Pituitary Gland
The pituitary gland consists of two distinct lobes called the anterior and posterior pituitary. Both of them are regulated by the hypothalamus. The anterior pituitary produces hormones used in the reproductive process. It produces Follicle-stimulating hormone (FSH) and lutinizing hormone (LH) which stimulate production of sperm and testosterone in males and of eggs, estrogen, and progesterone in females. The anterior pituitary gland interacts with the thyroid by producing the thyroid-stimulating hormone (TSH) which stimulates the thyroid to release its hormones. The anterior pituitary gland also interacts with the adrenal gland by producing the adrenocorticotropic hormone (ACTH) to cause it to release its hormones. The anterior pituitary gland also produces some hormones that do not interact with other endocrine glands:
The posterior pituitary acts in concert with the hypothalamus to release two peptide hormones that are synthesized in the hypothalamus. These two hormones are transported to the pituitary where they are transferred to capillary beds and travel in the bloodstream to their destinations. The antidiuretic hormone (ADH) increases the permeability to water of the collecting ducts of the nephrons of the kidney, causing water to be reabsorbed from the urine and retained in the body. This process acts as a negative feedback loop to control the content of water in the blood. The hormone oxytocin, synthesized in the hypothalamus and distributed in the blood by the pituitary, aids in lactation by nursing mothers by causing muscles in the breast to contract. This ejects milk from the saclike milk glands into the nipples. Oxytocin also causes contraction of the muscles of the uterus during childbirth. Oxytocin may also affect male reproductive behavior by causing contraction of the sperm-carrying tubes, as observed in several animal species.
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Index Reference Audesirk & Audesirk Ch 32 Thibodeau & Patton Ch 16 | ||||
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