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1 Chapter 18 The Endocrine System Endocrine and nervous systems work together Endocrine and nervous systems work together Endocrine system Endocrine system.

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Presentation on theme: "1 Chapter 18 The Endocrine System Endocrine and nervous systems work together Endocrine and nervous systems work together Endocrine system Endocrine system."— Presentation transcript:

1 1 Chapter 18 The Endocrine System Endocrine and nervous systems work together Endocrine and nervous systems work together Endocrine system Endocrine system hormones released into the bloodstream travel throughout the body hormones released into the bloodstream travel throughout the body results may take hours, but last longer results may take hours, but last longer Nervous system Nervous system certain parts release hormones into blood certain parts release hormones into blood rest releases neurotransmitters excite or inhibit nerve, muscle & gland cells rest releases neurotransmitters excite or inhibit nerve, muscle & gland cells results in milliseconds, brief duration of effects results in milliseconds, brief duration of effects

2 2 General Functions of Hormones Help regulate: Help regulate: extracellular fluid extracellular fluid metabolism metabolism biological clock biological clock contraction of cardiac & smooth muscle contraction of cardiac & smooth muscle glandular secretion glandular secretion some immune functions some immune functions Growth & development Growth & development Reproduction Reproduction

3 3 Endocrine Glands Defined Exocrine glands Exocrine glands secrete products into ducts which empty into body cavities or body surface secrete products into ducts which empty into body cavities or body surface sweat, oil, mucous, & digestive glands sweat, oil, mucous, & digestive glands Endocrine glands Endocrine glands secrete products (hormones) into bloodstream secrete products (hormones) into bloodstream pituitary, thyroid, parathyroid, adrenal, pineal pituitary, thyroid, parathyroid, adrenal, pineal other organs secrete hormones as a 2nd function other organs secrete hormones as a 2nd function hypothalamus, thymus, pancreas,ovaries,testes, kidneys, stomach, liver, small intestine, skin, heart & placenta hypothalamus, thymus, pancreas,ovaries,testes, kidneys, stomach, liver, small intestine, skin, heart & placenta

4 4 Hormone Receptors Hormones only affect target cells with specific membrane proteins called receptors Hormones only affect target cells with specific membrane proteins called receptors

5 5 Role of Hormone Receptors Constantly being synthesized & broken down Constantly being synthesized & broken down A range of ,000 receptors / target cell A range of ,000 receptors / target cell Down-regulation Down-regulation excess hormone, produces a decrease in number of receptors excess hormone, produces a decrease in number of receptors receptors undergo endocytosis and are degraded receptors undergo endocytosis and are degraded decreases sensitivity of target cell to hormone decreases sensitivity of target cell to hormone Up-regulation Up-regulation deficiency of hormone, produces an increase in the number of receptors deficiency of hormone, produces an increase in the number of receptors target tissue more sensitive to the hormone target tissue more sensitive to the hormone

6 6 Blocking Hormone Receptors Synthetic hormones that block receptors for naturally occurring hormones Synthetic hormones that block receptors for naturally occurring hormones RU486 (mifepristone) binds to the receptors for progesterone preventing it from maintaining the uterus in a pregnant woman RU486 (mifepristone) binds to the receptors for progesterone preventing it from maintaining the uterus in a pregnant woman used to induce abortion used to induce abortion brings on menstrual cycle brings on menstrual cycle Hormone is prevented from interacting with its receptors and can not perform its normal functions Hormone is prevented from interacting with its receptors and can not perform its normal functions

7 7 Circulating & Local Hormones Circulating hormones Circulating hormones act on distant targets act on distant targets travel in blood travel in blood Local hormones Local hormones paracrines act on neighboring cells paracrines act on neighboring cells autocrines act on same cell that secreted them autocrines act on same cell that secreted them

8 8 Lipid-soluble Hormones Steroids Steroids lipids derived from cholesterol on SER lipids derived from cholesterol on SER different functional groups attached to core of structure provide uniqueness different functional groups attached to core of structure provide uniqueness Thyroid hormones Thyroid hormones tyrosine ring plus attached iodines are lipid-soluble tyrosine ring plus attached iodines are lipid-soluble Nitric oxide is gas Nitric oxide is gas

9 9 Water-soluble Hormones Amine, peptide and protein hormones Amine, peptide and protein hormones modified amino acids or amino acids put together modified amino acids or amino acids put together serotonin, melatonin, histamine, epinephrine serotonin, melatonin, histamine, epinephrine some glycoproteins some glycoproteins Eicosanoids Eicosanoids prostaglandins prostaglandins

10 10 Hormone Transport in Blood Protein hormones circulate in free form in blood Protein hormones circulate in free form in blood Steroid (lipid) & thyroid hormones must attach to transport proteins synthesized by liver Steroid (lipid) & thyroid hormones must attach to transport proteins synthesized by liver

11 11 General Mechanisms of Hormone Action Hormone binds to cell surface or receptor inside target cell Hormone binds to cell surface or receptor inside target cell Cell may then Cell may then synthesize new molecules synthesize new molecules change permeability of membrane change permeability of membrane alter rates of reactions alter rates of reactions Each target cell responds to hormone differently Each target cell responds to hormone differently liver cells---insulin stimulates glycogen synthesis liver cells---insulin stimulates glycogen synthesis adipose---insulin stimulates triglyceride synthesis adipose---insulin stimulates triglyceride synthesis

12 12 Action of Lipid-Soluble Hormones Hormone diffuses through phospholipid bilayer & into cell Hormone diffuses through phospholipid bilayer & into cell Binds to receptor turning on/off specific genes Binds to receptor turning on/off specific genes New mRNA is formed & directs synthesis of new proteins New mRNA is formed & directs synthesis of new proteins New protein alters cell’s activity New protein alters cell’s activity

13 13 Action of Water-Soluble Hormones Can not diffuse through plasma membrane Can not diffuse through plasma membrane Hormone receptors are integral membrane proteins Hormone receptors are integral membrane proteins act as first messenger act as first messenger

14 14 Amplification of Hormone Effects Single molecule of hormone binds to receptor Single molecule of hormone binds to receptor One molecule of epinephrine may result in breakdown of millions of glycogen molecules into glucose molecules One molecule of epinephrine may result in breakdown of millions of glycogen molecules into glucose molecules

15 15 Hormonal Interactions Permissive effect Permissive effect a second hormone, strengthens the effects of the first a second hormone, strengthens the effects of the first thyroid strengthens epinephrine’s effect upon lipolysis thyroid strengthens epinephrine’s effect upon lipolysis Synergistic effect Synergistic effect two hormones acting together for greater effect two hormones acting together for greater effect estrogen & LH are both needed for oocyte production estrogen & LH are both needed for oocyte production Antagonistic effects Antagonistic effects two hormones with opposite effects two hormones with opposite effects insulin promotes glycogen formation & glucagon stimulates glycogen breakdown insulin promotes glycogen formation & glucagon stimulates glycogen breakdown

16 16 Control of Hormone Secretion Regulated by signals from nervous system, chemical changes in the blood or by other hormones Regulated by signals from nervous system, chemical changes in the blood or by other hormones Negative feedback control (most common) Negative feedback control (most common) decrease/increase in blood level is reversed decrease/increase in blood level is reversed Positive feedback control Positive feedback control the change produced by the hormone causes more hormone to be released the change produced by the hormone causes more hormone to be released Disorders involve either hyposecretion or hypersecretion of a hormone Disorders involve either hyposecretion or hypersecretion of a hormone

17 17 Negative Feedback Systems Decrease in blood levels Decrease in blood levels Receptors in hypothalamus & thyroid Receptors in hypothalamus & thyroid Cells activated to secrete more TSH or more T3 & T4 Cells activated to secrete more TSH or more T3 & T4 Blood levels increase Blood levels increase

18 18 Positive Feedback Oxytocin stimulates uterine contractions Oxytocin stimulates uterine contractions Uterine contractions stimulate oxytocin release Uterine contractions stimulate oxytocin release

19 19 Hypothalamus and Pituitary Gland Both are master endocrine glands since their hormones control other endocrine glands Both are master endocrine glands since their hormones control other endocrine glands Hypothalamus is a section of brain above where pituitary gland is suspended from stalk Hypothalamus is a section of brain above where pituitary gland is suspended from stalk Hypothalamus receives input from cortex, thalamus, limbic system & internal organs Hypothalamus receives input from cortex, thalamus, limbic system & internal organs Hypothalamus controls pituitary gland with 9 different releasing & inhibiting hormones Hypothalamus controls pituitary gland with 9 different releasing & inhibiting hormones

20 20 Pea-shaped, 1/2 inch gland found in sella turcica of sphenoid Pea-shaped, 1/2 inch gland found in sella turcica of sphenoid Anterior lobe = 75% Posterior lobe = 25% Anterior lobe = 75% Posterior lobe = 25% ends of axons of 10,000 neurons found in hypothalamus ends of axons of 10,000 neurons found in hypothalamus Anatomy of Pituitary Gland

21 21 Flow of Blood to Anterior Pituitary Controlling hormones enter blood Controlling hormones enter blood Travel through portal veins Travel through portal veins Enter anterior pituitary at capillaries Enter anterior pituitary at capillaries

22 22 Human Growth Hormone Produced by somatotrophs Produced by somatotrophs Within target cells increases synthesis of insulinlike growth factors that act locally or enter bloodstream Within target cells increases synthesis of insulinlike growth factors that act locally or enter bloodstream common target cells are liver, skeletal muscle, cartilage and bone common target cells are liver, skeletal muscle, cartilage and bone increases cell growth & cell division by increasing their uptake of amino acids & synthesis of proteins increases cell growth & cell division by increasing their uptake of amino acids & synthesis of proteins stimulate lipolysis in adipose so fatty acids used for ATP stimulate lipolysis in adipose so fatty acids used for ATP retard use of glucose for ATP production so blood glucose levels remain high enough to supply brain retard use of glucose for ATP production so blood glucose levels remain high enough to supply brain

23 23 Regulation of hGH Low blood sugar stimulates release of GNRH from hypothalamus Low blood sugar stimulates release of GNRH from hypothalamus anterior pituitary releases more hGH, more glycogen broken down into glucose by liver cells anterior pituitary releases more hGH, more glycogen broken down into glucose by liver cells High blood sugar stimulates release of GHIH from hypothalamus High blood sugar stimulates release of GHIH from hypothalamus less hGH from anterior pituitary, glycogen does not breakdown into glucose less hGH from anterior pituitary, glycogen does not breakdown into glucose

24 24 Diabetogenic Effect of Human Growth Hormone Excess of growth hormone Excess of growth hormone raises blood glucose concentration raises blood glucose concentration pancreas releases insulin continually pancreas releases insulin continually beta-cell burnout beta-cell burnout Diabetogenic effect Diabetogenic effect causes diabetes mellitis if no insulin activity can occur eventually causes diabetes mellitis if no insulin activity can occur eventually

25 25 Thyroid Stimulating Hormone (TSH) Hypothalamus regulates thyrotroph cells Hypothalamus regulates thyrotroph cells Thyrotroph cells produce TSH Thyrotroph cells produce TSH TSH stimulates the synthesis & secretion of T3 and T4 TSH stimulates the synthesis & secretion of T3 and T4 Metabolic rate stimulated Metabolic rate stimulated

26 26 Follicle Stimulating Hormone (FSH) Releasing hormone from hypothalamus controls gonadotrophs Releasing hormone from hypothalamus controls gonadotrophs Gonadotrophs release follicle stimulating hormone Gonadotrophs release follicle stimulating hormone FSH functions FSH functions initiates the formation of follicles within the ovary initiates the formation of follicles within the ovary stimulates follicle cells to secrete estrogen stimulates follicle cells to secrete estrogen stimulates sperm production in testes stimulates sperm production in testes

27 27 Luteinizing Hormone (LH) Releasing hormones from hypothalamus stimulate gonadotrophs Releasing hormones from hypothalamus stimulate gonadotrophs Gonadotrophs produce LH Gonadotrophs produce LH In females, LH stimulates In females, LH stimulates secretion of estrogen secretion of estrogen ovulation of 2nd oocyte from ovary ovulation of 2nd oocyte from ovary formation of corpus luteum formation of corpus luteum secretion of progesterone secretion of progesterone In males, stimulates interstitial cells to secrete testosterone In males, stimulates interstitial cells to secrete testosterone

28 28 Prolactin (PRL) Hypothalamus regulates lactotroph cells Hypothalamus regulates lactotroph cells Lactotrophs produce prolactin Lactotrophs produce prolactin Under right conditions, prolactin causes milk production Under right conditions, prolactin causes milk production Suckling reduces levels of hypothalamic inhibition and prolactin levels rise along with milk production Suckling reduces levels of hypothalamic inhibition and prolactin levels rise along with milk production Nursing ceases & milk production slows Nursing ceases & milk production slows

29 29 Adrenocorticotrophic Hormone Hypothalamus releasing hormones stimulate corticotrophs Hypothalamus releasing hormones stimulate corticotrophs Corticotrophs secrete ACTH & MSH Corticotrophs secrete ACTH & MSH ACTH stimulates cells of the adrenal cortex that produce glucocorticoids ACTH stimulates cells of the adrenal cortex that produce glucocorticoids

30 30 Melanocyte-Stimulating Hormone Secreted by corticotroph cells Secreted by corticotroph cells Releasing hormone from hypothalamus increases its release From the anterior pituitary Releasing hormone from hypothalamus increases its release From the anterior pituitary Function not certain in humans (increase skin pigmentation in frogs ) Function not certain in humans (increase skin pigmentation in frogs )

31 31 Posterior Pituitary Gland (Neurohypophysis) Does not synthesize hormones Does not synthesize hormones Consists of axon terminals of hypothalamic neurons Consists of axon terminals of hypothalamic neurons Neurons release two neurotransmitters that enter capillaries Neurons release two neurotransmitters that enter capillaries antidiuretic hormone antidiuretic hormone oxytocin oxytocin

32 32Oxytocin Two target tissues both involved in neuroendocrine reflexes Two target tissues both involved in neuroendocrine reflexes During delivery During delivery baby’s head stretches cervix baby’s head stretches cervix hormone release enhances uterine muscle contraction hormone release enhances uterine muscle contraction baby & placenta are delivered baby & placenta are delivered After delivery After delivery suckling & hearing baby’s cry stimulates milk ejection suckling & hearing baby’s cry stimulates milk ejection hormone causes muscle contraction & milk ejection hormone causes muscle contraction & milk ejection

33 33 Oxytocin during Labor Stimulation of uterus by baby Stimulation of uterus by baby Hormone release from posterior pituitary Hormone release from posterior pituitary Uterine smooth muscle contracts until birth of baby Uterine smooth muscle contracts until birth of baby Baby pushed into cervix, increase hormone release Baby pushed into cervix, increase hormone release More muscle contraction occurs More muscle contraction occurs When baby is born, positive feedback ceases When baby is born, positive feedback ceases

34 34 Antidiuretic Hormone (ADH) Known as vasopressin Known as vasopressin Functions Functions decrease urine production decrease urine production decrease sweating decrease sweating increase BP increase BP

35 35 Regulation of ADH Dehydration Dehydration ADH released ADH released Overhydration Overhydration ADH inhibited ADH inhibited

36 36 Thyroid Gland On each side of trachea is lobe of thyroid On each side of trachea is lobe of thyroid Weighs 1 oz & has rich blood supply Weighs 1 oz & has rich blood supply

37 37 Photomicrograph of Thyroid Gland

38 38 Actions of Thyroid Hormones T3 & T4 = thyroid hormones responsible for our metabolic rate, synthesis of protein, breakdown of fats, use of glucose for ATP production T3 & T4 = thyroid hormones responsible for our metabolic rate, synthesis of protein, breakdown of fats, use of glucose for ATP production Calcitonin = responsible for building of bone & stops reabsorption of bone (lower blood levels of Calcium) Calcitonin = responsible for building of bone & stops reabsorption of bone (lower blood levels of Calcium)

39 39 Control of T3 & T4 Secretion Negative feedback system Negative feedback system Low blood levels of hormones stimulate hypothalamus Low blood levels of hormones stimulate hypothalamus It stimulates pituitary to release TSH It stimulates pituitary to release TSH TSH stimulates gland to raise blood levels TSH stimulates gland to raise blood levels

40 40 Parathyroid Glands 4 pea-sized glands found on back of thyroid gland 4 pea-sized glands found on back of thyroid gland

41 41 Parathyroid Hormone Raise blood calcium levels Raise blood calcium levels increase activity of osteoclasts increase activity of osteoclasts increases reabsorption of Ca+2 by kidney increases reabsorption of Ca+2 by kidney promote formation of calcitriol (vitamin D3) by kidney which increases absorption of Ca+2 and Mg+2 by intestinal tract promote formation of calcitriol (vitamin D3) by kidney which increases absorption of Ca+2 and Mg+2 by intestinal tract Opposite function of calcitonin Opposite function of calcitonin

42 42 Regulation of Calcium Blood Levels High or low blood levels of Ca+2 stimulate the release of different hormones --- PTH or CT High or low blood levels of Ca+2 stimulate the release of different hormones --- PTH or CT

43 43 Adrenal Glands One on top of each kidney One on top of each kidney 3 x 3 x 1 cm in size and weighs 5 grams 3 x 3 x 1 cm in size and weighs 5 grams Cortex produces 3 different types of hormones from 3 zones of cortex Cortex produces 3 different types of hormones from 3 zones of cortex Medulla produces epinephrine & norepinephrine Medulla produces epinephrine & norepinephrine

44 44 Structure of Adrenal Gland Cortex derived from mesoderm Cortex derived from mesoderm Medulla derived from ectoderm Medulla derived from ectoderm

45 45 Regulation of Aldosterone

46 46 Glucocorticoids 95% of hormonal activity is due to cortisol 95% of hormonal activity is due to cortisol Functions = help regulate metabolism Functions = help regulate metabolism increase rate of protein catabolism & lipolysis increase rate of protein catabolism & lipolysis conversion of amino acids to glucose conversion of amino acids to glucose stimulate lipolysis stimulate lipolysis provide resistance to stress by making nutrients available for ATP production provide resistance to stress by making nutrients available for ATP production raise BP by vasoconstriction raise BP by vasoconstriction anti-inflammatory effects reduced (skin cream) anti-inflammatory effects reduced (skin cream) reduce release of histamine from mast cells reduce release of histamine from mast cells decrease capillary permeability decrease capillary permeability depress phagocytosis depress phagocytosis

47 47 Regulation of Glucocorticoids Negative feedback Negative feedback

48 48 Androgens from Zona Reticularis Small amount of male hormone produced Small amount of male hormone produced insignificant in males insignificant in males may contribute to sex drive in females may contribute to sex drive in females is converted to estrogen in postmenopausal females is converted to estrogen in postmenopausal females

49 49 Adrenal Medulla Chromaffin cells receive direct innervation from sympathetic nervous system Chromaffin cells receive direct innervation from sympathetic nervous system develop from same tissue as postganglionic neurons develop from same tissue as postganglionic neurons Produce epinephrine & norepinephrine Produce epinephrine & norepinephrine Hormones are sympathomimetic Hormones are sympathomimetic effects mimic those of sympathetic NS effects mimic those of sympathetic NS cause fight-flight behavior cause fight-flight behavior Acetylcholine increase hormone secretion by adrenal medulla Acetylcholine increase hormone secretion by adrenal medulla

50 50 Anatomy of Pancreas Organ (5 inches) consists of head, body & tail Organ (5 inches) consists of head, body & tail Cells (99%) in acini produce digestive enzymes Cells (99%) in acini produce digestive enzymes Endocrine cells in pancreatic islets produce hormones Endocrine cells in pancreatic islets produce hormones

51 51 Cell Types in the Pancreatic Islets Alpha cells (20%) produce glucagon Alpha cells (20%) produce glucagon Beta cells (70%) produce insulin Beta cells (70%) produce insulin Delta cells (5%) produce somatostatin Delta cells (5%) produce somatostatin F cells produce pancreatic polypeptide F cells produce pancreatic polypeptide

52 52 Regulation of Glucagon & Insulin Secretion Low blood glucose stimulates release of glucagon Low blood glucose stimulates release of glucagon High blood glucose stimulates secretion of insulin High blood glucose stimulates secretion of insulin

53 53 Ovaries and Testes Ovaries Ovaries estrogen, progesterone, relaxin & inhibin estrogen, progesterone, relaxin & inhibin regulate reproductive cycle, maintain pregnancy & prepare mammary glands for lactation regulate reproductive cycle, maintain pregnancy & prepare mammary glands for lactation Testes Testes produce testosterone produce testosterone regulate sperm production & 2nd sexual characteristics regulate sperm production & 2nd sexual characteristics

54 54 Pineal Gland Small gland attached to 3rd ventricle of brain Small gland attached to 3rd ventricle of brain Melatonin responsible for setting of biological clock Melatonin responsible for setting of biological clock Jet lag & SAD treatment is bright light Jet lag & SAD treatment is bright light

55 55 Effect of Light on Pineal Gland Melatonin secretion producing sleepiness occurs during darkness due to lack of stimulation from sympathetic ganglion Melatonin secretion producing sleepiness occurs during darkness due to lack of stimulation from sympathetic ganglion

56 56 Seasonal Affective Disorder and Jet Lag Depression that occurs during winter months when day length is short Depression that occurs during winter months when day length is short Due to overproduction of melatonin Due to overproduction of melatonin Therapy Therapy exposure to several hours per day of artificial light as bright as sunlight exposure to several hours per day of artificial light as bright as sunlight speeds recovery from jet lag speeds recovery from jet lag

57 57 Thymus Gland Important role in maturation of T cells Important role in maturation of T cells Hormones produced by gland promote the proliferation & maturation of T cells Hormones produced by gland promote the proliferation & maturation of T cells thymosin thymosin thymic humoral factor thymic humoral factor thymic factor thymic factor thymopoietin thymopoietin

58 58 Miscellaneous Hormones Eicosanoids Local hormones released by all body cells Local hormones released by all body cells Leukotrienes influence WBCs & inflammation Leukotrienes influence WBCs & inflammation Prostaglandins alter Prostaglandins alter smooth muscle contraction, glandular secretion, blood flow, platelet function, nerve transmission, metabolism etc. smooth muscle contraction, glandular secretion, blood flow, platelet function, nerve transmission, metabolism etc. Ibuprofen & other nonsteroidal anti-inflammatory drugs treat pain, fever & inflammation by inhibiting prostaglandin synthesis Ibuprofen & other nonsteroidal anti-inflammatory drugs treat pain, fever & inflammation by inhibiting prostaglandin synthesis

59 59 Nonsteroidal Anti-inflammatory Drugs Answer to how aspirin or ibuprofen works was discovered in 1971 Answer to how aspirin or ibuprofen works was discovered in 1971 inhibit a key enzyme in prostaglandin synthesis without affecting the synthesis of leukotrienes inhibit a key enzyme in prostaglandin synthesis without affecting the synthesis of leukotrienes Treat a variety of inflammatory disorders Treat a variety of inflammatory disorders rheumatoid arthritis rheumatoid arthritis Usefulness of aspirin to treat fever & pain implies prostaglandins are responsible for those symptoms Usefulness of aspirin to treat fever & pain implies prostaglandins are responsible for those symptoms

60 60 Growth Factors Substances with mitogenic qualities Substances with mitogenic qualities cause cell growth from cell division cause cell growth from cell division Many act locally as autocrines or paracrines Many act locally as autocrines or paracrines Selected list of growth factors (Table 18.12) Selected list of growth factors (Table 18.12) epidermal growth factor epidermal growth factor platelet-derived growth factor platelet-derived growth factor fibroblast growth factor fibroblast growth factor nerve growth factor nerve growth factor tumor angiogenesis factors tumor angiogenesis factors transforming growth factors transforming growth factors

61 61 Stress & General Adaptation Syndrome Stress response is set of bodily changes called general adaptation syndrome (GAS) Stress response is set of bodily changes called general adaptation syndrome (GAS) Any stimulus that produces a stress response is called a stressor Any stimulus that produces a stress response is called a stressor Stress resets the body to meet an emergency Stress resets the body to meet an emergency eustress is productive stress & helps us prepare for certain challenges eustress is productive stress & helps us prepare for certain challenges distress type levels of stress are harmful distress type levels of stress are harmful lower our resistance to infection lower our resistance to infection

62 62 Alarm Reaction (Fight-or-Flight) Initiated by hypothalamic stimulation of sympathetic portion of the ANS & adrenal medulla Initiated by hypothalamic stimulation of sympathetic portion of the ANS & adrenal medulla Dog attack Dog attack increases circulation increases circulation promotes ATP synthesis promotes ATP synthesis nonessential body functions are inhibited nonessential body functions are inhibited digestive, urinary & reproductive digestive, urinary & reproductive

63 63 Resistance Reaction Initiated by hypothalamic releasing hormones (long-term reaction to stress) Initiated by hypothalamic releasing hormones (long-term reaction to stress) corticotropin, growth hormone & thyrotropin releasing hormones corticotropin, growth hormone & thyrotropin releasing hormones Results Results increased secretion of aldosterone acts to conserve Na+ (increases blood pressure) and eliminate H+ increased secretion of aldosterone acts to conserve Na+ (increases blood pressure) and eliminate H+ increased secretion of cortisol so protein catabolism is increased & other sources of glucose are found increased secretion of cortisol so protein catabolism is increased & other sources of glucose are found increase thyroid hormone to increase metabolism increase thyroid hormone to increase metabolism Allow body to continue to fight a stressor Allow body to continue to fight a stressor

64 64 Exhaustion Resources of the body have become depleted Resources of the body have become depleted Resistance stage can not be maintained Resistance stage can not be maintained Prolonged exposure to resistance reaction hormones Prolonged exposure to resistance reaction hormones wasting of muscle wasting of muscle suppression of immune system suppression of immune system ulceration of the GI tract ulceration of the GI tract failure of the pancreatic beta cells failure of the pancreatic beta cells

65 65 Stress and Disease Stress can lead to disease by inhibiting the immune system Stress can lead to disease by inhibiting the immune system hypertension, asthma, migraine, gastritis, colitis, and depression hypertension, asthma, migraine, gastritis, colitis, and depression Interleukin - 1 is secreted by macrophages Interleukin - 1 is secreted by macrophages link between stress and immunity link between stress and immunity stimulates production of immune substances stimulates production of immune substances feedback control since immune substance suppress the formation of interleukin-1 feedback control since immune substance suppress the formation of interleukin-1

66 66 Aging and the Endocrine System Production of human growth hormone decreases Production of human growth hormone decreases muscle atrophy muscle atrophy Production of TSH increase with age to try and stimulate thyroid Production of TSH increase with age to try and stimulate thyroid decrease in metabolic rate, increase in body fat & hypothyroidism decrease in metabolic rate, increase in body fat & hypothyroidism Thymus after puberty is replaced with adipose Thymus after puberty is replaced with adipose Adrenal glands produce less cortisol & aldosterone Adrenal glands produce less cortisol & aldosterone Receptor sensitivity to glucose declines Receptor sensitivity to glucose declines Ovaries no longer respond to gonadotropins Ovaries no longer respond to gonadotropins decreased output of estrogen (osteoporosis & atherosclerosis) decreased output of estrogen (osteoporosis & atherosclerosis)

67 67 Pituitary Gland Disorders Hyposecretion during childhood = pituitary dwarfism (proportional, childlike body) Hyposecretion during childhood = pituitary dwarfism (proportional, childlike body) Hypersecretion during childhood = giantism Hypersecretion during childhood = giantism very tall, normal proportions very tall, normal proportions Hypersecretion as adult = acromegaly Hypersecretion as adult = acromegaly growth of hands, feet, facial features & thickening of skin growth of hands, feet, facial features & thickening of skin

68 68 Thyroid Gland Disorders Hyposecretion during infancy results in dwarfism & retardation called cretinism Hyposecretion during infancy results in dwarfism & retardation called cretinism Hypothyroidism in adult produces sensitivity to cold, low body temp. weight gain & mental dullness Hypothyroidism in adult produces sensitivity to cold, low body temp. weight gain & mental dullness Hyperthyroidism (Grave’s disease) Hyperthyroidism (Grave’s disease) weight loss, nervousness, tremor & exophthalmos (edema behind eyes) weight loss, nervousness, tremor & exophthalmos (edema behind eyes) Goiter = enlarged thyroid (dietary) Goiter = enlarged thyroid (dietary)

69 69 Cushing’s Syndrome Hypersecretion of glucocorticoids Hypersecretion of glucocorticoids Redistribution of fat, spindly arms & legs due to muscle loss Redistribution of fat, spindly arms & legs due to muscle loss Wound healing is poor, bruise easily Wound healing is poor, bruise easily

70 70 Addison’s disease Hypersecretion of glucocorticoids Hypersecretion of glucocorticoids hypoglycemia, muscle weakness, low BP, dehydration due to decreased Na+ in blood hypoglycemia, muscle weakness, low BP, dehydration due to decreased Na+ in blood mimics skin darkening effects of MSH mimics skin darkening effects of MSH potential cardiac arrest potential cardiac arrest

71 71 Diabetes Mellitus & Hyperinsulinism Diabetes mellitus marked by hyperglycemia Diabetes mellitus marked by hyperglycemia excessive urine production (polyuria) excessive urine production (polyuria) excessive thirst (polydipsia) excessive thirst (polydipsia) excessive eating (polyphagia) excessive eating (polyphagia) Type I----deficiency of insulin (under 20) Type I----deficiency of insulin (under 20) Type II---adult onset Type II---adult onset drug stimulates secretion of insulin by beta cells drug stimulates secretion of insulin by beta cells cells may be less sensitive to hormone cells may be less sensitive to hormone


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