LYMPHATIC SYSTEM

The lymphatic system is a network of tissues and organs that help rid the body of toxins, waste and other unwanted materials. The primary function of the lymphatic system is to transport lymph, a fluid containing infection-fighting white blood cells, throughout the body. The lymphatic system primarily consists of lymphatic vessels, which are similar to the circulatory system's veins and capillaries. The vessels are connected to lymph nodes, where the lymph is filtered. The tonsils, adenoids, spleen and thymus are all part of the lymphatic system.

The lymphatic system

There are thousands of lymph nodes in the human body. They are located deep inside the body, such as around the lungs and heart, or closer to the surface, such as under the arm or groin.The spleen, which is located on the left side of the body just above the kidney, is the largest lymphatic organ. It controls the amount of red blood cells and blood storage in the body, and helps to fight infection. If the spleen detects potentially dangerous bacteria, viruses, or other microorganisms in the blood, it along with the lymph nodes creates white blood cells called lymphocytes, which act as defenders against invaders. The lymphocytes produce antibodies to kill the foreign microorganisms and stop infections from spreading. Humans can live without a spleen, although people who have lost their spleen to disease or injury are more prone to infections.
The thymus is located in the chest just above the heart. This small organ stores immature lymphocytes (specialized white blood cells) which help destroy infected or cancerous cells.

Tonsils are large clusters of lymphatic cells found in the pharynx. they are the body's "first line of defense as part of the immune system. They sample bacteria and viruses that enter the body through the mouth or nose." They sometimes become infected, and although tonsillectomies occur much less frequently today, it is still among the most common operations performed and typically follows frequent throat infections.

Lymph is a clear and colorless fluid; the word "lymph" comes from the Latin word lympha, which means connected to water.
Plasma leaves the body's cells once it has delivered its nutrients and removed debris. Most of this fluid returns to the venous circulation through tiny blood vessels called venules and continues as venous blood. The remainder becomes lymph.
Unlike blood, which flows throughout the body in a continue loop, lymph flows in only one direction upward toward the neck. Lymphatic vessels connect to two subclavian veins, which are located on either sides of the neck near the collarbones, and the fluid re-enters the circulatory system.