Lymph nodes are small organs located along lymphatic vessels that store lymphocytes and antibodies to remove pathogens and cell debris, and also trap and destroy cancer cells. The thymus gland located in the upper mediastinum assists immune function and antibody development by changing lymphocytes into T cells using the hormone thymosin, and is most active until adolescence. Erythrocytes, or red blood cells, lack a nucleus, contain hemoglobin which gives them their red color, and the average adult has around 35 trillion with males having more than females.