Spider monkeys are among the largest New World monkeys; black-headed spider monkeys, the largest spider monkey, have an average weight of 11 kilograms (24 lb) for males and 9.66 kg (21.3 lb) for females.
IMMUNE SYSTEM. -responsible for protecting the body against bacteria, viruses, fungi, toxins, parasites, and cancer. -works with organs of lymphatic system, thymus, spleen, and lymph nodes, to clear body of these disease causing agents. LYMPHATIC SYSTEM.
Parathyroid glands are small glands of the endocrine system which are located in the neck behind the thyroid. Parathyroid glands control the calcium in our bodies--how much calcium is in our bones, and how much calcium is in our blood. Calcium is the most important element in our bodies (we use it to control many systems), so calcium is regulated very carefully. Parathyroid glands control the calcium.