© Copyright NewPath Learning. All Rights Reserved. 94-4939Visit www.newpathlearning.com for Online Learning Resources.The Endocrine SystemRole of the Endocrine SystemThe human endocrine system, like the nervous system, acts to control activity of cells and tissues of the body. While the nervous system works quickly, in milliseconds, the endocrine system functions more slowly, taking seconds or even days to make an impact through the release of chemicals into the bloodstream. How the Endocrine System FunctionsThe endocrine system consists of a variety of glands that release hormones. These hormones travel through the blood to cause an effect at some distant site. For example, when a person is frightened, the adrenal glands release adrenaline that travels to the heart and increases the heart rate.Endocrine GlandsEndocrine glands are spread out over the body. These glands all produce hormones. A complex system regulates the secretion of the hormones through a feedback mechanism. The “master gland” of this system is the pituitary. It releases many different hormones that control body and bone growth, water balance, and that help regulate many of the other endocrine glands. hypothalmuspinealpituitarythyroid &parathyroidadrenalglandspancreasthymussex organs(ovaries/testes)hormonesadrenalglandpancreas releasesinsulinpancreas stops releasinginsulinbloodglucosebloodglucosebody cells take up glucoseHomeostasisHormonesHormones are chemicals that can regulate functions and chemical reactions in the human body. For example, the growth hormone released by the pituitary gland increases bone growth. Insulin released by the pancreas helps control blood glucose levels. The thyroid releases thyroid hormone that helps regulate a wide range of chemical reactions in the body.Negative Feedback MechanismMost endocrine gland functions are controlled by a negative feedback mechanism that acts to turn off hormone release as a means of controlling hormone effects. For example, after a meal, when blood glucose levels go up, the pancreas releases insulin to bind to glucose to deliver it to vital body tissues. As cells of the pancreas sense a decrease in blood glucose, release of insulin is shut off. pituitaryhormonesThe human endocrine system, like the nervous system, acts to control activity of cells and tissues of the body. While the nervous system works quickly, in milliseconds, the endocrine systemfunctions more slowly, taking seconds or even days to make an impact through the release of chemicals into the bloodstream. The endocrine system consists of a variety of glandsthat release hormones. These hormones travel throughthe blood to cause an effect at some distant site. For example, when a person is frightened, the adrenal glands release adrenaline that travels to the heart and increases the heart rate.Endocrine glands are spread out over the body. These glannnnnddddddddddddsssssssssss aaaaaaaaaaaalllllllllllllll produce hormones. A complex system regulates the secretiiiiiiiiiiiiiooooooooooooonnnnnnnn offff tttthhhhhhhhhhhheeehormones through a feedback mechanism. The “master glaannnnnnnnnnnnnnnndddddddddddddd”””””””” oooooooooooofffffffffffffffff ttttttttthhhhhhhhhhhhhiiiiiiiiiiiissssssssss system is the pituitary. It releases many different hormoooones thhhhhhhhhhhhhaaaaaaaaaaaattttttttttttttt cccoooooooooooooonnnnnnnnnnnnnnnntrol body and bone growth, water balance, and that help rrrrrrrrrrreeeeeeeeeeeeeegggggggggguuuuulllllllllaaaaaaaaaattttttttttteeeeeeeeeee mmmmmmmmmmmmmaaaaaaaaaaaaaaannnnnnnnnyyyyyyyyyyyyyyyyyyy ooooooooooooooooffffffffffffff ttttttttthe other endocrine glands. hhhhhhhhhhhhyyyyyyyyyyyyyypppppppppppppoooooooooooootttttttttttttthhhhalmuspineaaaaaalllllllpituitarythhhyyyyyyyroiiiiiiiddddddddddddddddd &&&&&&&&&&&&&&&&ppaaaaaaaaaaarrrrrrrrrrrraaaaaaaaaaaaaaatttttttttttttttthhhhhhhhhhhhyyyyyyyyyyyyroiiiiiiiiidddddddddddadrenalgggggggggggggggglandspancreasttttttttttttttthhhhhhhhhhhhhyyyyyyyyyyyyyyymmmmmmmmmmmmmmuuuuuuuuuuuusssssssssssssex organs(ovaries/testes)hoooormmmmmooooneshoooooooooooooooorrrrmmmmmmmmmmmmmmmmooooooooadrrrrrrreeeeeeeeeeeeeeennaaaaaaaaaaaaaallllllnalllllllllllllggggggglllllllllllaaaaaaaaaannnddddddddddddddppppppaaaaaaaaaaaaannnnnnnnnnnnncccccrrrrrrrrrrrrreeeeeeeeeeas rreeeeeeeeeeeeelllllllllleeeeeeeeeeeaaaaaaseeeeeeeeeeesssssssssssssiiiiiiinnnnnnnnnnnnssssssssssssuuuuuuuuuulinppppppppppppppaaaaaaaaaaaannnnncreas stops rrrreleasinginsulinbbbbbbbbbbbbbbbllllllllooooooooooooddddddddddddddgggggggggggggggglllluuuccccccccccooooooooooooooossssssssssssssseeeeeeeeeeeeeeeebbbbbbllllllllloooooooooooooodgggggggggllllllllllluuuuuuuuuucosebbbbbbbbbbbbboooody cells take uuuuuuuuuuuupppppppppppppp glucoseHomeostasisHormones are chemicals that can reeeeeeeeeeggggggggggggguuuuuuuuuuuuuullllllllllllaaaaaaaaaate functions and chemical reactions iiiiiiiiiinnnnnnnnnnnnnn ttttttthehuman body. For example, the growttthhhhhhhhhhhhhh hormone released by the pituitary glandincreases bone growth. Insulin released by the pancreas helps control bbblllllllooooooooooooooooooooddddddddddddd glucose levels. The thyroiddddddddddddddddddd rrrrrrrrreeeeeeeelllllllllleases ttttthhhhhhhhhhhhyyyyyyyyyyyyyyyrrrrrrrrrroooooooooooiiiiiiiiddddddddddddd hormone that helps regulaaaaaaaaaaattttttttttteeeeeeeeeeeeeee aaaaa wwiiiiiiiiiiiddddddddddddddeeeeeeeeeeee rrrrrange of chemical reactions in the bbbbbbbbbbbooooooooooooodddddddddddddddyyyyyyyyyyyyyy....Most endocrine gland functions are controlled by a negative feedback mechanism that acts to turn off hormone release as a means of controlling hormoneeffects. For example, after a meal, when blood glucose levels go up, the pancreas releases insulinto bind to glucose to deliver it to vital body tissues. As cells of the pancreas sense a decrease in blood glucose, release of insulin is shut off. ppppppppppppppiiiiiiiittttttttttttuuuuuuuuuuiiiiiiiiiiiitttttttttttttttttaaaaaaaaryyyyyhormones
< Page 9 | Page 11 >