M

LYMPHATIC SYSTEM

Lymph

Tissue fluid (interstitial fluid) that enters the lymphatic vessels

FORMATION AND TRANSPORT OF TISSUE FLUID

  • Essentially a drainage system accessory to venous system
  • Larger particles that escape into tissue fluid can only be removed via lymphatic system

Functions

  • Network that filters antigens from the interstitial fluid
  • Primary site of immune response from tissue antigens
  • Lymphatic drainage in all organs of the body except brain, eyes, marrow and cartilage
  • Flaccid thin walled channels → progressive caliber
  • 600 lymph nodes in body
  • Slow flow, low pressure system returns interstitial fluid to the blood system

Components of lymphatics

  • Lymph

  • Lymphatic Vessels

  • Lymphatic Organs

  • Lymphatic cells

    Lymphatic Capillaries

Features of structure:

  • Blind end

  • Single layer of overlapping endothelial cells

  • More permeable than that of blood capillary

  • Absent from avascular structures, brain, spinal cord splenic pulp and bone marrow

Lymphatic Vessels

  • Three layered wall but thinner than vein
  • More numerous valves than in vein
  • Interposed by lymph nodes at intervals
  • Arranged in superficial and deep sets

Lymph Trunks

  • Right and left jugular trunks
  • Right and left subclavian trunks
  • Right and left broncho mediastinal trunk
  • Right and left lumbar trunks
  • Intestinal trunk

Lymphatic Ducts

  • Right lymphatic duct

  • Thoracic duct

Lymphatic Cells

  • Also called lymphoid cells
  • Located in both the lymphatic system and the cardiovascular system.
  • Work together to elicit an immune response.

Types of lymphatic cells are:

  • Macrophages
  • Epithelial cells
  • Dendritic cells
  • Lymphocytes

Lymphatic Organs

  • Primary organs
    • Red bone marrow
    • Thymus gland
  • Secondary organs
    • Lymph nodes
    • Lymph nodules
    • Spleen

Lymph nodes:

  • Capsular shell

  • Fibroblasts and reticulin fibers

  • Macrophages

  • Dendritic cells

  • T cells

  • B cells

    Head & Neck Nodes

    Axillary Nodes

    Inguinal Lymph nodes

Lymphangitis

  • Inflammation of the lymph vessels

  • Commonest cause bacteria called streptococcus pyogenes(most common).

  • Lymph vessels appear as red streaks through the skin Lymphangitis

    FIlariasis

Lymphedema

  • Occurs due to accumulation of lymphatic fluid in the interstitial tissue

  • Sometimes can be appreciated after wearing tight clothing or jewelry on affected limb

    Lymphedema

Lymphadenopathy

  • Means a disease of the lymph nodes

  • Lymph nodes become swollen/ enlarged and may be painful to touch

    Lymphadenopathy

Lymphomas

  • Cancers originating either from the lymphocytes in the lymph nodes or the lymphatic tissue in organs

    Lymphomas

Tonsillitis

  • Infection of the pharyngeal tonsils

  • Tonsils are swollen, Fever and pain during swallowing usually present

    Tonsillitis