The description of the lymphatic system was first provided by Thomas Bartholin and Olaus Rudbeck. As a part of the immune system, the lymphatic system performs the work of circulating immune cells called 'lymphocytes'. These cells protect the body from harmful microorganisms.
Another major function of this system is to maintain normal pressure and volume of blood by draining excess lymph (a clear liquid in the body) surrounding the tissues and organs, and returning it to the bloodstream. It also prevents a condition called edema, which is the excess accumulation of fluid around tissues.
The lymph node is present at different locations in the body. This organ is important for smooth functioning of the immune system. The lymph nodes are formed of lymphatic tissues, which are enclosed in a fibrous capsule.
Filtration of lymph is the main function of these nodes which involves separation of phagocytes, microorganisms, and damaged cells. Production of lymphocytes, antitoxins, and antibodies also is an important function of the lymph nodes. These nodes are found in the head, neck, thorax, arms, and lower limbs.
The number of lymph nodes present in our body ranges between 500 and 600. The nodes present in the head and neck region are cervical, tonsillar, sub-mandibular, and retropharyngeal lymph nodes. The cervical nodes are two in number i.e., anterior and posterior cervical.
Sub-mental and supraclavicular are the two retropharyngeal lymph nodes. The lymph nodes of the lungs are subsegmental, lobar, segmental, and interlobar. The lymph node of the thoracic region is mediastinal lymph node.
Supratrochlear and deltopectoral are superficial lymph nodes of the arm. Lateral, pectoral, intermediate, subscapular, and subclavicular are the deep lymph glands of the arm. Superficial inguinal, popliteal, and deep inguinal lymph nodes are located in the lower limbs.
This organ is located at the front part of the abdominal vertebrae (upper). It receives the lymph from the abdominal cavity, pelvic cavity, and legs. A duct called the thoracic duct emerges from cysternae chyli.
It carries out the function of transporting lymph from left side of the body. This duct carries lymph through subclavian vein. Lymph from right side of the body is carried by right lymphatic duct through right subclavian vein.
The structure of thymus is characterized by two lobes, which have an identical appearance. This organ carries out the production and secretion of thymosins. T-lymphocytes, the important cells of adaptive immune system are controlled by the thymosins.
The central region of thymus is the medulla, while the cortex is present at the periphery. The whole structure is surrounded by a capsule. The development process of T-lymphocyte cells is supported by the thymus.
The spleen is a secondary lymphoid organ. It is located in the abdominal cavity, just behind the stomach and to the left side of the body. A collagenous capsule encloses the sac-like structure called spleen, which is normally purple/red in color. The spleen turns pink when it is in the process of fighting off infection.
The collagenous extensions known as trabeculae are present in the spleen and form a part of the support structure of this organ. A network of reticular fibers originate from the trabeculae. This network appears more like the plant-root system. The reticular cells are present on top of the reticular fibers.
Thus, the lymphatic system, which protects the body from pathogens is divided into various organs, and these organs are important from the point of immune system functioning.
Disclaimer: This is for informative purposes only, and should not be used as a replacement for expert medical advice.