The circulatory pathway of lymph is a one-way flow from the intestinal area to the base of the neck. Lymph absorbs harmful debris and pathogens on its journey upward. These pathogens are removed from the lymph by the lymph nodes and then expelled from the body.
The filtered lymph then enters the venous bloodstream through the subclavian veins, which are located at the base of the neck, and becomes part of the circulatory system's venous blood. The lymphatic system consists of lymph, lymph nodes, lymph vessels, tonsils, spleen and thymus. Lymph is a clear, colorless fluid. Lymph contains white blood cells, which fight infection. The human body contains approximately 600 to 700 lymph nodes.
When the lymph nodes detect bacteria in the lymph, they produce additional white blood cells to fight the infection. This immune response often causes swelling of the lymph nodes, especially in the neck. The tonsils are a large cluster of lymphatic cells located in the pharynx. Tonsils are sometimes removed from patients who suffer from chronic sore throats. T-cells, which help destroy infected and cancerous cells, grow in the thymus. The spleen contains bacteria-fighting white blood cells. Spleens are often surgically removed due to a variety of health conditions. Patients who have their spleens removed live normal lives, though they are more susceptible to infection.