Second-messenger mechanisms employing intracellular messengers and transduced by G proteins are a common means by which amino acid–based hormones interact with their target cells. Hormones alter cell activity by stimulating or inhibiting characteristic cellular processes of their target cells.Ĭell responses to hormone stimulation may involve changes in membrane permeability enzyme synthesis, activation, or inhibition secretory activity gene activation and mitosis. Most hormones are steroid or amino acid based. 7 Developmental Aspects of the Endocrine System.3 Interaction of Hormones at Target Cells.Local chemical messengers, not generally considered part of the endocrine system, include autocrines, which act on the cells that secrete them, and paracrines, which act on a different cell type nearby. [[Image:Illu endocrine system.png|right|thumb|The major endocrine glands: ( Male left, female right)ġ Pineal gland 2 Pituitary gland 3 Thyroid gland 4 Thymus 5 Adrenal gland 6 Pancreas 7 Ovary 8 Testes Other organs which are not so well known for their endocrine activity include the stomach, which produces such hormones as ghrelin. The hypothalamus is a neuroendocrine organ. The main endocrine glands include the adrenal glands, parathyroid glands, pineal body, pituitary gland, pancreas, ovaries, testes, thyroid gland, and.
Endocrine glands are glands of the endocrine system that secrete their products, hormones, directly into the blood rather than through a duct.
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