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Lymphatic System: Facts, Functions and Diseases

  • Posted on- Oct 23, 2015
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The lymphatic system is one of the important parts of the human immune system. This system forms a network throughout the body. The capillaries or tubes which form this network are known as lymphatics vessels. Being a part of the immune system, the lymphatic system fights off infections.

Facts about the Lymphatic System

The lymphoid tissues which carry lymph are important constituents of the lymphatic system. Lymphocytes are the white blood cells of the lymphatic system. The lymphocytes along with other white blood cells form the lymph tissues. Lymphocytes are classified into 2 types, i.e. B-lymphocytes (B-cells) and T-lymphocytes (T-cells). The T-cells are known to fight off the infection of viruses. Cells infested by viruses and few other microbes are destroyed by T-cells. B-cells take care of pathogenic bacteria. The T-cells are further classified into helper T-cells and killer T-cells. The helper T-cells inform killer T-cells about an infection by producing lymphokines. This acts as a trigger for the killer T-cells to multiply and then attack the pathogens. The network or conducting system is composed of the lymph vessels, lymph capillaries, and thoracic ducts (left and right). The lymphatic system organs such as the spleen, tonsils, thymus and adenoids, are explained below.

  • Thymus: The thymus is situated as the basal region of heart. This organ is made up of lymphatic tissues and has a bilobed structure. Thymus takes part in the development of the immune system.
  • Tonsils: This organ of the lymphatic system is located near the nasopharynx and oropharynx. Just like the thymus, the tonsils too are involved in protecting the body against infection.
  • Adenoids: The adenoids can be described as a mass of lymphoid tissue that is situated at the top of the nasopharynx. The pseudostratified columnar ciliated epithelium differentiates adenoids from other tonsils.

Functions of the Lymphatic System

The main function of the lymphatic system is to remove interstitial fluids out of the lymphoid tissues in our body. However, it performs many other functions other than just removing interstitial fluids from the lymphoid tissues. The transportation of lymphocytes from bone marrow to the lymph nodes is also one of its main functions. The lymphatic system absorbs fats and fatty acids from the circulatory system. These fats are absorbed in the form of a substance called chyle.

Diseases of the Lymphatic System

The lymphatic system is affected by diseases like lymphedema, Lymphangiosarcoma, elephantiasis, Hodgkin's lymphomanon-Hodgkin's lymphoma, etc.

In lymphedema, the lymph fluid is retained in the lymphoid tissues instead of being thrown out. The fluid retention causes swelling of this gland. The risk of this gland getting infected also increases due to swelling. Limbs become swollen and the patient experiences fatigue. The fluid is accumulated mainly in head and neck region. Skin overlying this swelling becomes discoloured. In this condition, development of a malignant tumour takes place. The tumour first appears like a bruise mark and slowly turns purplish. This disease is treated with chemotherapy and surgery.

Lymphatic System Facts for Children

Some other interesting facts about the lymphatic system are given below:
  • It is interesting to know that bone marrow plays an important role in the functioning of lymphatic system. Production of lymphocytes (immune system) takes place in the bone marrow. This is why the destruction of bone marrow affects our immunity.
  • The small organs which compose lymphatic system are known as lymph nodes. The number of lymph nodes present in our body range from 500 - 700.
  • The different organs of our body, like the groin, underarms and neck, possess these nodes in large numbers.
  • The circulatory system functions with the help of pressure emitted by heartbeats. The lymphatic system doesn't possess any such organ (like heart) which can help in movement of fluids through its network. Pressure created by muscle movement and heartbeats is therefore used by the lymphatic system to carry out its functions smoothly.
  • In case the body is affected by germs, the lymph nodes start swelling. The swelling of lymph nodes takes place because germs, if any, in the body, are absorbed by them (nodes) and white blood cells are use to fight them (germs) off.
  • The B-cells (lymphocytes) are known to fight off pathogenic bacteria. However, a special type of B-cells known as memory B-cells protects the body from attack by similar pathogens in the future.