CH 7 introduction to the endocrine system

CH 7 introduction to the endocrine system - CH 7:...

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CH 7: INTRODUCTION TO THE ENDOCRINE SYSTEM In one example of diabetes - A seven year old had symptoms of o Increased appetite o Losing weight while eating more o Increased water intake, bed-wetting - Was diagnosed based on running testes to determine glucose concentration in the blood and urine o Had diabetes due to lack of insulin, a hormone produced by the pancreas o Thus, insulin injections must be administered for life Endocrinology - Is the study of hormones HORMONES Hormones are chemical messengers secreted into the blood by specialized cells - Are responsible for long-term, ongoing functions of the body - Influence growth and development, metabolism, regulation of the internal environment (temperature, water balance, ions), and reproduction - Hormones act on their target cells in one of three basic ways o By controlling the rates of enzymatic reactions o By controlling the transport of ions or molecules across cell membranes o By controlling gene expression and the synthesis of proteins HORMONES HAVE BEEN KNOWN SINCE ANCIENT TIMES Ancient art depicts evidence of endocrine abnormalities - One pre-Colombian statue of a woman shows a mass on the front of her neck
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CH 7: INTRODUCTION TO THE ENDOCRINE SYSTEM o The mass is an enlarged thyroid gland, or goiter , a common condition high in the Andes, where the dietary iodine needed to make thyroid hormones was lacking Classic hormones - Include hormones of the pancreas, thyroid, adrenal glands, pituitary, and gonads, all discrete endocrine glands that could be easily identified and surgically removed WHAT MAKES A CHEMICAL A HORMONE? Hormone - Is a chemical secreted by a cell or group of cells into the blood for transport to a distant target, where it exerts its effect at very low concentrations HORMONES ARE SECRETED BY A CELL OR GROUP OF CELLS Endocrine glands - Are the discrete and readily identifiable tissues derived from epithelial tissue - Secrete chemical messengers Isolated endocrine cells - Secrete molecules that act as hormones o i.e., hormones of the diffuse endocrine system , by neurons ( neurohormones ), and by cells of the immune system ( cytokines ) HORMONES ARE SECRETED INTO THE BLOOD Secretion - is the movement of a substance from the intracellular compartment either to the extracellular compartment or to the external environment - hormones are secreted into the blood and ectohormones are secreted into the external environment
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CH 7: INTRODUCTION TO THE ENDOCRINE SYSTEM Pheromones (to bring) - are specialized ectohormones that act on other organisms of the same species to elicit a physiological or behavioral response o i.e., ants release trail pheromones to attract fellow workers to food sources - attract members of the opposite sex for mating purposes o i.e., fruit flies and dogs Some studies have shown that humans have pheromones - i.e., the human axillary (armpit) sweat glands secrete volatile steroids related to sex hormones that may serve as human sex pheromones o When woman were asked to rate the odors of T-shirts worn by male
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This note was uploaded on 04/07/2008 for the course BIOL 425 taught by Professor Tondi during the Spring '08 term at George Mason.

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CH 7 introduction to the endocrine system - CH 7:...

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