The lymphatic system transports lymph fluid through vessels called lymphatic capillaries from tissues back to the bloodstream. It helps control microorganisms and transports fat and immune cells. The lymphatic system includes lymph, lymph nodes, lymph vessels, and lymphatic organs like the spleen, thymus gland, tonsils, and Peyer's patches. The spleen filters blood and stores blood cells, while the thymus gland and tonsils help produce immune cells. Together these organs help the body fight pathogens and develop immunity.