The lymphatic system consists of tissues and organs that are specialized in producing, storing and carrying WBCs that are fighters of the body against infection and other diseases. Spleen, thymus, bone marrow, lymph nodes and lymphatic vessels are included in this system. Lymphatic vessels branch into all the tissues of the body and function in a similar way to blood vessels.
The lymph (fluid which runs in the lymph vessels) travels around the body in a network of vessels similar to the blood which travels around the body in the blood vessels. Lymph drains fluid from the tissue and transports it to the lymph nodes as compared to the blood which carries oxygen, nutrients and other substances into our tissue.
Lymph nodes clean the lymph from bacteria or any other harmful substance, then this cleaned lymph is carried back to the vein named as superior vena cava through which it enters the bloodstream. The lymphatic system plays an important function in defending our body against the infection1.
So, the extra-cellular space which carries the extra-cellular fluid and extracellular cells which are collectively known as lymph is drained through lymphatic vessels to the superior vena cava and during this travel, the lymph passes through lymph nodes which clean it from bacteria and other harmful substances2.
Some of the basic vital functions of the lymphatic system are as follows:
1. Regulation of the tissue pressure
2. Immune surveillance
3. Absorption of the dietary fat in the intestine3
Lymph vessels have overlapping junctions in them. These junctions contain primary valves in them which allows the lymph vessels to make the lymph drainage unidirectional4.
Lacteals are the lymphatic vessels in the intestine that absorb and transport fats lipids and large molecules in the intestine. These molecules are mainly absorbed in the form of lipoproteins such as chylomicron which are created by enterocytes of the intestine and consist of phospholipids, cholesterol, proteins and triglycerides5.
Many malignant tumors use the lymphatic system for their dissemination6.
The lymphatic system plays an important role in maintaining body homeostasis. Its main components are:
1. Macrophages, Lymphocytes, Dendritic Cells which can be named as fighter cells.
2. Thymus, spleen, Lymph node, Bone marrow which can be named as Fighter Tissues.
3. Lymphatic Vessels
4. Fluid (Lymph)
These organs collectively play an important role in maintaining the internal environment of the body7.