The lymphatic system (लसीका प्रणाली) is part of the vascular system and an important part of the immune system, composed of a large network of lymphatic vessels that carry a clear fluid called lymph directionally towards the heart. Unlike the circulatory system, the lymphatic system is not a closed system. The human circulatory system processes an average of 20 liters of blood per day. A lymphatic system, being one of the most important systems among humans, Siddha Spirituality of Swami Hardas Life System desires that our valuable readers read this article for wellbeing.
Lymphatic System Symptoms (लसीका प्रणाली के लक्षण)
- Swelling in hands, feet, and ankles but not limited to
- Water retention
- Muscle and joint stiffness especially when you first wake up
- Digestive disorders
- Skin conditions
- Sore throat
- Auto-immune disorders
- Sinus infections
Lymphatic system Structure (लसीका प्रणाली की संरचना)
The lymphatic system consists of lymphatic organs, a conducting network of lymphatic vessels, and the circulating lymph.
Primary or central lymphoid organs (प्राथमिक या केंद्रीय लसीकावत् अंग)
The thymus and the bone marrow constitute the primary lymphoid organs involved in the production and early clonal selection of lymphocyte tissues. Bone marrow is responsible for both the creation of T cells and the production and maturation of B cells. From the bone marrow, B cells immediately join the circulatory system and travel to secondary lymphoid organs in search of pathogens.
Secondary or peripheral lymphoid organs (माध्यमिक या परिधीय लसीकावत् अंग)
It includes lymph nodes and the spleen, maintains mature naive lymphocytes and initiates an adaptive immune response. The peripheral lymphoid organs are the sites of lymphocyte activation by antigens. Activation leads to clonal expansion and affinity maturation. Mature lymphocytes recirculate between the blood and the peripheral lymphoid organs until they encounter their specific antigen.
Secondary lymphoid tissue provides the environment for the foreign or altered native molecules to interact with the lymphocytes.
Gastrointestinal wall (जठरांत्र की दीवार)
In the gastrointestinal wall, the appendix has mucosa resembling that of the colon, but here it is heavily infiltrated with lymphocytes.
Tertiary lymphoid organs (तृतीयक लसीकावत् अंग)
These are abnormal lymph node-like structures that form in peripheral tissues at sites of chronic inflammation, such as chronic infection, transplanted organs undergoing graft rejection, some cancers, and autoimmune and autoimmune-related diseases.
Lymphoid tissue (लिम्फोइड ऊतक)
The thymus is a primary lymphoid organ and the site of maturation for T cells, the lymphocytes of the adaptive immune system. The thymus increases in size from birth in response to postnatal antigen stimulation, then to puberty and regresses thereafter.
The main functions of the spleen are to:
- Produce immune cells to fight antigens
- Remove particulate matter and aged blood cells, mainly red blood cells
- Produce blood cells during fetal life
The spleen synthesizes antibodies in its white pulp and removes antibody-coated bacteria and antibody-coated blood cells by way of blood and lymph node circulation.
Like the thymus, the spleen has only efferent lymphatic vessels. Both the short gastric arteries and the splenic artery supply it with blood.
Lymph nodes (लसीकापर्व)
A lymph node is an organized collection of lymphoid tissue, through which the lymph passes on its way back to the blood. Lymph nodes are located at intervals along with the lymphatic system. Several afferent lymph vessels bring in lymph, which percolates through the substance of the lymph node, and is then drained out by an efferent lymph vessel.
Other lymphoid tissue (अन्य लसीकावत् ऊतक)
Lymphoid tissue associated with the lymphatic system is concerned with immune functions in defending the body against infections and the spread of tumors. It consists of connective tissue formed of reticular fibers, with various types of leukocytes, mostly lymphocytes enmeshed in it, through which the lymph passes.
Regions of the lymphoid tissue that are densely packed with lymphocytes are known as lymphoid follicles. Lymphoid tissue can either be structurally well organized as lymph nodes or may consist of loosely organized lymphoid follicles known as the mucosa-associated lymphoid tissue.
Lymphatic vessels (लसीका वाहिका)
The lymphatic vessels, also called lymph vessels, conduct lymph between different parts of the body. They include the tubular vessels of the lymph capillaries, and the larger collecting vessels–the right lymphatic duct and the thoracic duct. The lymph capillaries are mainly responsible for the absorption of interstitial fluid from the tissues, while lymph vessels propel the absorbed fluid forward into the larger collecting ducts, where it ultimately returns to the bloodstream via one of the subclavian veins.
Lymphatic system Development (लसीका प्रणाली का विकास)
Tissues of the Lymphatic system begin to develop by the end of the fifth week of embryonic development. Lymphatic vessels develop from lymph sacs that arise from developing veins, which are derived from mesoderm.
The first lymph sacs to appear are the paired jugular lymph sacs at the junction of the internal jugular and subclavian veins. From the jugular lymph sacs, lymphatic capillary plexuses spread to the thorax, upper limbs, neck, and head. Some of the plexuses enlarge and form lymphatic vessels in their respective regions. Each jugular lymph sac retains at least one connection with its jugular vein, the left one developing into the superior portion of the thoracic duct.
The next lymph sac to appear is the unpaired retroperitoneal lymph sac at the root of the mesentery of the intestine. It develops from the primitive vena cava and mesonephric veins. Capillary plexuses and lymphatic vessels spread from the retroperitoneal lymph sac to the abdominal viscera and diaphragm. The sac establishes connections with the cisterna chyli but loses its connections with neighboring veins.
Last, of the lymph sacs, the paired posterior lymph sacs, develop from the iliac veins. The posterior lymph sacs produce capillary plexuses and lymphatic vessels of the abdominal wall, pelvic region, and lower limbs. The posterior lymph sacs join the cisterna chyli and lose their connections with adjacent veins.
Lymphatic system Function (लसीका प्रणाली का कार्य)
The lymphatic system has multiple interrelated functions:
- It is responsible for the removal of interstitial fluid from tissues
- It absorbs and transports fatty acids and fats as chyle from the digestive system
- It transports white blood cells to and from the lymph nodes into the bones
Fat absorption (वसा का अवशोषण)
Lymph vessels called lacteals are at the beginning of the gastrointestinal tract, predominantly in the small intestine.
Immune function (प्रतिरक्षा कार्य)
The lymphatic system plays a major role in the body’s immune system, as the primary site for cells relating to the adaptive immune systems including T-cells and B-cells. Cells in the lymphatic system react to antigens presented or found by the cells directly or by other dendritic cells. When an antigen is recognized, an immunological cascade begins involving the activation and recruitment of more and more cells, the production of antibodies and cytokines and the recruitment of other immunological cells such as macrophages.
Lymphatic system Clinical significance (लसीका प्रणाली का नैदानिक महत्व)
Because of its closeness to many tissues of the body, lymphatic system is responsible for carrying cancerous cells between the various parts of the body in a process called metastasis. The intervening lymph nodes can trap the cancer cells. If they are not successful in destroying the cancer cells the nodes may become sites of secondary tumors.
Enlarged lymph nodes (बढ़े हुए लिम्फ नोड्स)
Lymphadenopathy refers to one or more enlarged lymph nodes. Small groups or individually enlarged lymph nodes are generally reactive in response to infection or inflammation. This is called local lymphadenopathy.
Lymphedema is the swelling caused by the accumulation of lymph, which may occur if the lymphatic system is damaged or has malformations. It usually affects limbs, though the face, neck, and abdomen may also be affected. In an extreme state, called elephantiasis, the edema progresses to the extent that the skin becomes thick with an appearance similar to the skin on elephant limbs.
Causes are unknown in most cases, but sometimes there is a previous history of severe infection, usually caused by a parasitic disease, such as lymphatic filariasis.
Lymphangiomatosis is a disease involving multiple cysts or lesions formed from lymphatic vessels.
Lymphedema can also occur after surgical removal of lymph nodes in the armpit (causing the arm to swell due to poor lymphatic drainage) or groin (causing swelling of the leg).
There is no evidence to suggest that the effects of manual lymphatic drainage are permanent.
Lymphatic system Cancer (लसीका प्रणाली कैंसर)
Cancer of the lymphatic system can be primary or secondary. Lymphoma refers to cancer that arises from lymphatic tissue. They are called “leukemia” when in the blood or marrow and “lymphoma” when in lymphatic tissue.
Chemotherapy generally involves the ABVD and may also involve radiotherapy. Non-Hodgkin lymphoma is cancer characterized by increased proliferation of B-cells or T-cells, generally occurs in an older age group than Hodgkin lymphoma. It is treated according to whether it is high-grade or low-grade and carries a poorer prognosis than Hodgkin lymphoma.
Lymphangiosarcoma is a malignant soft tissue tumor, whereas lymphangioma is a benign tumor occurring frequently in association with Turner syndrome. Lymphangioleiomyomatosis is a benign tumor of the smooth muscles of the lymphatics that occurs in the lungs.
Lymphoid leukemia is another form of cancer where the host is devoid of different lymphatic cells.
Other clinical significances (अन्य नैदानिक महत्व)
- Castleman’s disease
- Kawasaki disease
- Kikuchi disease
- Lymphocytic choriomeningitis
- Solitary lymphatic nodule
- Lymphatic filariasis