMOTE PHAGOCYTOSIS TOXIN NEUTRALIZATION PREVENTION OF MICROBIAL BINDING TO MUCOSAL SURFACE VIRUS NEUTRALIZATION - INTERFERES WITH CELL PENETRATION DEGRANULATION OF MAST CELLS LIFE CYCLE OF LYMPHOCYTES FETAL ORGANS BONE MARROW PRIMARY LYMPHOID ORGANS (ANTIGEN INDEPENDENT DEVELOPMENT) - THYMUS - T LYMPHOCYTES - BONE MARROW - B LYMPHOCYTES LIFE CYCLE OF LYMPHOCYTES FETAL ORGANS BONE MARROW PRIMARY LYMPHOID ORGANS (ANTIGEN INDEPENDENT DEVELOPMENT) - THYMUS - T LYMPHOCYTES - BONE MARROW - B LYMPHOCYTES SECONDARY LYMPHOID ORGANS (ANTIGEN DEPENDENT DEVELOPMENT) • LYMPH NODES • LYMPHOID NODULES • SPLEEN Lymphoid organs Organ Characteristics Structure Lymph nodes • • • • Filters lymphatic fluid Present where small lymphatics converge Contain many reticular cells APCs present antigen to T and B lymphocytes • Post-capillary high endothelial venules • Dense irregular capsule (Type I collagen) • CT trabeculi extend from capsule inwards to partially divide interior • Subcapsular sinus • Primary nodules – immunologically inactive, no germinal center • Secondary nodules – active with germinal center Spleen • Filters blood and supports lymphocyte differentiation • Dense irregular CT capsule • White pulp • Immune component • PALS – periarteriolar lymphatic sheaths • Red pulp • Dense reticular fiber network • Filters blood Thymus • Lymphoepithelial organ • Atrophies at puberty, fully developed at birth • Proliferation and differentiation of T lymphocytes • Blood-thymus barrier • • • • Irregular CT capsule Incomplete subdivisions into lobules Dense outer cortex & loose medulla Unique characteristic: Hassall’s (thymic) corpuscles LYMPH NODE 44 Hilum = single site for blood entry and exit Lymph node Efferent lymphatic duct 44 44 Lymph node Afferent lymphatic duct 116 Efferent lymphatic duct Both afferent and efferent lymphatic vessels characterize lymph nodes. 116 Slide 44: Lymph Node Medullary sinus Medulla Medullary cords Cortex lymph node follicles Germinal center Trabeculae Capsule Subcapsular sinus LYMPH NODES - FILTRATION OF LYMPH BASIC STRUCTURE - RETICULAR FRAMEWORK LYMPH NODES - FILTRATION OF LYMPH BASIC STRUCTURE - RETICULAR FRAMEWORK LYMPH NODES - FILTRATION OF LYMPH BASIC STRUCTURE - RETICULAR FRAMEWORK Slide 45: Lymph node (reticulum silver stain) Lymph node with reticular stroma Reticular cells Type III collagen The reticular fiber stroma functions as the structural framework of lymph organs. Slide 44: Lymph Node Small lymphocytes in cuff Lymph node follicle (nodules) with germinal center and cuff Lymph nodes have germinal centers to produce T and B lymphocytes against the specific antigen each had encountered in this lymph node. Medium lymphocytes in germinal center LYMPH NODES - FILTRATION OF LYMPH CORTEX • FOLLICLES - B LYMPHOCYTES • PERIFOLLICULAR - T LYMPHOCYTES Lymph node follicle 1. Germinal center 2. Lymphocyte 3. Reticulum cell Lymph node follicle 1. Germinal center 2. Lymphocyte 3. Reticulum cell LYMPH NODES AND LYMPHOID TISSUE Cord Blood sinus Lymph sinus Lymphocytes in cortex LYMPH NODES AND LYMPHOID TISSUE Cord Blood vessel Macrophages containing debre in cords Lymph sinus Lymph sinus 19754 19754 Lymph sinus in lymph node Cord Cord Cord LYMPH NODES AND LYMPHOID TISSUE LYMPH FLOW Parafollicular region Parafollicular region Parafollicular region High endothelial cells of a venule Parafollicular region LYMPH NODES AND LYMPHOID TISSUE LYMPHOCYTE CIRCULATION • HIGH ENDOTHELIAL VENULES RECEPTORS FOR T&B CELLS ONLY • ONE-WAY TRAFFIC LYMPH NODES AND LYMPHOID TISSUE LYMPHOCYTE CIRCULATION HIGH ENDOTHELIAL VENULES RECEPTORS FOR T&B CELLS ONLY ONE-WAY TRAFFIC Slide 44: Lymph Node High endothelial venule - Macrophage Reticular cell Plasma cell High endothelial venule - High endothelial venule High endothelial cells of a venule High endothelial cells of a venule High endothelial cells of a venule High endothelial venules have receptors for T and B lymphocytes and allow: • Enable naïve lymphocytes to move into of lymph nodes from the blood to find it’s unique antigen • Entry point for 90% of lymphocytes into lymph nodes others enter through afferent lymph vessels All lymphocytes inside the node leave via the efferent lymph vessel. Blood flow • Artery > arteriole > capillary around lymphatic nodule > postcapillary high endothelial venule (T & B lymphocyte receptors) > venule > vein Lymph flow • Afferent lymphatic vessels (many) > subcapsular sinus > trabecular (cortical) sinus > medullary sinus > efferent lymphatic vessel INDUCTION OF RESPONSE •PERIPHERAL ORGAN NEEDED TO GET ANTIGEN AND RESPONSIVE CELL TO INTERACT • LYMPHOCYTE RECIRCULATING • APPROPRIATE CONTEXT RECYCLING OF LYMPHOCYTES THROUGH LYMPH NODES High endothelial cells of a venule LYMPH NODES – FILTRATION OF LYMPH TO ALLOW POTENIALLY ACTIVE LYMPHOCYTES TO SEE/RESPOND TO ITS ANTIGEN IF PRESENT IN THE LYMPH. An infected (stimulated) lymph node would be swollen with leukocytes. Summary of Lymph Nodes BASIC STRUCTURE • LYMPHATIC VESSELS • VASCULATURE • RETICULAR FRAMEWORK CORTEX • FOLLICLES - B LYMPHOCYTES • PERIFOLLICULAR - T LYMPHOCYTES MEDULLA • CORDS • SINUSES Gut-associated lymphoid tissue Slide 62: Terminal ileum Peyer’s patches Germinal center Peyer’s Patch M (microfold) cells Simple columnar epithelium M cells in the gut The function of the M [microfold]) cells is to transport (present) organisms and particles from the gut lumen to immune cells across the epithelial barrier. PEYER PATCHES 204 PEYER PATCHES in the human appendix 145 Fundic stomach Esophagus and trachea, monkey Tonsil Slide 46: Palatine tonsil Lymph nodules of tonsil Tonsillar crypts Nonkeratinized stratified squamous epithelium of tonsillar crypt Slide 52: Tongue (lingual tonsil) Scattered nodules Tonsil 419 419 Tonsil If a patient had a tumor on the posterior third of their tongue, the lingual lymph tonsils (situated along surface of the posterior third of the tongue) would need to be check for metastasis.

Lymphoid Tissue Part 1

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