Presentation on theme: "Chapter 30 Organization and Control of the Endocrine System"— Presentation transcript:
1Chapter 30 Organization and Control of the Endocrine System
2HormonesHormones make cells react by attaching to receptors on their membranesA cell will only respond if it has receptors for the hormoneUp-regulation: the cell makes more hormone receptorsDown-regulation: the cell makes fewer hormone receptorsDifferent cells respond differently to the same hormone
3Hormones (cont.)Hormones can affect cells nearby or far away
4QuestionYour patient has low levels of circulating thyroid hormone. How will the cells of the thyroid gland respond?No responseResponse will depend upon the levels of TSH.Down-regulationUp-regulation
5AnswerUp-regulationRationale: When there is diminished hormonal activity, cells have the ability to make more hormone receptors and increase the sensitivity of the existing receptors to the hormone. This is called up-regulation.
6Hormones (cont.) Hormones can be made of: Amino acids Epinephrine, dopamine, T3, and T4Proteins (peptide hormones)Insulin, glucagon, trophic hormonesCholesterol (steroid hormones)Cortisol, aldosterone, testosteroneFatty acidsEcosanoids
7Question Tell whether the following statement is true or false. Steroid hormones are all derived from cholesterol.
8AnswerTrueRationale: The adrenal sex hormones, glucocorticoids, and mineralocorticoids all arise from cholesterol and have similar chemical structures even though their functions are slightly different.
9ScenarioA man takes dopamine for paralysis caused by his Parkinson disease.At first, a small dose of dopamine was all he neededHis symptoms improved significantly right after taking it, but then he froze up againNow he needs a high dose, and the effects last only a little whileQuestion:What has happened to his cells and their receptors?The doctor has decided to try giving him an MAO inhibitor along with his dopamine. Why?
10After Hormones Affect Body Cells They may be destroyed by enzymes at the receptor siteEpinephrine, dopamineThey may be taken up by cells and destroyedPeptide hormonesThey may be destroyed in the liver and passed out in the bileSteroid hormonesT3 and T4
11Scenario A man with liver failure has developed: Hypokalemia HypotensionHyperglycemiaRepeated infectionsQuestion:What hormone imbalances do you suspect? Why?
12Hypothalamus The hypothalamus knows the state of the body: Temperature Blood osmolarityBlood nutrientsBlood hormone levelsInflammatory mediators in bloodEmotionsPain
13The Hypothalamus Makes Releasing Hormones Releasing hormones are sent to the pituitary via the hypophyseal portal systemHypothalamusHypophyseal portal systemAnterior pituitary(Image reproduced from Bowne, P.S. . CRH release tutorial. Used with author’s permission.)
14The Pituitary (Master Gland) Creates Trophic Hormones Hypothalamus makes releasing hormonesThe Pituitary (Master Gland) Creates Trophic HormonesWhich are sent to the anterior pituitaryThe anterior pituitary releases its stored trophic hormones into the systemic circulationThey tell other endocrine organs in the body to grow and secrete their hormones(Image reproduced from Bowne, P.S. . CRH release tutorial. Used with author’s permission.)
16Question Tell whether the following statement is true or false. The pituitary gland controls the release of thyroid hormone.
17AnswerTrueRationale: The pituitary gland (on a cue from the hypothalamus) tells other organs or glands to produce and secrete or inhibit the appropriate hormones.
18Discussion A man’s hypothalamus has no hormone receptors. What will happen to his production of:CRH T3 and T4ACTH FSHCortisol LHTestosterone GnRHTRH TSHQuestion:What signs and symptoms do you expect him to have?