Figure shows a typical lymph node. The plasma cells mentioned in the above figure are the large antibody providing cells that develop into B cells. The antibodies play a vital role in the immune system. The outgoing Lymph vessel carries the immune cells as well as the debris of the invaders.
It is obvious that the lymphatic system plays a vital role in body’s immune system. We shall now discuss this.
Overview of Lymphatic System
It is important to note that:
- Lymphatic system is primary component of the body’s immune system.
- It carries fluids infused with bacteria, virus, and fungus into immune-active lymph nodes.
- At the nodes, lymphocytes, reticular cells and macrophages kill or neutralize toxic, enemy cells and organisms.
- Lymphatic system collects interstitial fluid with the byproducts of cellular activity and transports it to blood system.
- Lymphatic system assists in bringing nutritional factors in proximity with tissues.
- Breath, movement and postures have profound influence on lymphatic especially in production and circulation of lymph.
- Lymph fluid is partly cellular water and part blood plasma
Several mechanisms are associated with lymphatic system. They are;
- Lymph generation
- Lymph propulsion
- Immune system
- Cerebrospinal fluid circulation
- Nutritive mechanism
We shall now discuss the most important aspects of lymph generation, propulsion.
Mechanism of Lymph Generation
As late as 1985, medical science believed that generation of lymph is due to filtration of blood plasma from capillaries. This view has now altered.
It is now understood that the major portion of the body’s lymph is produced by the identical physiological process that generates body’s chemical energy (oxygen metabolism).in the simplest form, at the cell level following chemical reaction takes place
6O2 (from breath) + C6H12O6 (glucose in blood) + BMR (basal metabolic rate) = ergs (energy) +6Co2 +6H2O (pure water)
Thus six molecules of water are generated for each six molecules of oxygen that are metabolized in energy production. This water and the blood plasma make the lymph fluid. As per calculations of Krebs cycle, about 700 -1000 cc of pure interstitial water is produced in a semi active person. In an active person practicing Pranayama, yogasanas etc, this amount goes up to 1400 cc and is put in subclavian vein daily. It should be remembered that in the above reaction, the oxygen uptake by the blood is very important as we discussed in our earlier paper. This uptake depends upon the hemoglobin content of the blood.
This water is the vehicle of transport for metabolic byproducts into lymph vessel. From the tissues it is propelled as lymph to the immune potent nodal treatment sites and finally to the elimination organs via the blood.
Part of the constituents of blood goes out of blood capillaries to join surrounding tissues passing through the space between each cell.
The liquid that is filtered from the blood capillary is reabsorbed: 1) 80 -98 % by the small veins emerging from blood capillaries and remaining 2 -20% by the small initial lymphatic capillaries. In case the body is unable to use the remaining liquid, the fluid gets accumulated. The result is swelling in that particular tissue. This could, in long run, cause severe complications.
The lymphatic system should therefore fine tune the drainage of the space between the cells. This drainage is very important as it evacuates water and excess substances in the interstitial environment.
Some of the Kriyas such as Svedan in Panchakarma (detoxification procedures in Ayurvedic medical system) aim at creating a perfect balance of the overflow and thus toxins are driven out of the body.
Initial lymph capillaries which originate in almost every tissue are at their beginning feather fine. They slowly increase in size moving into lymphatic collectors and eventually join major venous circulation, just before reaching the heart, behind clavicles. Thus lymph circulation ends in systemic blood circulation just before heart. Prior to that, the lymphatic system transports proteins, foreign bodies and pathogenic agents (toxins, germs etc) in its pathway through lymphatic nodes which act as purification centers. The nodes destroy these particles so that eventually they can be flushed out of the body through alimentary tract.
Mechanism of Lymph Propulsion
The human blood circulation system uses heart as the pumping mechanism. There is however, no pumping organ for the circulation of the lymph. The lymphatic flow can stagnate or even stop for many reasons such as fatigue, stress, emotional shock, consumption of certain foods. This, of course does not cause instant death as it may happen when heart fails to work. But then it creates such bad health conditions that the quality of life becomes extremely poor. This is because supplying and regeneration of cells is very poorly carried out. The toxins accumulate, aging hastens and flood gates are open for proliferation of very complex health disorders.
How to ensure proper lymph movement
The following enable propulsion of the lymph.
- Breathing mechanism.
- Specific body postures called yogasanas.
- Yogic exercise “Surya Namaskar” is one of most effective way for lymph propulsion.
- Walking/jogging and other aerobic exercises.
The oxygen metabolism reaction produces pure water which is the raw material for the production of lymph. The interstitial water is collected through feather like capillaries and during the course, blood plasma, the lymphocytes, nutrients and the cerebrospinal fluid containing the Neuropeptides get added to make the lymph. Ultimately the lymph enters the blood circulation system at right and left subclavian vein.The body’s biggest lymphatic vessel is the thoracic duct. Itbegins near the lower part of the spine. Thoracic duct collects lymph from the lower limbs, pelvis, abdomen and lower chest..
Lymph and Pranayama
The rate of flow of the lymph at the thoracic duct is proportional to the depth of inhalation. The total volume of lymph that enters the central veins depends both on the depth of inhalation and the overall breathing rate. The diaphragm is the main pump of the lymphatic system.
It is for this reason that Yoga practice strongly recommends many of the Asana and especially Surya Namaskar which greatly tone up diaphragm and also increase the flow of lymph. Thus the most powerful apparatus for lymph propulsion is the breath apparatus. The lymphoid tissue is concentrated just above and below the diaphragm. Lymph that has been carried from all over the body accumulates centrally and is then propelled by breath/diaphragm in a final rush through thoracic lymph duct into the blood at subclavian vein where it leaves its identity as lymph and is transformed into blood serum. Above the diaphragm, the thoracic duct of the lymphatic system is a central large size collecting vessel. Below the diaphragm a substantial dilation of thoracic duct forms a collecting capsule that is called “Cisterna Chyli reservoir” which contains chyle (milky fluid containing nutrients, lacteals absorbed from small intestine) and lymph that carries metabolic by products of tissues, muscles and glands.
How proper breathing ensures effective lymph generation and propulsion
The circulation of lymph is most optimum when we do deep breathing involving the diaphragm. It is important to note the following points:
- During Pranayama inhalation, the diaphragm goes down and the lymph is forced upwards into subclavian vein.
- During Pranayama exhalation the lymph reservoir fills up.
- Same phenomena occur during aerobic exercises but aerobic exercises are energy spending (catabolic) processes.
- Bhastrika, Kapalbhati and Anulom – Vilom are the most effective Pranayama breathing methods that build up body’s immune system through optimum circulation of lymph.