The lymphatic system
The lymphatic system is an extensive drainage network that is closely connected to both the circulatory and immune systems. It is responsible for keeping bodily fluids in balance and defends the body against infections. It is made up of a network of very small tubes known as lymphatic vessels that carry lymph, a colourless fluid that contains a high number of white blood cells and resembles plasma, throughout the body. The major parts of the lymph tissue are located in the bone marrow, spleen, thymus gland, lymph nodes, and the tonsils.
One of the lymphatic system's major roles is to collect extra lymph fluid from body tissues and return it to the blood. This process is crucial because, during the course of the day, around 21 litres of fluid from the plasma, carrying dissolved substances and some plasma protein, escapes from the capillaries of the circulatory system and into the tissues. Most of this fluid is returned directly to the blood stream via the capillary, but 3-4 litres of fluid are drained away by the lymphatic vessels. If the lymphatic system didn't drain the excess fluid from the tissues, the lymph fluid would build up in the body's tissues and would cause them to swell.
The lymphatic system also helps defend the body against germs like viruses, bacteria, and fungi that can cause illnesses. Those germs are filtered out in the lymph nodes, which are small masses of tissue that are located along the network of lymph vessels. Most of the lymph nodes are found in clusters in the neck, armpit, and groin area. Nodes are also located along the lymphatic pathways in the chest, abdomen, and pelvis, where they filter the blood. The lymph nodes are oval, bean shaped organs which contain concentrated areas of lymphocytes, a type of white blood cell, and macrophages. The lymphocytes produce chemicals called antibodies, special proteins that fight off germs and prevent infections from spreading, which kill micro-organisms in various ways, either by surrounding the
One of the lymphatic system's major roles is to collect extra lymph fluid from body tissues and return it to the blood. This process is crucial because, during the course of the day, around 21 litres of fluid from the plasma, carrying dissolved substances and some plasma protein, escapes from the capillaries of the circulatory system and into the tissues. Most of this fluid is returned directly to the blood stream via the capillary, but 3-4 litres of fluid are drained away by the lymphatic vessels. If the lymphatic system didn't drain the excess fluid from the tissues, the lymph fluid would build up in the body's tissues and would cause them to swell.
The lymphatic system also helps defend the body against germs like viruses, bacteria, and fungi that can cause illnesses. Those germs are filtered out in the lymph nodes, which are small masses of tissue that are located along the network of lymph vessels. Most of the lymph nodes are found in clusters in the neck, armpit, and groin area. Nodes are also located along the lymphatic pathways in the chest, abdomen, and pelvis, where they filter the blood. The lymph nodes are oval, bean shaped organs which contain concentrated areas of lymphocytes, a type of white blood cell, and macrophages. The lymphocytes produce chemicals called antibodies, special proteins that fight off germs and prevent infections from spreading, which kill micro-organisms in various ways, either by surrounding the