endocrinology(内分泌总论)-课件.ppt

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1、Classical endocrine glands,Pineal（松果体）Pituitary（垂体）Thyroid（甲状腺）Parathyroid（甲状旁腺）Adrenal（肾上腺）Islets（胰岛）gonads（性腺）,Endocrineendo-crineendo-a combining form meaning“within,”used in the formation of compound words:endocardial;endocrinologycrine:paracrine autocrine exocrine,Endocrinology,With development

2、,the definition and scope of investigative and clinical endocrinology continues to expand.For example:heart,kidney,adipose tissue,Components of the endocrine and metabolic systems,Architectural and functional properties of endocrine and metabolic system,Endocrine system,Endocrine system consists of

3、two main parts:Endocrine glandsSporadic endocrine tissues and cells in non-endocrine organ,Hypothalamus-pituitary-target gland,Hypothalamus-pituitary,anterior pituitary releases six hormones:ACTH、TSH、FSH、LH、PRL、GHposterior pituitary releases two hormones that are actually produced in the hypothalamu

4、s:antidiuretic hormone(ADH)acts on the kidneys to conserve water and also promotes constriction of blood vessels.oxytocin stimulates uterine contractions and promotes milk“letdown”in the breasts during lactation.,An excess of growth hormone in children causes giantism.In adults it causes acromegaly.

5、dwarfism(lack of growth hormone).Excess ACTH overstimulates the adrenal cortex,resulting in Cushing disease.,Increased prolactin causes milk secretion,or galactorrhea,in both males and females.A specific lack of ADH from the posterior pituitary results in diabetes insipidus(polyuria and polydipsia).

6、,Hormones,PituitaryTSH，ACTH，GH，PRL，LH，FSHPeripheral glandThyroid：T3，T4Parathyroid：PTHAdrenal：cortisol、aldosteroneGonads：T，DHT，E，PLiver：IGFkidney：1，25(OH)2D3islets：insulin,glucagon（胰高血糖素）,Apart from these glands,there are many tissues and cells sparsely distributed in non-endocrine organs,such as the

7、 atrium of the heart,the liver,the kidney,the gastrointestinal tract and the adipose tissues.,Classification of hormone,Hormones are customarily divided into three groups:Proteins and peptides:insulin（蛋白质和肽类激素）Steroids:cortisol（类固醇激素）Amino acid analogues:T3,T4（氨基酸类激素）,Steroids,Tissues which produce

8、steroid hormones include ovary/testis,adrenal cortex,placenta and skin(vitamin D).All steroid hormones are based on the precursor molecule cholesterol.,Regulation of hormone levels,Spontaneous,or basal,hormone releaseFeedback inhibition by hormones of their synthesis and/or releaseStimulation or inh

9、ibition of hormone release by substances that may or may not be regulated by the same hormones,Establishment of circadian rhythms for hormone release by systems such as the brainBrain mediated stimulation or inhibition of hormone release in response to anxiety anticipation of a specific activity,or

10、other sensory inputs.,Hypothalamus-pituitary-adrenal axis,The hypothalamus produces CRH,which travels down the portal vessels through the hypothalamic stalk to the anterior pituitary,where it stimulates ACTH release.ACTH then travels to the adrenal gland,where it stimulates the release of cortisol.,

11、Cortisol in turn inhibits both CRH and ACTH release（feedback inhibition）.The brain establishes circadian rhythms and can trigger increased CRH release in response to stress.,CRH,ACTH,cortisol,Mechanisms of hormone action,Peptide and catecholamine hormones and prostaglandins bind to receptors on the

12、cell surface.Steroid and thyroid hormones act for the most part by binding to intracellular receptors.,binding to receptors on the cell surface,binding to intracellular receptors,hormones bind to receptors on the cell surface,Peptide and catecholamine hormones and prostaglandins bind to receptors on

13、 the cell surface,where the hormone-receptor interactions affect intracellular mediators,or second messengers.,Second messengers,cAMP:Glucagon,ACTH,PTHProtein kinase activityInsulinCalcium Alpha-adrenergic agonists,AT II phospholipidsADH,GnRH,TRH.,hormones bind to receptors on the cell surface,bindi

14、ng to intracellular receptors,intracellular receptors,Disorders of the endocrine and metabolic system,Most recognizable disorders of the endocrine system are due to an excess or a deficiency of particular hormones,whether caused by abnormalities of endocrine glands,ectopic production of hormones,abn

15、ormal conversion of prohormones to their active forms,or iatrogenic factors.,Hypofunction of endocrine glands,Endocrine glands may be injured or destroyed by neoplasia,infections,hemorrhage,autoimmune disorders,and other causes.,Hormone deficiency secondary to extraglandular disorders,Impaired conve

16、rsion of a prohormone to a hormone occurs in chronic renal failure,in which there is defective conversion of 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol.,Hyporesponsiveness to hormones,Hormone levels may be normal or even elevated in the presence of manifestations of endocrine deficie

17、ncy.,Hormone exess syndrome,Hyperfunction of endocrine glandsEctopic hormone productionHormone administrationTissue hypersensitivity,Hyperfuction of endocrine glands,The most common cause of hormone excess syndromes is hyperfunction of endocrine glands secondary to tumors of the glands or hyperplasi

18、a of several causes.,Metabolic disorders,Diabetes mellitusHypoglycemiaHyperuricemia and goutDisorders of lipid metabolismNutritional/vitamin deficiencies,Symptoms and signs of endocrine and metabolic diseases,Hormones affect the function of all tissues and organ systems.Consequently,the symptoms and

19、 signs of endocrine disease are extremely diverse.They may vary from generalized,such as fatigue,to localized,such as weakness of the extraocular muscles.,Generalized symptomes,Weakness and fatigueMental changesUnintended weight lossWeight gainAbnormal body temperature,Hypersecretion of Adrenal Cort

20、ex,Symptomes,Ophthalmic abnormalitiesAbnormal skin pigmentationHirsutismGynecomastiaGalactorrheaAbnormal appetiteDiarrhea,Symptomes,AnemiaTachycardia and bradycardiaPolyuriaAmenorrhea or oligomenorrheaInfertilityBone pain and pathologic fracture,Hyposecretion of TH,GH=pituitary dwarfism,Physical and

21、 laboratory examination and diagnosis,History and physical examination,Many syndromes of hormonal excess or deficiency display manifestations that are readily apparent at the time of initial presentation,e.g.,severe thyrotoxicosis and cushings syndrome.In other instances,the clinial presentation is

22、more subtle and the physician must rely on laboratory testing to establish a diagnosis.,Laboratory testing,The level of free rather than total hormone is usually the best index of the effective hormone concentration in plasma.A measurement of the 24-h urine free cortisol usually provides a reasonabl

23、e estimate of the integrated levels of free plasma hormone.,正常人,2400 0800 1600,库欣病患者,2400 0800 1600,正常人和库欣患者的血F昼夜节律,Clinical interpretation,The clinicians must remember that in both mormal subjects and patients with endocrine and other diseases,hormone levels are extensively regulated.For instance,p

24、lasma insulin levels should be evaluated in relation to the plasma glucose concentration,and PTH levels should be considered in relation to serum calcium levels.,Clinical interpretation,Since cortisol production integrated over a 24-h period is increased in cushings syndrome,the 24-h urinary free co

25、rtisol provides a more accurate index of cortisol hypersecretion.,Clinical interpretation,Sometimes the significance of hormone levels can be evaluated only by the simultaneous measurement of more than one hormone.For instance,with progressive damage to the thyroid hormones,secretion of TSH increase

26、s in a compensatory fashion so that normal plasma levels of the thyroid hormones may be maintained.,GD的自身免疫发病机制,Clinical interpretation,Plasma estrogens are low in ovarian failure.If ovarial failure is due to disease of the ovary,plasma gonadotropins will be elevated.If ovarian failure is secondary

27、to pituitary or hypothalamic disease,plasma gonadotropin levels will be normal or decreased.,Dynamic testing,Provocative testing assesses the ability of a gland to respond to stimuli as an index of its reserve capacity.Insulin induced hypoglycemia is used to assess the secretory ability of cells tha

28、t produce growth hormone.,Tests that provide indirect information,Diagnosis of diabetes mellitus and assessment of therapy depend on measurement of plasma glucose rather than insulin levels.It is helpful to follow the serum calcium levels in hyperparathyroidism and the serum potassium levels in prim

29、ary aldosteronism.,Tests that provide indirect information,For instance,serum sodium is almost always greater than 139mEq/liter in patients with an aldosterone producing adenoma,plasma cholesterol tends to be high in hypothyroidism and low in hyperthyroidism.,Treatment of endocrine and metabolic dis

30、ease,For endocrine deficiency syndromes,hormones are generally administered to counter the deficiency.,Vitamin D is given instead of PTH to treat hypoparathyroidism,since it can increase the extracellular Ca+.,In cases in which hormone resistance is present,steps are taken when possible to alleviate

31、 this,such as through diet restriction in type 2 diabetes.,In hormone-excess syndromes,a variety of approaches are used.Hyperfuctioning tumors are removed or destroyed with radiotherapy when possible,and sometimes hyperplastic glands are removed.,In other cases drugs are given to block hormone production and release,such as methimazole/propylthiouracil for thyrotoxicosis and cabergoline/bromocriptine for prolactin-producing adenomas.,Antagonists such as spironolactone can some times be useful in primary aldosteronism due to hyperplasia.,