Presentation on theme: "Chapter 31 Organization and Control of the Endocrine System"— Presentation transcript:
1Chapter 31 Organization and Control of the Endocrine System Essentials of PathophysiologyChapter 31 Organization and Control of the Endocrine System
2Pre lecture quiz true/false The endocrine system uses chemical substances called hormones as a means of regulating and integrating body functions.All hormones can cross the cell membrane.The hypothalamus controls the release of pituitary hormones.The pituitary gland has been called the master gland because its hormones control the function of many target glands and cells.Glucagon, insulin, and epinephrine receptors are examples of surface (second messenger) receptors.TF
3Pre lecture quiz Feedback Hypothalamus paracrine Receptors Hormones exert their action by binding to high-affinity _________________ located either on the surface or inside the target cells.Decreased hormone levels often produce an increase in receptor numbers by means of a process called _________________ ; this increases the sensitivity of the body to existing hormone levels.The ________________ and pituitary form a unit that exerts control over many functions of several endocrine glands as well as a wide range of other physiologic functions.Negative _________________ mechanisms regulate the level of many of the hormones in the body. Hormone secretions acting locally on cells other than those that produced the hormone is known as a ___________________ action.FeedbackHypothalamusparacrineReceptorsup-regulation
4Hormones make cells react by attaching to receptors on their membranes A 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
5Hormones (cont.) Hormones can affect cells nearby or far away Endocrine – distantParacrine – NearbyAutocrine – Self stimulating
6QuestionYour patient has low levels of circulating thyroid stimulating hormone. How will the cells of the thyroid gland respond?No responseResponse will depend upon the levels of TSH.Down-regulationUp-regulation
7AnswerUp-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.
8Hormones (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
9QuestionTell whether the following statement is true or false. Steroid hormones are all derived from cholesterol.
10AnswerTrue Rationale: The adrenal sex hormones, glucocorticoids, and mineralocorticoids all arise from cholesterol and have similar chemical structures even though their functions are slightly different.
11A man takes dopamine for paralysis caused by his Parkinson disease. ScenarioA 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?
12After 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
13A man with liver failure has developed: Hypokalemia Hypotension ScenarioA man with liver failure has developed:HypokalemiaHypotensionHyperglycemiaRepeated infectionsQuestion:What hormone imbalances do you suspect? Why?
14HypothalamusThe hypothalamus knows the state of the body:TemperatureBlood osmolarityBlood nutrientsBlood hormone levelsInflammatory mediators in bloodEmotionsPain
15The 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.)
16The Pituitary (Master Gland) Creates Trophic Hormones Hypothalamus makes releasing 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.)
19QuestionTell whether the following statement is true or false. The pituitary gland controls the release of thyroid hormone.
20AnswerTrue Rationale: The pituitary gland (on a cue from the hypothalamus) tells other organs or glands to produce and secrete or inhibit the appropriate hormones.
21Discussion 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?