Lymphatic System Review

Lymphatic System Checklist Models

  • Key Components of the Lymphatic System

    • Splenic artery and splenic vein

    • Lymphatic vessels

    • Subclavian vein and internal jugular vein junction (duct drainage)

    • Lymph Nodes:

    • Cervical

    • Axillary

    • Inguinal

    • Common iliac

    • Spleen

    • Thoracic duct

    • Right lymphatic duct

    • Cisterna chyli

    • Pharyngeal tonsil

    • Palatine tonsils

    • Lingual tonsils

  • Images (from book, PowerPoint, lab manual)

    • Thymus

    • Red bone marrow

Histology of Lymphatic Components

  • Lymphatic Vessel (10X Magnification):

    • Structure featuring valves

  • Peyer's Patch (4X Magnification):

    • Specialized lymphoid tissue in the intestine

  • Thymus (4X Magnification):

    • Cortex: Contains densely packed lymphocytes.

    • Medulla: Contains fewer lymphocytes and Hassall's corpuscles organized in lobules.

  • Lymph Node (4X Magnification):

    • Capsule: Outer protective layer.

    • Cortex: Contains lymphatic nodules and follicles; involved in B-cell proliferation.

    • Medulla: Contains medullary cords rich in lymphocytes and plasma cells.

    • Germinal Centers: Sites within lymph nodes where B cells proliferate and differentiate.

  • Spleen - Mammal (4X/10X Magnification):

    • Capsule: Protective outer layer.

    • Red Pulp: Contains red blood cells, sinuses, and macrophages; involved in filtering blood.

    • White Pulp: Contains lymphatic tissue and is associated with immune functions.

Functions of the Lymphatic System

  • Primary Lymphatic Structures:

    • Thymus

    • Red bone marrow

  • Secondary Lymphatic Structures:

    • Spleen

    • Lymph nodes

    • Tonsils (pharyngeal, palatine, lingual)

    • MALT (mucosa-associated lymphoid tissue), specifically Peyer’s patches

  • Lacteal: Specialized lymphatic vessels in the intestine that absorb dietary fats.

  • Duct Drainage:

    • Thoracic Duct: Drains lymph from the entire body except the right upper quadrant; drains into the left subclavian vein.

    • Right Lymphatic Duct: Drains lymph from the right upper quadrant of the body; drains into the right subclavian vein.

    • Cisterna Chyli: The dilated sac that collects lymph from the lower body before entering the thoracic duct.

Additional Information

  • Path of Lymph: Lymph travels through the lymphatic vessels and drains into the venous circulation at the subclavian veins.

  • Difference Between Primary and Secondary Lymphatic Organs:

    • Primary lymphatic organs (e.g., thymus, red bone marrow) are involved in the production and maturation of immune cells.

    • Secondary lymphatic organs (e.g., lymph nodes, spleen) are involved in the activation and proliferation of lymphocytes.

Clinical Observations and Age-Related Changes

  • Age-related Changes in Thymus:

    • The thymus decreases in size and function with age, resulting in a decrease in T-cell production.

  • Swollen Glands:

    • Refers to the enlargement of lymph nodes, often indicating an immune response to infection or inflammation.

  • Germinal Centers:

    • Sites of B-cell maturation and proliferation in the lymph nodes, which also contain helper T-cells and follicular dendritic cells.

  • Red Pulp Composition:

    • Contains blood and macrophages that assist in filtering debris and dying red blood cells.

  • White Pulp Composition:

    • Associated with immune function; contains lymphocytes that respond to blood-borne antigens.

  • Alternative Name for Pharyngeal Tonsil:

    • Also known as adenoids.

  • Symptoms of Inflamed Tonsils:

    • Common symptoms include sore throat, difficulty swallowing, and swollen lymphoid tissue.