Circulation of Lymph
Circulation of Lymph
The formation of lymphatics is like the veins and their walls are very thin. Like veins, there are many semilunar valves in the lymphatics on at the gaps of some distances. These valves are arranged in this way so that lymph keeps on flowing into one direction. There is no effective pump in the blood circulatory system for pushing lymph into the lymphatics but the lymph keeps on marching forwardly with the speed of circular and longitudinal smooth muscle situated in the walls of big lymphatics. Because of increasing the production of tissue fluid, the lymph reaches from one portion to another portion of the body because of the pressure produced because of the movement of respiration system’s muscles and other muscles of the body. The lymph does not return back because there are such valves in the lymphatics which open only in one direction.
All the lymph vessels reach towards the thoracic cavity. The right lymphatic duct circulates lymph contained by the head, face, right portion of the neck, right vertical arm, right chest and lung, right portion of the heart and lymphatics of upper portion of the liver into the subclavian vein.
The thoracic duct is bigger and thicker comparison to right lymphatic duct which starts under the diaphragm inside the abdomen in the dilated form which is called cisterna chili. From here, this duct reaches towards left side in the base of neck by passing through the hole of aorta of diaphragm upwardly in the mediastinum situated at the back side of the heart. Here it connects with the left jugular trunk which comes from the main part of the head and neck, left subclavian trunk which comes from the main part of left upper arm and chest and with other lymphatic vessels which come from the chest related parts. Finally, the thoracic duct opens into the left subclavian vein and circulates lymph into the blood.
In this way, lymphatic ducts keep on mixing lymph into the blood continuously by opening into the left and right subclavian veins.