Definition and Function of Lymph The lymph circulatory system has a close relationship with the blood circulatory system so that both are important in the transportation system in the human body. The lymph is clear yellowish in colo. This fluid is caused by the presence of fat and the main substances transported by the lymph are fat. Apart from this content, it also contains protein and water in different amounts in blood plasma. The protein content in lymph is lower and the water content is much greater. Lymph flows through the lymph vessels and is not always in the lymph vessels, so it is called open blood circulation. Lymph circulation is not pumped by the heart like blood circulation but through contractions of skeletal muscles. Lymph or lymph functions in transporting fat from food and playing a role in the body's defense system (immune system). Interstitial fluid is the fluid that surrounds cells and includes fluid contained between body cavities. Lymph is composed of many lymphocytes and this is different from blood which is composed of red blood cells (erythrocytes), white blood cells (leukocytes) and platelets (thrombocytes). Humans have a blood circulatory system and a lymph (lymph) circulatory system. These two systems play an important role in the transportation of all substances or other components in the body. The lymph system consists of lymph fluid, lymph vessels and lymph nodes. 1. Lymph Fluid This lymph fluid contains white blood cells (leukocytes) which function to fight microorganisms or antigens that can cause infection (disease). This fluid comes out of the blood vessels and fills the spaces between cells so that it wets all body tissues. 2. Lymph vessels Lymph vessels or lymph vessels are part of the lymph circulation system. The lymph vessels function in maintaining the balance of body fluids, absorbing fat from the digestive tract and returning it to the blood circulation and providing protection or defense against infection by microorganisms. These vessels are different from blood vessels which circulate blood in a closed circulatory system, but these lymph vessels carry fluid in one direction. Lymph vessels are located between muscle cells, have fine branches, and are open at the ends. Through this tip, body fluids enter the lymph vessels. Lymph vessels are divided into two types, namely: a. Right lymph vessel This vessel functions to collect lymph fluid originating from the head and neck area right side, right chest, and right arm. This type of vessel ends in a vein (vein) which is under the right collarbone. b. Left lymph vessel This vessel functions to accommodate lymph originating from the head and neck area left, left chest, and left arm and lower body. This type of vessel ends in a vein (vein) below the left collarbone. 3. Lymph Glands Lymph nodes (lymph) or also known as lymph nodes are small, bean-shaped structures with a size of less than 2.5 cm. This gland plays a role in producing white blood cells and filtering lymph fluid before it is returned to the bloodstream. These glands can be found in the neck, thorax, abdomen and groin. Apart from that, there are also other organs related to the lymph system, namely the spleen and tonsils. The spleen is a gland located in the upper left abdominal cavity and just below the diaphragm. Lymph is dark purple in color and is the largest organ in the lymph system. The spleen produces lymphocytes so it plays an important role in the body's defense against disease and as a site for dismantling dead red blood cells. In addition, tonsils are one of the tissues in the lymph system. The tonsils are located just under the mucous membrane that lines the nose, mouth and throat (pharynx). The tonsils function to prevent infections caused by microorganisms that enter through the nose, mouth and throat.