EX 35 Pre-Lab Lecture

Page 1: Overview of the Lymphatic System

• Key Components:

  • Cervical Lymph Nodes: Filter lymph from head and neck.

  • Mammary Gland Lymphatics: Drain lymph from breast tissue.

  • Cisterna Chyli: Origin point for thoracic duct; collects lymph from lower body.

  • Lumbar Lymph Nodes: Drain lymph from lower back.

  • Pelvic Lymph Nodes: Filter lymph from pelvic organs.

  • Lower Limb Lymphatics: Drain lymph from legs.

  • Thoracic Duct: Main lymphatic vessel, drains lymph into blood system.

  • Thymus: Site of T cell maturation.

  • Axillary Lymph Nodes: Filter lymph from upper limbs and breast.

  • Spleen: Filters blood and produces immune responses.

  • Upper Limb Lymphatics: Drain lymph from arms.

  • Inguinal Lymph Nodes: Drain lymph from groin area.

Page 2: Learning Outcomes

• Functions of Lymphatic Systems:

  • Understand and state the major functions.

  • Name components and compare functions with the blood vascular system.

• Formation and Composition:

  • Discuss how lymph is formed and transported through vessels.

Page 3: Learning Outcomes

• Immune Response Components:

  • Differentiate between B cells and T cells.

  • Describe lymph node structure and function.

  • Identifying locations of T cells, B cells, and macrophages in lymph nodes.

Page 4: Learning Outcomes

• Lymphatic Organs:

  • Micro-anatomical features of the spleen and tonsils.

  • Antibody structure and subclasses.

  • Differentiate between antigens and antibodies.

Page 5: The Lymphatic System Overview

• Components:

  • Lymphatic Vessels: Network for transport.

  • Lymphoid Tissue: Immune response initiation.

  • Lymph Nodes: Filter harmful substances.

  • Tonsils: Fight infections.

  • Thymus Gland & Spleen: Key immune organs.

Page 6: Lymphatic Vessels

• Lymph Capillaries:

  • Similar to blood capillaries.

  • Features:

    • One-way flow.

    • More permeable to proteins.

    • Originate in interstitial spaces.

• Lymphatic Vessels:

  • Structure:

    • Similar to veins with three tunics.

    • Thinner walls and more valves than veins.

    • Examples of more anastomoses (connections).

Page 7: Functions of the Lymphatic System

• Removal of excess interstitial fluid.

• Filtering blood and lymph for microorganisms.

• Absorption and transportation of fats.

• Mechanism for immune response.

Page 8: Lymphatic Drainage

• Key Ducts:

  • Thoracic Duct: Main vessel for lymph drainage into blood.

  • Right Lymphatic Duct: Drains right upper body into the bloodstream.

• Regional Lymph Nodes:

  • Includes Inguinal, Axillary, and Cervical nodes.

Page 9: Lymph and Cardiovascular System Interaction

• Lymphatic capillaries origin from interstitial fluid.

• Tissue fluid circulates back to blood capillaries.

Page 10: Structure of Lymphatic Capillaries

• Anatomy:

  • Blind-ended tubes.

  • Adjacent endothelial cells form flaplike minivalves.

  • Anchored to connective tissue by filaments.

Page 11: Drainage Areas

• Duct Functions:

  • Right lymphatic duct drains right side:

    • Includes upper right limb.

  • Thoracic duct drains left side and lower body.

Page 12: Thoracic Duct Details

• Origin:

  • Starts at cisterna chyli, receiving lymph from digestive organs.

  • Posterior to the aorta; passes through aortic hiatus.

• Emptying:

  • Empties into left subclavian vein.

  • Right thoracic duct empties into right subclavian vein.

Page 13: Lymph Nodes

• Structure:

  • Oval/bean-shaped, enclosed in a capsule.

  • Contains afferent (incoming) and efferent (outgoing) lymphatic vessels.

  • Act as a biological filter.

• Large Collections:

  • Includes Inguinal, Axillary, and Cervical nodes.

Page 14: Lymph Node Structure

• Components:

  • Cortex:

    • Contains lymphatic follicles and germinal centers.

  • Medulla:

    • Contains medullary cords and sinuses.

  • Capsule and Trabeculae enclose the structure.

Page 15: Immune Cells in Lymph Nodes

• B Cells: Located in germinal centers of cortex.

• T Cells: Spread throughout the cortex.

• Macrophages: Found in subcapsular sinuses, assisting in filtering.

Page 16: Immune Response Overview

• Definition: Collection of defenses against pathogens, cancer cells, or foreign bodies.

• Types:

  • Innate Immunity: Nonspecific defenses.

  • Adaptive Immunity: Specific defenses, highly tailored to threats.

Page 17: Barriers in Innate Immunity

• Primary Barriers:

  • Skin and mucous membranes.

• Cells Involved:

  • Phagocytes: Neutrophils and Monocytes.

• Responses:

  • Inflammation and fever reactions to injury.

Page 18: Specific Immunity

• Characteristics:

  • Requires recognition mechanisms for pathogens.

  • Acquired through exposure to antigens.

• Key Cells:

  • T-Lymphocytes and B-Lymphocytes.

Page 19: Characteristics of Adaptive Immunity

• Memory: Provides future immunity (vaccines).

• Specificity: Targets specific antigens.

• Self-Tolerance: Ability to ignore body's unique surface proteins.

Page 20: T Cells & Cell-Mediated Immunity

• Development: Begin in bone marrow, mature in thymus, reside in lymph nodes.

• Types of Effector Cells:

  • Cytotoxic T cells, Helper T cells, Suppressor T cells.

Page 21: B Cells & Antibody-Mediated Immunity

• Function: Following rapid cell division:

  • Effector B cells become plasma cells.

  • Secrete antibodies to target free antigens.

• Circulation: Antibodies circulate in blood or lymph.

Page 22: Antibody Structure

• Components:

  • Antigen-binding site.

  • Variable and constant regions on heavy and light chains.

  • Disulfide bonds connect chains.

Page 23: Immunoglobulin Classes

• IgM: First antibody secreted in primary immune response; potent agglutination agent.

Page 24: Immunoglobulin Classes Continued

• IgA: Found in body secretions (saliva, sweat, milk); protects epithelial surfaces.

Page 25: Immunoglobulin Classes Continued

• IgD: Present on B cell surface; functions as an antigen receptor similar to IgM.

Page 26: Immunoglobulin Classes Continued

• IgG: Most abundant antibody; protects against bacteria, viruses, toxins; can cross the placenta.

Page 27: Immunoglobulin Classes Continued

• IgE: Associated with allergic reactions and parasitic invasions; stimulates histamine release.

Page 28: Spleen Anatomy

• Key Vessels:

  • Splenic artery and Splenic vein.

  • Contains a hilum for entry/exit of blood vessels.

Page 29: Spleen Structure

• Components:

  • Capsule, trabeculae, splenic cords, sinusoids, arterioles, and capillaries.

  • Distinction between red pulp and white pulp.

Page 30: Splenic Pulp

• White Pulp: Contains lymphocytes; involved in immune responses.

• Red Pulp: Contains macrophages; involved in RBC destruction.

Page 31: Functions of the Spleen

• Defense: Macrophages filter blood.

• Tissue Repair: Involves monocytes.

• Hematopoiesis: Produces lymphocytes and monocytes, especially during fetal development.

Page 32: Additional Functions of the Spleen

• Cell destruction: Destroys old RBCs and platelets.

• Serves as a blood reservoir, allowing self-transfusion when necessary.

Page 33: Overview of Tonsils

• Function: Masses of lymphoid tissue in the mouth & throat; first line of defense against bacteria.

• Types of Tonsils:

  • Palatine, pharyngeal, and lingual tonsils.

Page 34: Thymus Gland Overview

• Structure: An unpaired organ with two lobes located in the mediastinum, inferior to the thyroid.

• Components: Cortex and medulla with significant lymphocyte presence.

Page 35: Functions of the Thymus Gland

• Final site of prenatal lymphocyte development.

• Hormone production (thymosin) for maturation of T lymphocytes after birth.