Lymphatic System Dr. Sama-ul-Haque Dr. Sama-ul-Haque

Objectives Define Lymphatics and its distribution in body. Define Lymphatics and its distribution in body. Explain the anatomical structure and components of the lymphatic system including the lymphatic circulation. Explain the anatomical structure and components of the lymphatic system including the lymphatic circulation. Enumerate functions of lymphatic system. Enumerate functions of lymphatic system. How a lymphatic vessel forms. How a lymphatic vessel forms.

The Lymphatic System The lymphatic system is a specialized component of the circulatory system that monitor body surfaces and internal fluid compartment and reacts against potentially harmful substances. The lymphatic system is a specialized component of the circulatory system that monitor body surfaces and internal fluid compartment and reacts against potentially harmful substances. It consists of: It consists of: Lymph. Lymph. Lymphatic vessels. Lymphatic vessels. Lymphatic cells. Lymphatic cells. Lymphatic nodules. Lymphatic nodules. Lymphoid organs. Lymphoid organs.

Functions Remove excess fluids from body tissues & transport of tissue fluid back into the blood circulation. Absorb & remove large Protein molecules. Absorb fatty acid and transport fat to circulatory system from intestinal villi. Produce immune cells. (lymphocytes, monocytes & plasma cells).

Lymph Interstitial fluid: Fluid that fills the spaces around cells. Lymph Clear, watery fluid found in the lymphatic vessels. Clear, watery fluid found in the lymphatic vessels. Plasma filters into the interstitial spaces from blood flowing through the capillaries. Plasma filters into the interstitial spaces from blood flowing through the capillaries. Much of this interstitial fluid is absorbed by tissue cells or reabsorbed by the blood, small amount of interstitial fluid is left behind. Much of this interstitial fluid is absorbed by tissue cells or reabsorbed by the blood, small amount of interstitial fluid is left behind. It is twice as blood in our body. It is twice as blood in our body.

Origin of a lumphatic vessel

Lymphatic Vessels Lymphatic vessels drain interstitial fluid (cells and large macromolecules) from tissues to venous blood. Lymphatic vessels drain interstitial fluid (cells and large macromolecules) from tissues to venous blood. Lymphatic vessels are found in most of tissues and organs in the body but absent from: Lymphatic vessels are found in most of tissues and organs in the body but absent from: CNS. CNS. Eye ball. Eye ball. Internal ear. Internal ear. Epidermis. Epidermis. Cartilage. Cartilage. Bone. Bone.

Structure of lymphatics The lymphatics resemble veins in structure with these exceptions: The lymphatics resemble veins in structure with these exceptions: Lymphatics have thinner walls. Lymphatics have thinner walls. Lymphatics contain more valves. Lymphatics contain more valves. Lymphatics contain lymph nodes located at certain intervals along their course. Lymphatics contain lymph nodes located at certain intervals along their course.

Lymphatic circulation Blind ended lymphatic capillaries. Blind ended lymphatic capillaries. Afferent lymphatics. Afferent lymphatics. Lymph nodes. Lymph nodes. Efferent lymphatics. Efferent lymphatics. Thoracic duct/ Right lymph duct. Thoracic duct/ Right lymph duct. Blood circulation. Blood circulation.

Main Lymphatic Channels (Thoracic duct & Right lymph duct)

Cells of the Lymphatic System Lymphocytes are the chief cells of lymphatic system with supporting cells. About 70% of lymphocytes circulate in blood and lymphatic circulation. About 30% of lymphocytes do not enter in lymphatic system and pass directly to sub-epithelial tissues for surveillance.

Lymphatic organs Primary lymphatic organs Organs where lymphocytes become initially immunocompitant e.g. bone marrow and thymus. Secondary lymphatic organs Organs where immunocompitant lymphocytes form effector lymphatic tissue and organs e.g. lymphatic nodules, lymph nodes, tonsils and spleen.

Lymph is driven by contraction of surrounding muscles, aided by valves enabling one-way flow.

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