Lymphoid_Tissue_and_Lymphatics_Final.pptx

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1. Lymphoid Tissue and Lymphatics in the Orofacial Region Seminar Presentation

2. Introduction to the Lymphatic System The lymphatic system is crucial for fluid balance, immune defense, and fat absorption. It includes: Lymph: A clear fluid containing white blood cells. Lymphatic Vessels: Transport lymph throughout the body. Lymph Nodes: Filter lymph and trap pathogens. Lymphoid Organs: Include tonsils, spleen, etc.

3. Types of Lymphoid Tissues Lymphoid tissues are categorized into primary and secondary types: Primary Lymphoid Organs: Bone marrow and thymus. Secondary Lymphoid Organs: Lymph nodes, spleen, MALT.

4. Development of Lymph Nodes and Lymphatics Lymph nodes and lymphatic vessels develop embryologically to form a network essential for immune function. Lymphatic endothelial cells originate from venous endothelium. Lymph sacs form and develop into lymph nodes and vessels.

5. Functions of the Lymphatic System The lymphatic system has three main functions: Fluid Balance: Returns interstitial fluid to the blood. Immune Response: Filters pathogens and initiates immune responses. Lipid Absorption: Absorbs lipids from the intestines.

6. Lymph Nodes Anatomy Lymph nodes are small, bean-shaped structures that filter lymph and support immune function. Cortex: Contains lymphoid follicles with B cells. Paracortex: Rich in T cells. Medulla: Contains macrophages and plasma cells.

7. Microscopic Structure of Lymph Nodes Lymph nodes have a detailed microscopic structure: Cortical Area: B cells and follicular dendritic cells. Paracortex: Houses T cells and dendritic cells. Medulla: Plasma cells secreting antibodies.

8. Blood Vessels of Lymph Nodes Lymph nodes have a blood supply essential for immune function: Arterial Supply: Provides nutrients to lymph nodes. High Endothelial Venules (HEVs): Specialized vessels that allow lymphocytes to enter lymph nodes.

9. Clinical Significance of Lymph Nodes Lymph nodes are indicators of various conditions: Lymphadenopathy: Swollen lymph nodes due to infection or malignancy. Cancer Metastasis: Common sites for cancer spread.

10. Lymph and Rate of Lymph Flow Lymph flow is vital for immune surveillance: Factors: Muscle contractions, breathing, arterial pulsations. Lymphedema: Swelling due to blocked lymphatic flow.

11. Tonsils in the Orofacial Region Tonsils protect against inhaled or ingested pathogens: Lingual Tonsils: At the base of the tongue. Palatine Tonsils: Sides of the throat. Pharyngeal Tonsils (Adenoids): In the nasopharynx.