Lymphatic System of the Body

Lymphatic System of the Body

A network of organs, nodes, ducts, vessels that which is a major part of the body’s immune system and also the drainage system of the body that helps the body get rid of excess fluid and waste products is called the lymphatic system. It consists of the following:

  1. Organs
    1. Spleen monitors the composition of blood components, the location of pathogen engulfment and eradication, the immunologic response, and the regulation site. Spleen is the largest lymphatic organ, is a convex lymphoid structure located below the diaphragm and behind the stomach.
    2. Thymus serves as the site of T-lymphocyte maturation, development, and control.
    3. Tonsils are aggregates of lymph node tissue located under the epithelial lining of the oral and pharyngeal areas. The main areas are the palatine tonsils (on the sides of the oropharynx), the pharyngeal tonsils (on the roof of the nasopharynx; also known as adenoids), and the lingual tonsils (on the base of the posterior surface of the tongue).
    4. Adenoidsare a mass of soft tissue behind the nasal cavity.White blood cells circulate through the adenoids and other lymphoid tissue, reacting to foreign invaders in the body.


  1. Lymph:
    1. Lymph is a fluid derived from the blood plasma, a clear-to-white fluid made of white blood cells, especially lymphocytes, the cells that attack bacteria in the blood; fluid from the intestines called chyle, which contains proteins and fats.
    2. It contains nutrients, oxygen, hormones, and fatty acids, as well as toxins and cellular waste products that are transported to and from cellular tissues.


  1. Lymph nodes:
    1. They are soft, small, round- or bean-shaped structures, usually cannot be seen or easily felt. Lymph nodes are located in clusters in various parts of the body, such as neck, armpit, groin, inside the center of chest and mesenteries of the gastrointestinal tract.
    2. Monitor the composition of lymph, the location of pathogen engulfment and eradication, the immunologic response, and the regulation site.
    3. They are widely distributed throughout the lymphatic pathway, providing a filtration mechanism for the lymph before it rejoins the blood stream.
    4. The average human body contains approximately 600-700 of them.
    5. Lymph nodes constitute a main line of defense by hosting 2 types of immunoprotective cell lines, T lymphocytes and B lymphocytes.


  1. Lymph duct
    1. It is a great lymphatic vessel that empties lymph into one of the subclavian veins.
    2. There are two lymph ducts in the body—the right lymphatic duct and the left thoracic duct. The right lymphatic duct drains lymph from the right upper limb, right side of thorax and right halves of head and neck.


  1. Lymph vessels:
    1. Transport lymph from peripheral tissues to the veins of the cardiovascular system.
    2. Lymphatic capillaries are blind-ended tubes with thin endothelial walls (only a single cell in thickness). They are arranged in an overlapping pattern, so that pressure from the surrounding capillary forces at these cells allows fluid to enter the capillary.
    3. The lymphatic capillaries merge to form a larger meshlike network of tubes that are located deeper in the body; these are known as lymphatic vessels.


The lymphatic system is uniqueone-way system that returns lymph fluid via vessels to the cardiovascular system for eventual elimination of toxic byproducts by end organs, such as the kidney, liver, colon, skin, and lungs. Thus, the lymphatic system’s main functions are as follows:

  • Restoration of excess interstitial fluid and proteins to the blood
  • Absorption of fats and fat-soluble vitamins from the digestive system and transport of these elements to the venous circulation
  • Defense against invading organisms


Diseases of the lymphatic system include lymphedema, lymphoma, lymphadenopathy, lymphadenitis, filariasis, splenomegaly, and tonsillitis.

  • Lymphedema results when the lymphatic system cannot adequately drain lymph, resulting in an accumulation of fluid that causes swelling.
  • Lymphoma is a medical term used for a group of cancers that originate in the lymphatic system.
  • Lymphadenopathy is a lymphatic disorder in which the lymph nodes become swollen or enlarged as a consequence of an infection. For example, swollen lymph nodes in the neck may occur as a result of a throat infection or sinus infection.
  • Lymphadenitis is an inflammation of the lymph node that is due to a bacterial infection of the tissue in the node, which causes swelling, reddening, and tenderness of the skin overlying the lymph node.
  • Filariasis is a lymphatic system disorder that results from a parasitic infection that causes lymphatic insufficiency.
  • Splenomegaly, or enlarged spleen, is a lymphatic system disorder that develops as a result of a viral infection, such as mononucleosis.
  • Tonsillitis is caused by an infection of the tonsils (the lymphoid tissues present in the back of the oral cavity).
  • Adenoiditis is the inflammation of the adenoids, often caused due to bacterial or viral


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