Endocrine system Endocrine system The endocrine system is a chemical messenger system consisting of hormones, the group of glands of an organism that secrete those hormones directly into the circulatory system to regulate the function of distant target organs, and the feedback loops which modulate hormone release so that homeostasis is maintained. In humans, the major endocrine glands are the thyroid gland and the adrenal glands. In vertebrates, the hypothalamus is the neural control center for all endocrine systems. The study of the endocrine system and its disorders is known as endocrinology. Endocrinology is a branch of internal medicine. Special features of
Multiple endocrine neoplasia mutation or hereditary transmission. The presence of two or more tumor types in a single patient does not automatically designate that individual as having MEN because there is a small statistical chance that development of two "sporadic" tumors that occur in one of the MEN syndromes could occur by chance. The term "multiple endocrine neoplasia" was introduced in 1968, but descriptions of the condition date back to 1903. Multiple endocrine neoplasia The term multiple endocrine neoplasia (MEN) encompasses several distinct syndromes featuring tumors of endocrine glands, each with its own characteristic pattern. In some cases, the tumors are malignant, in