Chapter 10 Endocrinology Teachering Hours 7 hours Intensive Teaching:Mechanisms of hormonal action and regulation of hormonal secretion;Functions of hypothalamus and pituitary hormones,thyroid hormone, insulin.adrenal medulla and cortex hormones,sex hormones. Nodi for student:1.Mechanisms of hormonal action and regulation of hormonal secretion 2.Structure ofhypothalamus and pituitary 3.Function of neurohypophysis,adenohypophysial and hypothalamus hormones Seaction1 Introduction 1.Endocrine system The endocrine system can be defined as the endocrine glands and cells of the body. It is one of the two coordinating and integrating systems of the body,which acts through chemical messengers (hormones)carried in the circulation and is involved in many functions,such as maintenance of the internal environment,control of the storage and utilization of energy enviroment,regulation of growth,development and reproduction,and the body's responses to environmental stimuli. 2.Hormone A hormone is a chemical produced by endocrine glands or endocrine cells in a small amount that is released into the blood stream to act on cells in a distant tissue. Classifition:(1)nitrogenous hormones(2)steroid (3)fatty acid derivatives
Chapter 10 Endocrinology Teachering Hours ：7 hours Intensive Teaching：Mechanisms of hormonal action and regulation of hormonal secretion; Functions of hypothalamus and pituitary hormones, thyroid hormone, insulin, adrenal medulla and cortex hormones,sex hormones. Nodi for student：1. Mechanisms of hormonal action and regulation of hormonal secretion 2. Structure of hypothalamus and pituitary 3. Function of neurohypophysis, adenohypophysial and hypothalamus hormones Seaction1 Introduction 1. Endocrine system The endocrine system can be defined as the endocrine glands and cells of the body. It is one of the two coordinating and integrating systems of the body, which acts through chemical messengers (hormones) carried in the circulation and is involved in many functions, such as maintenance of the internal environment, control of the storage and utilization of energy enviroment, regulation of growth, development and reproduction, and the body’s responses to environmental stimuli. 2. Hormone A hormone is a chemical produced by endocrine glands or endocrine cells in a small amount that is released into the blood stream to act on cells in a distant tissue. Classifition: (1) nitrogenous hormones(2) steroid (3) fatty acid derivatives
3.The common characteristics of action of hormone (1)Effect of message transmission to regulate the physiological and biochemical responses (2)Relative specificity ofhormone effect (3)Stronger biological amplification ofhormones (4)Interaction between hormones:1 Cooperation 2 Antagonism3 Permissive action 4.Mechanisms of hormonalaction 4.1 nitrogenous hormones:Second messenger hypothesis DHormone combines with specific receptor on surface of cell membrane and forms a hormone-receptor complex. 2The hormone-receptor complex activates thethe adenyl cyclase(AC)in the membrane. 3ATP is conversed into cAMP with the catalysis ofAC As the second messenger,cAMPactivates protein kinase 5 activated protein kinase initiates a series of physiological responses. 4.2 steroids:the gene expression hypothesis Dsteroid hormone enters cell as a lipid soluble hormone and combines with specific cytosol receptor to form steroid-receptor complex. 2This steroid-receptor complex passes into the nucleus to combine with DNA,and activates the formation ofmRNA. 3The mRNA diffuses into the cytoplasm where it promotes the translation process
3. The common characteristics of action of hormone (1) Effect of message transmission to regulate the physiological and biochemical responses (2) Relative specificity of hormone effect (3) Stronger biological amplification of hormones (4) Interaction between hormones: ① Cooperation ② Antagonism③ Permissive action 4. Mechanisms of hormonal action 4.1 nitrogenous hormones: Second messenger hypothesis ①Hormone combines with specific receptor on surface of cell membrane and forms a hormone-receptor complex. ②The hormone-receptor complex activates the the adenyl cyclase(AC) in the membrane. ③ATP is conversed into cAMP with the catalysis of AC ④As the second messenger,cAMP activates protein kinase ⑤ activated protein kinase initiates a series of physiological responses. 4.2 steroids: the gene expression hypothesis ①steroid hormone enters cell as a lipid soluble hormone and combines with specific cytosol receptor to form steroid-receptor complex. ②This steroid-receptor complex passes into the nucleus to combine with DNA,and activates the formation of mRNA. ③The mRNA diffuses into the cytoplasm where it promotes the translation process
at the ribosomes to form new proteins.Induce physiological effect. 5.Control ofhormone secretion (1)Nervous regulation:control of nervous system to endocrine system;effect of environment on endocrine system (2)Hormonal regulation:feedback control of hormone secretion by metabolic products; Feedback control ofhormone secretion by hormone. Seaction2 Hypothalamus and Pituitary 1.Relations of hypothalamus and pituitary in structure and function 2.Functions of neurohypophysis hormones (1)ADH(or vasopressin):i)increase reabsorption ofH2O in kidney. ii)Induce constriction of vascular smooth muscle;increase blood press (2)OXT:pormoting constrictionofuterus 3.Hypothalamic hormnes (1)CRH:stimulates secretionofACTH (2)TRH:stimulates secretion ofTSH (3)GnRH:stimulates secretion ofLH and FSH (4)GHRH:stimulates secretion ofGH (5)GHRIH:inhibits secretionofGH (6)PRH,PIH,MRF.MIF 4.Adenohypophysial hormones
at the ribosomes to form new proteins. Induce physiological effect. 5.Control of hormone secretion (1) Nervous regulation: control of nervous system to endocrine system; effect of environment on endocrine system (2)Hormonal regulation: feedback control of hormone secretion by metabolic products; Feedback control of hormone secretion by hormone. Seaction2 Hypothalamus and Pituitary 1. Relations of hypothalamus and pituitary in structure and function 2. Functions of neurohypophysis hormones (1)ADH (or vasopressin): i) increase reabsorption of H2O in kidney. ii) Induce constriction of vascular smooth muscle; increase blood press (2)OXT: pormoting constriction of uterus 3. Hypothalamic hormnes (1)CRH: stimulates secretion of ACTH (2)TRH: stimulates secretion of TSH (3)GnRH: stimulates secretion of LH and FSH (4)GHRH: stimulates secretion of GH (5)GHRIH: inhibits secretion of GH (6)PRH, PIH, MRF, MIF 4. Adenohypophysial hormones
(1)FSHand LH FSH:i)stimulate development and growth of follicle and testis; ii)stimulates follicle secretion and gametogenesis LH:i)stimulates follicle maturity and ovulation; ii)induce corpus luteum formation and secretes progesterone; iii)stimulates development of leydigs cells of testis and promotes secretion of androgen (2)PRL:regulates breast growth and milk synthesis;Permissive for certain reproductive function (3)ACTH:stimulatesadrenal steroids secretion (4)TSH:stimulates thyroid hormones secretion;regulates thyroid gland (5)GH:i)promotetissue growth ii)effect on metabolism:increase protein deposition,increase fat utilization, decrease carbohydrate utilization,increase blood glucose. 5.Regulation of adenohypophysial hormones secretion (1)Hypothalamic hormnes (2)feedback regulation Seaction3 Thyroid 1.Thyroid hormone (1)including thyroxin(T4),3,5,3 ,5 '-triiodothyronine(T3) (2)Synthesis and secretion ofthyroid hormones i)lodine is required for formation ofthyroxin
(1) FSH and LH FSH: i) stimulate development and growth of follicle and testis; ii) stimulates follicle secretion and gametogenesis LH: i) stimulates follicle maturity and ovulation; ii)induce corpus luteumformation and secretes progesterone; iii)stimulates development of leydigs cells of testis and promotes secretion of androgen (2)PRL: regulates breast growth and milk synthesis; Permissive for certain reproductive function (3)ACTH: stimulates adrenal steroids secretion (4)TSH:stimulates thyroid hormones secretion; regulates thyroid gland (5)GH: i) promote tissue growth ii) effect on metabolism: increase protein deposition, increase fat utilization, decrease carbohydrate utilization, increase blood glucose. 5. Regulation of adenohypophysial hormones secretion (1) Hypothalamic hormnes (2)feedback regulation Seaction3 Thyroid 1. Thyroid hormone (1) including thyroxin(T4),3,5,3‘,5‘-triiodothyronine(T3) (2) Synthesis and secretion of thyroid hormones i) Iodine is required for formation of thyroxin
2.Physicological functions of thyroid hormones (1)Effect of TH on metabolism 1increase the metabolic activities ofalmost all the tissue ofthe body 2 stimulation ofcarbohydrate:enhance glycolysis and enhance gluconeogenesis 3Effect on protein metabolism:Normal state:to activate synthesis ofproteins Increased secretion:to activate catabolismofproteins 4Stimulation of fat metabolism:Enhance all aspects of fact metabolism;mobilized lipids from fat tissue;decreased the fat stores ofbody (2)Effect of TH on growth D promote development ofnervoussystem 2Stimulates growth and development ofbones 3 maintain normal procreation (3)other effect of TH Having chronotropic and inotropic action on the heart 3.Regulation of thyroid hormone secretion (1)Hypothalamus-pituitary-thyroidaxis Hypothalamus secretes thyrotrop in-releasing hormone (TRH)-pituitary gland secretes thyroid-stimulating hormones (TSH)-thyroid gland secretes T4 and T3- induce physiological functions (2)L2 (3)Effects ofother hormones on secretion ofTSH Estrin increase the response ofpituitary gland to TRH-TSH t
2. Physicological functions of thyroid hormones (1) Effect of TH on metabolism ① increase the metabolic activities of almost all the tissue of the body ② stimulation of carbohydrate: enhance glycolysis and enhance gluconeogenesis ③ Effect on protein metabolism:Normal state: to activate synthesis of proteins Increased secretion: to activate catabolismof proteins ④Stimulation of fat metabolism: Enhance all aspects of fact metabolism; mobilized lipids from fat tissue; decreased the fat stores of body (2) Effect of TH on growth ① promote development of nervous system ② Stimulates growth and development of bones. ③ maintain normal procreation (3)other effect of TH Having chronotropic and inotropic action on the heart 3. Regulation of thyroid hormone secretion (1) Hypothalamus-pituitary-thyroid axis Hypothalamus secretes thyrotropin-releasing hormone (TRH)→ pituitary gland secretes thyroid-stimulating hormones (TSH) → thyroid gland secretes T4 and T3→ induce physiological functions (2)I2 (3) Effects of other hormones on secretion of TSH Estrin increase the response of pituitary gland to TRH→ TSH↑
GH and cortisol inhibit the secretion ofTSH Seaction4 Hormones Regulating Calcium Metabolism 1.Parathyroid hormone(PTH) PTH is secreted by the parathyroid glands.The action of PTH is to increase the plasma Ca2+and depress the plasma phosphate by mobilization of Ca2+from bone, increased urinary phosphate excretion,promotion of the formation of 1,25-(OH)2D3 and Ca2+absorption from the intestine. 2.Calcitonin(CT) CT secreted by thyroid gland decreases the circulating calcium and phosphate levels by inhibiting bone Ca2+absorption and increasing uric Ca2+excretion. 3.1,25-(0H02D3 1,25-(OH)2D3 is formed in the kidneys.Its actions are to increase Ca2+absorption from the intestine and Ca2+reabsorption in the kidneys. 4.Regulation of PTH,CT,and 1,25-(OH)2D3 secretion (1)The secretion ofPTH is inhibited by circulating Ca2+ (2)Plasma CT is directly proportionate to plasma Ca2+ (3)Formation of 1,25-(OH)D3 is regulated in a feedback fashion by plasma Ca2+ and PO43-,and facilitated by PTH,GH and CT Seaction5 Pancreatic Islets 1.Types of cells in pancreatic islets A cells:secrete Glucagon B cells:insulin
GH and cortisol inhibit the secretion of TSH Seaction4 Hormones Regulating Calcium Metabolism 1. Parathyroid hormone (PTH) PTH is secreted by the parathyroid glands. The action of PTH is to increase the plasma Ca2+ and depress the plasma phosphate by mobilization of Ca2+ from bone, increased urinary phosphate excretion, promotion of the formation of 1,25-(OH)2D3 and Ca2+ absorption from the intestine. 2. Calcitonin (CT) CT secreted by thyroid gland decreases the circulating calcium and phosphate levels by inhibiting bone Ca2+ absorption and increasing uric Ca2+ excretion. 3. 1，25-(OH)2 D3 1, 25-(OH)2D3 is formed in the kidneys. Its actions are to increase Ca2+ absorption from the intestine and Ca2+reabsorption in the kidneys. 4. Regulation of PTH, CT, and 1, 25-(OH) 2D3 secretion (1) The secretion of PTH is inhibited by circulating Ca2+ (2) Plasma CT is directly proportionate to plasma Ca2+ (3) Formation of 1, 25-(OH)2D3 is regulated in a feedback fashion by plasma Ca2+ and PO43-, and facilitated by PTH, GH and CT Seaction5 Pancreatic Islets 1. Types of cells in pancreatic islets A cells: secrete Glucagon B cells: insulin
D cells:Somatostatin PP cells:pancreatic polypeptide 2.Physicological functions of insulin (1)Effects on carbohydrate metabolism Increase uptake,storage and use of glucose;Increase glycogen synthesis;Decrease gluconeogenesis;decreases plasma glucose. (2)Effects on fat metabolism Increase conversion ofglucose into FA;Decrease lipodieresis (3)Effects on protein metabolism Increase protein synthesis;Decrease protein catabolism;Increase cell growth. 3.Regulation of insulin secretion (1)Plasma glucose increased,stimulated insulin secretion (2)Nervous regulation Feeding center (+ stimulated insulin secretion Vagus nerve(+) stimulated insulin secretion Sympathetic nerve(+) inhibited insulin secretion (3)Hormonal regulation Pepstatin stimulated insulin secretion;Glucagon stimulated insulin secretion 4.Glucagon Glucagon is produced by A cells of the pancreatic islets,when the blood glucose concentration falls.Its functions are opposed to those of insulin.Most important of these functions is to increase the blood glucose concentration by glycogenolysis and
D cells: Somatostatin PP cells: pancreatic polypeptide 2. Physicological functions of insulin (1)Effects on carbohydrate metabolism Increase uptake, storage and use of glucose; Increase glycogen synthesis; Decrease gluconeogenesis; decreases plasma glucose. (2) Effects on fat metabolism Increase conversion of glucose into FA; Decrease lipodieresis (3) Effects on protein metabolism Increase protein synthesis; Decrease protein catabolism; Increase cell growth. 3. Regulation of insulin secretion (1) Plasma glucose increased, stimulated insulin secretion (2) Nervous regulation Feeding center (+) stimulated insulin secretion Vagus nerve (+) stimulated insulin secretion Sympathetic nerve (+) inhibited insulin secretion (3)Hormonal regulation Pepstatin stimulated insulin secretion; Glucagon stimulated insulin secretion 4. Glucagon Glucagon is produced by A cells of the pancreatic islets, when the blood glucose concentration falls. Its functions are opposed to those of insulin. Most important of these functions is to increase the blood glucose concentration by glycogenolysis and
glyconeogenesis.Glucagon also increases ketone body formation and stimulates the secretion of GH,insulin,and pancreatic somatostatin.The factors stimulating glucagon secretion are amino acids,CCK,gastrin,cortisol,exercise,infection and physiological stresses;factors causing inhibition of glucagons release include glucose, somatostatin,secretin,FFA,ketones,insulin and GABA Seaction6 Adrenal Gland 1.Structure of adrenal gland Adrenal medulla:secrete NE and N Adrenal cortex:(1)zona glomerulosa:secret aldosterone (2)zona fasciculata :secret glucocorticoid,include cortisol and corticosterone (3)zona reticularis:secret sex hormone 2.The adrenocortical hormones 2.1 Aldosterone:reserve Na+excret K+ 2.2 Functions ofglucocorticoid 1Effects on metabolism: Protein:decreasing protein synthesis and increasing catabolism ofprotein Fat:increase oxidation and use offatty acids Carbohydrate:elevatation of blood glucose concentration by stimulation of gluconeogenesis and decreased glucose utilization in the cell 2Effects on organ system i)Vascular system:increased blood press
glyconeogenesis. Glucagon also increases ketone body formation and stimulates the secretion of GH, insulin, and pancreatic somatostatin. The factors stimulating glucagon secretion are amino acids, CCK, gastrin, cortisol, exercise, infection and physiological stresses; factors causing inhibition of glucagons release include glucose, somatostatin, secretin, FFA, ketones, insulin and GABA Seaction6 Adrenal Gland 1. Structure of adrenal gland Adrenal medulla: secreteNE and N Adrenal cortex: (1) zona glomerulosa: secret aldosterone (2) zona fasciculata :secret glucocorticoid,include cortisol and corticosterone (3) zona reticularis: secret sex hormone 2. The adrenocortical hormones 2.1 Aldosterone: reserve Na+ excret K+ 2.2 Functions of glucocorticoid ①Effects on metabolism: Protein: decreasing protein synthesis and increasing catabolism of protein Fat: increase oxidation and use of fatty acids Carbohydrate: elevatation of blood glucose concentration by stimulation of gluconeogenesis and decreased glucose utilization in the cell ②Effects on organ system i) Vascularsystem: increased blood press
ii)Gastrointestinal system:stimulates digestive secretions iii)Blood:Increased the quantity ofRBC,platelets and blasma proteins. 3resistance to stress and inhibitionofthe inflammatory response 2.3 Regulation ofadrenocortical hormones secretion (1)Regulation ofaldosterone secretion (2)Regulation ofglucocorticoid secretion 3.Adrenal medulla The adrenal medulla secrets the catecholamines including epinephrine, norepinephrine 3.1 Functions ofadrenal medulla hormones (1)Cardiovascular effects: (2)Metabolic effects:Increase blood glucose;Stimulates oxidation and lipodieresis;Increase BMR 3.2 Regulation Sympathetic nervous system controlled Seaction7 Gonad 1.Endocrine function of testis and its'regulation 1.1 Functions ofandrogen (1Required for initiation and maintenance of spermatogenesis;Induces differentiation ofmale accessory reproductive organs and maintains their function (2)Induce and maintain secondary sex characters ofmale animal. (3)Induce libido of male animal
ii) Gastrointestinalsystem: stimulates digestive secretions iii) Blood: Increased the quantity of RBC, platelets and blasma proteins. ③ resistance to stress and inhibition of the inflammatory response 2.3 Regulation of adrenocortical hormones secretion (1)Regulation of aldosterone secretion (2)Regulation of glucocorticoid secretion 3. Adrenal medulla The adrenal medulla secrets the catecholamines ， including epinephrine, norepinephrine 3.1 Functions of adrenal medulla hormones (1) Cardiovascular effects: (2) Metabolic effects: Increase blood glucose; Stimulates oxidation and lipodieresis; IncreaseBMR 3.2 Regulation Sympathetic nervous system controlled Seaction7 Gonad 1. Endocrine function of testis and its’regulation 1.1 Functions of androgen (1)Required for initiation and maintenance of spermatogenesis; Induces differentiation of male accessory reproductive organs and maintains their function. (2) Induce and maintain secondary sex characters of male animal. (3)Induce libido of male animal
(4)Stimulates protein anabolism (5)Stimulates formationofRBC in bone marrow (6)Increased excitility ofnervous system 1.2 Regulation oftesticular secretion 2.Endocrine function of ovary 2.1 Hormones secreted in ovary:estrogen and progestogen.Estrogen includes estradiol,estrone and estriol. 2.2 Functions ofestrogen (1)Induces development offemale accessory reproductive organs. (2)Induce and maintain secondary sex characters (3)Induce libido and sex behavior (4)Stimulates breast development (5)Induce porliferation of oviduct mucous membrane;Stimulate constriction of oviduct smooth muscle (6)Increased reabsorption ofH2O,Na',and Ca2+in kidney. 2.3 Functions ofprogestogen (1)Effects on uterus:Promoting secretary changes in the uterine endometrium; Decrease the sensibility ofuterus muscle to stimulatus. (2)Effects on breast:promoting developing ofbreast (3)Inhibit ovulation (4)Induce maternal behavior (5)Effect on body temperature
(4)Stimulates protein anabolism (5)Stimulates formation of RBC in bone marrow (6)Increased excitility of nervous system. 1.2 Regulation of testicular secretion 2. Endocrine function of ovary 2.1 Hormones secreted in ovary: estrogen and progestogen. Estrogen includes estradiol, estrone and estriol. 2.2 Functions of estrogen (1)Induces development of female accessory reproductive organs. (2) Induce and maintain secondary sex characters (3) Induce libido and sex behavior (4)Stimulates breast development (5)Induce porliferation of oviduct mucous membrane; Stimulate constriction of oviduct smooth muscle (6) Increased reabsorption of H2O, Na+, and Ca2+ in kidney. 2.3 Functions of progestogen (1) Effects on uterus: Promoting secretary changes in the uterine endometrium; Decrease the sensibility of uterus muscle to stimulatus. (2)Effects on breast: promoting developing of breast (3) Inhibit ovulation (4) Induce maternal behavior (5)Effect on body temperature