Major glands of the human endocrine system. The hypothalamus stimulates the pituitary gland and elipsis
Group of ductless gland
s that secrete hormone
s necessary for normal growth and development, reproduction, and homeostasis
. The major endocrine glands are the hypothalamus
s, islets of Langerhans
in the pancreas
, and testes
. Secretion is regulated either by regulators in a gland that detect high or low levels of a chemical and inhibit or stimulate secretion or by a complex mechanism involving the hypothalamus and the pituitary. Tumour
s that produce hormones can throw off this balance. Diseases of the endocrine system result from over- or underproduction of a hormone or an abnormal response to a hormone.
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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.