Lecture 5 Chapter 45.3-45.5, 13 Book notes

Lecture 5 Chapter 45.3-45.5, 13 Book notes - Biology 110b...

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Biology 110b Chapter 45.3-45.5, 13 Book notes (Page 949) The hypothalamus and pituitary gland control much of the endocrine system. (Page 950) Hormone-secreting cells are present in many organs belonging to other systems. The hypothalamus plays an important role in integrating the vertebrate endocrine and nervous systems. This region on the underside of the brain: a. receives information from nerves throughout the body b. receives information from other parts of the brain c. initiates endocrine signals appropriate to environmental conditions The hypothalamus contains two sets of neurosecretory cells whose hormonal a secretions are stored in or regulate the activity of the pituitary gland , a lima bean-sized organ located at the base of the hypothalamus. The posterior pituitary , or neurohypophysis , is an extension of the hypothalamus that grows downward towards the mouth during embryonic development. It stores and secretes two hormones that are made by certain neurosecretory cells located in the hypothalamus; the long processes (axons) of these cells carry the hormones to the posterior pituitary. The anterior pituitary , or adenohypophysis , develops from a fold of tissue at the roof of the embryonic mouth; this tissue grows upward towards the brain and eventually loses its connection to the mouth. The anterior pituitary consists of endocrine cells that synthesize and secrete at lease six hormones. (Page 951) Hormones that regulate the function of endocrine organs, called tropic hormones , are particularly important in coordinating endocrine signaling throughout the body. The anterior pituitary is regulated by tropic hormones produced by a set of neurosecretory cells in the hypothalamus. Releasing hormones stimulate the anterior pituitary to release its hormones. Inhibiting hormones inhibit hormone secretion. The hypothalamic releasing and inhibiting hormones are secreted near capillaries at the base of the hypothalamus. The capillaries drain into short blood vessels, called portal vessels , that subdivide into a second capillary bed within the anterior pituitary. The posterior pituitary releases antidiuretic hormone (ADH) and oxytocin , which are both neurohormones.
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Biology 110b Chapter 45.3-45.5, 13 Book notes Antidiuretic hormone (ADH) acts on the kidneys increasing water retention and thus decreasing urine volume, helping to regulate the osmolarity of the blood. Oxytocin induces target cells in the uterine muscles to contract during childbirth. (Page 952) Three of the exclusively tropic hormones secreted by the anterior pituitary are closely related in their chemical structures. a. Follicle-stimulating hormone (FSH) b. Luteinizing hormone (LH) c. Thyroid-stimulating hormone (TSH) These are all glycoproteins , meaning they are protein molecules with carbohydrates attached to them. FSH and LH are also called
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This note was uploaded on 02/22/2009 for the course BSCI 110B taught by Professor Due during the Spring '08 term at Vanderbilt.

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Lecture 5 Chapter 45.3-45.5, 13 Book notes - Biology 110b...

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