The lymphatic circulation is a one way blind ended system, which directs tissue fluid back to the systemic circulation. The thoracic ducts empty tissue fluid into the blood stream, at the subclavian veins. It is an endocrine gland which secretes hormones regulating lymphocyte maturation. The T lymphocytes mature in this organ. It clears old and damaged red blood cells.
Macrophages clean up debris and bacteria.
It is a holding station for large numbers of lymphocytes. Macrophages here clear lymph of bacteria and cellular debris. It rests only between beats. The heart is two pumps, divided by a septum. The right side pumps blood to the lungs.