Why Lymphatic Drainage Works?
The lymphatic system is a major component of the immune system.
The lymphatic system has three interrelated functions:
(1) removal of excess fluids from body tissues,
(2) absorption of fatty acids and subsequent transport of fat, as Chyle (Chyle is a milky fluid (bodily fluid) consisting of lymph and emulsified fats, or free fatty acids (FFAs). It is formed in the small intestine during digestion of ingested fatty foods and taken up by lymph vessels specifically known as lacteals, unlike other components of digested food that are conveyed by veins. The lacteals are much better suited for the transport of FFAs away from the gastrointestinal tract).
(3) production of immune cells (such as lymphocytes, monocytes, and antibody producing cells called plasma cells).
Lymph originates as blood plasma that leaks from the capillaries of the circulatory system, becoming interstitial fluid, and filling the space between individual cells of tissue. Plasma is forced out of the capillaries (called filtration) and forced back in (called absorption) due to interactions of hydrostatic pressure (favoring movement out of the capillaries) and oncotic pressure (favoring movement into the capillaries). While out of the capillaries, the fluid mixes with the interstitial fluid, causing a gradual increase in the volume of fluid. Most of the fluid is returned to the capillaries. The proportion of interstitial fluid that is returned to the circulatory system by osmosis is about 90% of the former plasma, with about 10% accumulating as overfill. The excess interstitial fluid is collected by the lymphatic system by diffusion into lymph capillaries, and is processed by lymph nodes prior to being returned to the circulatory system. Once within the lymphatic system the fluid is called lymph, and has almost the same composition as the original interstitial fluid.
Lymphatic Circulation Unlike the blood system, the lymphatic system is not closed and has no central pump. Lymph movement occurs slowly with low pressure due to peristalsis, valves, and the milking action of skeletal muscles. Like veins, lymph travels through vessels in one way only, due to semilunar valves. This depends mainly on the movement of skeletal muscles to squeeze fluid through them, especially near the joints. Rhythmic contraction of the vessel walls through movements may also help draw fluid into the smallest lymphatic vessels, capillaries. Tight clothing can restrict this, thus reducing the removal of wastes and allowing them to accumulate. If tissue fluid builds up the tissue will swell; this is called oedema. As the circular path through the body’s system continues, the fluid is then transported to progressively larger lymphatic vessels culminating in the right lymphatic duct (for lymph from the right upper body) and the thoracic duct (for the rest of the body); both ducts drain into the circulatory system at the right and left subclavian veins. The system collaborates with white blood cells in lymph nodes to protect the body from being infected by cancer cells, fungi, viruses or bacteria. This is known as a secondary circulatory system.
