1 ENDOCRINE SYSTEM

2 TWO GREAT CONTROLLING SYSTEMSNervous System Endocrine System

3 1) NERVOUS SYSTEM Regulates activity via action potential impulses ~ AP’s Impulses carried by specific sensory or motor neurons Uses “synaptic communication” to carry message Targets specific cells ~ for specific response Response is immediate & usually short lasting

4 2) ENDOCRINE SYSTEM Controls cell activity by secreting hormones ~ EXCITE Hormones = “Chemical Messengers” Secreted into blood & transported throughout body Generalized Widespread Response ~ Adrenalin or GH Targeted specific cells: TSH or FSH Diverse or very specific effects: Insulin ~ specific Adrenalin ~ diverse Response on target cells is delayed ~ due to circulation Delayed, prolonged or continuous response

5 ENDOCRINE SYSTEM ~ Controlling SpectrumMAJOR processes controlled by hormone release Reproduction Testosterone Estrogen Follicle Stimulating Hormone Leutenizing Hormone Oxytocin ~ “Post Pit”

6 Growth & Development Growth Hormone & Thyroid Hormone Body Defense Mechanisms Corticosteroids ~ Cortisone ~ Anti-inflammatory Anti-Stress Corticosteroids ~ Gluconeogenesis

7 Electrolyte, Water & Nutrient BalanceAldosterone ~ Na+ retention ~ water retention Anti-Diuretic Hormone ~ ADH Cell Metabolism & Energy Regulation Insulin & Thyroid Hormone Digestive Processes

8 TWO GLANDULAR SYSTEMS OF BODY1. EXOCRINE GLANDS ~ Merocrine Apocrine Holocrine ~ < PUREST MESSY > Secreted onto body surfaces ~ via ducts Secretions are non-hormonal Secreted & ACT LOCALLY in a target area only DO NOT secrete into blood or lymphatics Can be large in size or extensive in numbers ~ millions

9 Examples of Exocrine Glands SecreteMucous Glands Mucous Sudoriferous Glands Sweat Sebaceous or Oil Glands Sebum Salivary Glands Saliva Mammary Glands Milk Liver Bile Enteric Glands Digestion Reproductive Glands Several Pancreas ~ Both Exocrine & Endocrine

10 ENDOCRINE GLANDS “Ductless Glands” ~ produce hormones ~ NO DUCTSSecrete hormones most directly into blood Surrounded by many capillaries ~ allows secretion into blood Hormones travel through body ~ act on specific target organs Can have a generalized effect or specific target effect Effects can be short, prolonged or continuous lasting Small Glands ~ very localized, & few in numbers ~ 12 groups

11 ENDOCRINE GLANDS Pituitary Gland Heart Pineal Gland Small IntestinesThyroid Gland Kidney Parathyroid Gland Pancreas Thymus Gland Gonads (ovaries & testes ) Adrenal Gland Hypothalamus Other Specialized Cells can produce hormones Adipose Tissue Tumors or cancer cells

12 CHEMISTRY OF HORMONES Hormones ~ “chemical messengers” ~ “First Messengers” Control other parts of body from where secreted “Endocrine Communication” ~ NOT NEURAL MOST Secreted into blood & circulatory system Regulate functions of other cells somewhere else

13 Major Hormone Classifications1. Amino Acid Hormones ~ MOST COMMON Most hormones are globular proteins or peptides

14 2. Lipid Hormones Steroid Hormones ~ from cholesterolGonadal hormones ~ estrogen, testosterone Adrenalcorticoids hormones ~ corticosteroids Eicosanoids (eye cos an oids) Increase inflammation & cause swelling NON-CIRCULATING hormones ~ act locally only Released from most cell membranes & have a highly localized response Prostaglandins ~ most common

15 MECHANISM OF HORMONE ACTIONHormones effect target cells ~ alter cell activity Increase or decrease types & rates of cellular processes Up-Regulation ~ increased sensitivity to hormone effects Down-Regulation ~ less sensitive to hormone effects Activity is very specific on a specific target cell EG: Epinephrine causes blood vessel walls to contract It will also cause an increase in heart rate

16 HORMONE EFFECTS ON TARGET CELLS1. Change plasma membrane permeability 2. Change electrical charge of plasma membranes 3. Stimulate secretory activity of cells 4. Stimulate mitosis & cell division 5. Stimulate Enzyme Activation or Deactivation ~ MOST COMMON Forms NEW proteins within cells Amino Acid Hormones ~ cAMP Second Messenger 6. Stimulate Gene Activation ~ COMMON Lipid/Steroid Hormones ~ Form New Proteins

17 EXAMPLES ~ MECHANISMS OF HORMONE ACTIONAMINO-ACID HORMONES (“PEPTIDES”) ~ MOST COMMON Utilizes a Second Messenger System Hormone ~ is the first messenger Hormone CANNOT penetrate cell membrane ~ to big Binds to “hormone receptor” site on target cell Receptor binding ---> activates a “G-protein” ---> which activates an effector enzyme Effector Enzyme = Adenylate cyclase Adenylate cyclase generates Second Messenger ~ cAMP cAMP activates protein kinase - - -> form NEW PROTEINS inside cell MANY reactions follow & cause specific cell activities

18 LIPID ~ STEROID HORMONES “from CHOLESTEROL”Utilizes: Gene Activation ~ NO 2nd messenger system Smaller & lipid soluble ~ can penetrate cell membrane Once inside target cells ~ gene activation occurs DNA is “transcribed” to messenger RNA ~ mRNA mRNA ~ stimulates production of NEW proteins

19 HORMONE TARGET CELL ACTIVATION & SPECIFICITYMajor hormones circulate in blood to all tissue Specific hormones effect only specific tissue cells

20 Hormone Receptors ~ located on or in cellsTarget Cells have specific hormone receptors on cell membranes or inside target tissue that bind hormones Receptor Binding is required for activity SOME receptors are found only on/in SPECIFIC CELLS Example: ACTH stimulates only the adrenal cortex SOME receptors are found on/in MOST BODY CELLS Example: Thyroxine stimulates most cells Insulin affects all cells of body

21 Target Cell Activation RequirementsAdequate Hormone Blood Levels Specific Receptor Binding Sites Adequate Number of Receptors on or within cells Specific Bonding Affinity between Hormone & Receptor Any +/- Changes in any of the above results in: Endocrine Dysfunction  Up Regulation OR  Down Regulation

22 ENDOCRINE DYSFUNCTIONUp-Regulation ~ Sensitization ~ Stimulation Occurs when target cells form MORE receptors in response to hormone presence Down-Regulation ~ Desensitization ~ Inhibition Occurs when prolonged exposure to high hormone levels causes LOSS of receptors Desensitizes target cells resulting in lower activity Hormones also STIMULATE or INHIBIT other hormones EG: Estrogen stimulates Progesterone release Progesterone antagonizes Estrogen action

23 DURATION OF HORMONAL ACTIVITY ~ “Half-Life”Dependent on circulating blood levels of Hormone 1) Rate of Release into the blood 2) Speed of Inactivation & Removal from the body Methods of Inactivation ~ Removal from body 1) Degradation by enzymes in target cells 2) Removed from blood via Kidney and Liver 3) Excreted in Urine or Feces

24 HALF-LIFE Time required to reduce blood concentrations by 50%Ranges from seconds to minutes to hours or longer What is the Half-Life? If blood concentration is 20 units & units remain after 7 minutes units remain after 14 minutes = HALF-LIFE units remain after 21 minutes

25 Endocrine Reflexes ~ CONTROL HORMONE RELEASEBlood levels are precisely controlled for optimal effects 1) POSITIVE FEEDBACK MECHANISM As hormone is released, target organ stimulates the release of more hormone more more more EG: Oxytocin ~ Childbirth 2) NEGATIVE FEEDBACK MECHANISM ~ MOST COMMON As blood hormone levels rise, target organs inhibit further hormone release ~ on off on off EG: thermostat in a house EG: High blood sugar ---> insulin release ---> ---> glucose uptake into cells ---> lower blood sugar

26 TYPES OF ENDOCRINE GLAND RELEASE STIMULIEndocrine Gland Reflexes Stimulate glands to produce & release hormones 1) Humoral Stimuli ~ ions & chemicals 2) Neural Stimuli ~ nerve impulses 3) Hormonal Stimuli ~ other hormones

27 HUMORAL STIMULI Hormones secreted in direct response to changing blood levels of certain IONS & CHEMICALS Examples: Low blood Ca+ ---> parathyroid gland to secrete parathyroid hormone (PTH) ---> higher blood Ca+ ---> reduced secretion of PTH High blood sugar ---> pancreas to secrete insulin ---> lowering of blood sugar

28 NEURAL STIMULI Nerve IMPULSES (AP’s) stimulate hormone releaseEG: Stress ---> Sympathetic NS activation ---> adrenal medulla secretes catecholamines Adrenalin ~ norepinephrine & epinephrine

29 HORMONAL “TROPIC” STIMULI ~ COMMONOccurs when an endocrine gland releases hormones that stimulate OTHER endocrine glands to release hormones Hypothalamus ~ Highest level of endocrine control Integrates activities of endocrine & nervous system Produces Hormones that regulates Pituitary Gland Pituitary produces other hormones that regulate OTHER glands Hypothalamic-Pituitary -Target Endocrine Gland Feedback Loop

30 SEVERAL Hypothalamus “Regulating” HormonesThyrotropic Releasing Hormone (TRH) Stimulates release of TSH from Ant. Pituitary TSH stimulatesThyroid Hormone from Thyroid Corticotropin Releasing Hormone (CRH) Stimulates release of ACTH from Ant. Pituitary Stimulates Adrenal Hormones from Adrenals Gonadotropin Releasing Hormone (GnRH) Stimulates release of FSH & LH from Ant. Pit. Stimulates Testosterone, Estrogen & Progesterone from Gonad

32 HYPOTHALAMUS Located above the brain stem ~ in diencephalon Controls Autonomic Nervous System 1. Controls emotion ~ rage, fear, anger, pleasure 2. Body temperature regulation 3. Food intake regulation ~ appetite 4. Water balance & thirst regulation Controls Endocrine System Produces Hormones that “regulate” the Anterior Pituitary Produces two hormones released by the Posterior Pituitary ADH Oxytocin

33 HYPOTHALAMUS Produces “Releasing & Inhibiting” Regulating Hormones Carried via “Hypophyseal Portal System” to Ant. Pit. Vascular connection ~ hypothalamus & Ant. Pit “Releasing” Hormones Stimulate secretion of Anterior Pituitary Hormones “Inhibiting” Hormones Inhibit release of Anterior Pituitary Hormones

34 Produces 2 “Neuro-Hormones” for Posterior PituitaryParaventricular Nucleus ----> Oxytocin Supraoptic Nucleus ----> Anti-diuretic Hormone ~ ADH Carried via “Hypothalamic-Hypophyseal Tract” by axons to posterior pituitary Neuro-Hormones are secreted by Posterior Pituitary

35 “Hypophyseal Portal System”Vascular connection ~ hypothalamus & anterior pituitary “Hypothalamic-Hypophyseal Tract” Neural connection ~ hypothalamus & posterior pituitary

36 12 MAJOR ENDOCRINE ORGANSPITUITARY GLAND Also called the “Hypophysis” ~ “Master Gland of Body” Protected by sella turcica of the sphenoid bone At the base of the brain ~ not a part of nervous system Infundibulum ~ “stalk” ~ connects pituitary to hypothalamus Two lobes: Anterior Pituitary ~ “adenohypophysis” Posterior Pituitary ~ “neurohypophysis”

39 ANTERIOR PITUITARY ~ “Master Endocrine Gland”Anterior Lobe ~ “Adenohypophysis” Controlled by the hypothalamus via regulating hormones Hypophyseal Portal System Fenestrated Capillaries ~ vascular bed connections Allows hypothalamic hormones to circulate through the anterior pituitary Regulating Hormones ~ regulate the secretions of other hormones from anterior pituitary gland

40 Secretes 6 major hormones ~ ALL ARE PROTEINSInstantaneous Response ~ NO storage in Anterior Pit. Tropic Hormones: Hormonal Stimuli Regulate the secretory action of OTHER endocrine glands to release other hormones TSH Thyroid Stimulating Hormone ACTH Adrenal Corticotropic Hormone FSH Follicle Stimulating Hormone LH Leutenizing Hormone

41 Non-tropic Hormones: Effects NON-ENDOCRINE glandsGH Growth Hormone PRL Prolactin

42 ANTERIOR PITUITARY - “TROPIC” HORMONESTHYROID STIMULATING HORMONE ~ TSH TRH ~ Thyrotropin Releasing Hormone - Hypothalamus Stimulates release of TSH from Anterior Pituitary TSH (tropic) ~ stimulates Thyroid Gland to secrete Thyroid Hormone

43 Negative Feedback “Shut Off” MechanismRising blood levels of TH “shuts off” the Hypothalamus & Anterior Pituitary to block further TSH release Factors releasing TRH from Hypothalamus 1. Increased Energy Demands 2. Need to raise metabolic rate 3. Need to produce & release heat EG: Pregnancy Cold temperatures Exercise Fever

44 ADRENOCORTICOTROPIC HORMONE ~ ACTH CRH ~ Corticotropin Releasing Hormone - Hypothalamus Stimulates release of ACTH from Anterior Pituitary ACTH tropic action: stimulates the adrenal cortex to release several other hormones: 1) Gluco-corticoids ~ corticosteroids ~ mostly 2) Gonado-corticoids ~ androgens ~ small amount 3) Mineralo-cortacoids ~ aldosterone

45 Negative Feedback “Shut Off” MechanismRising blood levels of “corticoids” cause Anterior Pituitary & Hypothalamus to block further CRH release Factors stimulating CRH release: fever hypoglycemia stress dehydration shock blood loss low blood pressure

46 GONADOTROPINS FSH ~ Follicle Stimulating Hormone LH ~ Leuteinizing Hormone GnRH ~ gonadotropin releasing hormone from Hypothalamus Stimulates release of FSH or LH from Anterior Pituitary

47 FSH and LH ~ action is tropicStimulate gonad activity ~ ovaries & testes ~ at puberty FSH ~ stimulates sperm & egg production LH ~ cause ovarian follicle maturation & ovulation ~ causes release of Gonadal Hormones Estrogen ~ Female ~ controls menstrual cycle Progesterone ~ Female ~ maintains pregnancy Testosterone ~ Male Testicular Hormone

48 Negative Feedback “Shut-Off” MechanismRising blood levels of gonad hormones causes the Hypothalamus to block GnRH release, & inhibits FSH & LH release from Anterior Pituitary

49 ANTERIOR PITUITARY - “NON-TROPIC” HORMONESGROWTH HORMONE ~ GH ~ “Somatotropin” “Anabolic Hormone” ~ stimulates most body cells to increase in size and divide GH targets bones & skeletal muscles Stimulates epiphyseal plate & long bone growth Increases skeletal muscle mass “Insulin-growth factor” ~ Somatomedins ~ enhance GH Protein produced in liver & muscle stimulate growth

50 GH Actions 1) Stimulates protein synthesis ~ anabolic ~ muscles2) Stimulates cartilage & bone development 3) Stimulates fats for energy ~ increases glucose 4) Converts glucose to glycogen stores for future 5) Causes a “diabetogenic” effect Causes glycogen breakdown & release of glucose into blood causing ↑ blood sugar

51 GROWTH HORMONE ~ GH ~ “Somatotropin”Secretion of GH ~ NOT a feedback mechanism GHRH – GH Releasing Hormone Hypothalamic hormone - stimulates release of GH GHIH – GH Inhibiting Hormone – Somatostatin Hypothalamic hormone - inhibits release of GH

52 PROLACTIN ~ PRL PRL has direct action on non-endocrine mammary cells; Stimulates milk production by breast (not release) PRL is controlled by Hypothalamus PRH ~ Prolactin “Releasing” Hormone = seratonin; Causes prolactin release from Ant. Pituitary PIH ~ Prolactin “Inhibiting” Hormone = dopamine; Prevents prolactin secretion from Ant. Pituitary

53 PRL Levels fluctuates in females with ESTROGENLow Estrogen stimulates PIH ---> LESS Prolactin High Estrogen levels stimulates PRH ---> MORE PRL Menstruation ~ HIGH Estrogen ---> PRH ---> MORE PRL Breast swelling & tenderness ~ temporary Generally NO milk production Pregnancy ~ cause HIGH levels of PRH near term Infant Suckling ~ stimulates PRH ---> MORE PRL PRL Hyper-Secretion ~ occurs in nursing mothers PRL Hypo-Secretion – only occurs in heavy nursers

54 POSTERIOR PITUITARY Neurohypophysis ~ Posterior Lobe + InfundibulumNeural Portion (axons) is an extension of the Hypothalamus; Stores two “neurohormones” produced in the hypothalamus 1) Oxytocin ~ effects uterus & mammaries 2) Antidiuretic Hormone ~ ADH ~ retains water Neurohormones released into capillary beds of posterior pituitary in response to neural stimulation ~ Humoral

56 OXYTOCIN ~ “Post pit” PRODUCED in hypothalamus ~ Paraventricular Nuclei Uterus & Cervic Stretching during childbirth stimulates Released from Posterior Pituitary ~ Positive Feedback Effects: 1) Stimulates uterus muscle contraction 2) Stimulates mammaries to release & “let- down” 3) Stimulates sexual arousal & orgasm 4) Promotes nurturing & cuddling ~ “nesting” Highest Concentrations ~ during childbirth & nursing Synthetic Drug ~ induces labor & stimulates milk “letdown”

57 ANTIDIURETIC HORMONE ~ ADHWhat is “Diuresis”??? = Excess Urine production ADH = “Anti-Urine Hormone” = AGAINST DIURESIS “Vasopressin” ~ causes vasoconstriction & elevates Blood Pressure PRODUCED in hypothalamus ~ Supra Otic Nuclei Stimulated by need to retain fluids Dehydration ~ Excess sweating ~ no fluid intake Hemorrhage ~ Blood Loss Low blood pressure & Shock Released from Posterior Pituitary into blood

58 Effects: 1) Targets Kidneys ----> Water Retention 2) Prevents urine formation ----> water retention; Reabsorbs water back into blood in kidneys 3) Increases blood pressure ~ due to vasoconstriction & retained fluid volume in blood Controlled by Negative feedback “Shut-Off” Mechanism Inhibited by High Blood Volume High Blood Pressure. . . Fluid Retention Over-Hydration

59 ADH INHIBITORS ~ BLOCK ADH ~ “Diuretics”Stimulate urine production & fluid loss Results in copious urine production & output Flushes water from body ~ Dehydration Morning after dry mouth & intense thirst ~ drinking Decreases Blood Fluid Volume ----> lowers BP Examples of ADH Inhibitors ~ ALL act as DIURETICS Drinking excessive fluid & Alcoholic beverages Diuretic Drugs ~ Diet Pills ~ Dexetrene Hypertension Drugs ~ to lower blood pressure

60 Extremely vascular ~ Surgery very difficultTHYROID GLAND Largest “pure” endocrine ONLY gland in body ~ “Butterfly” On the trachea ... Anterior throat area … below the larynx Two lateral lobes connected by a median isthmus Blood Supply ~ via thyroid artery off common carotid artery Extremely vascular ~ Surgery very difficult

61 Internal Thyroid Tissue HistologyFollicular Cells - spherical cells ~ surround lumen; Produce thyroglobulin ~ glycoprotein 2. Lumen of follicle ~ stores colloid Colloid = thyroglobulin + attached iodine “Iodinated Thyroglobulin” Precursor for Thyroid Hormone ~ T3 or T4 3. Parafollicular Cells ~ around & between the follicle Endocrine cells that produce calcitonin Calcitonin ~ lowers blood calcium levels

62 Thyroid Gland is Unique . . .Only endocrine gland that stores hormones in large quantities ~ in colloid THYROID HORMONE ~ TH “Body’s major “metabolic hormone”

63 T4 (STORED) > > > T3 (“Active)Thyroid Hormone is two Iodine containing hormones T4 Thyroxine ~ STORED FORM ~ NOT ACTIVE 90% of TH ~ secreted by follicle cells T3 Triiodothyronine ~ NOT stored ~ “ACTIVE” Formed at target tissues by conversion of T4 (STORED) > > > T3 (“Active)

64 Effects of Thyroid HormoneThyroid Hormone affects most cells except: Brain ... Spleen ... Testes ... Uterus ... Thyroid Effects of Thyroid Hormone 1. Stimulates carbohydrate, lipid & protein metabolism Glucose & fat catabolism ~ energy produced Protein & cholesterol synthesis ~ growth 2. Increases basal metabolic rate & O2 consumption Calorigenic Effect ~ burn calories ~ body heat Promotes normal oxygen use by cells Regulates tissue growth, development, & function Thyroid Hormone Release ~ “Negative Feedback”

65 3. TSH ----> Thyroid to release thyroxin (T4 & T3) into blood 1. Falling blood levels of thyroxin (T4) ----> Hypothalamus to release thyrotropic releasing hormone (TRH) 2. TRH ----> anterior pituitary to release thyroid stimulating hormone (TSH) into blood 3. TSH ----> Thyroid to release thyroxin (T4 & T3) into blood 4. Thyroxin (T4 & T3) is carried to target organ receptors T3 is formed at the target tissue by conversion of T4 5. T3 or T4 actively exert effects on the target tissue 6. Rising blood levels of T3/T4 “shuts off” hypothalamus --> inhibits release of TRH (hypothalamus) & TSH (Ant. Pit)

66 Factors Triggering TSH release from anterior pituitary:Any conditions increasing body energy requirements Pregnancy ~ requires energy for fetus Prolonged Cold ~ requires body heat Extensive Exercise ~ requires energy & O2 Factors Inhibiting TSH release: Somatostatin ~ growth hormone inhibitor ~ less energy Rising levels of glucocorticoids ~ high blood sugar High blood iodine concentration ~ Stimulates excess TH ----> shuts off Hypothalamus

67 THYROID GLAND HORMONESCALCITONIN Produced by parafollicular cells of Thyroid Protein hormone ~ lowers blood Ca++ Direct antagonist to parathyroid hormone Mode of Action: 1) Targets skeletal tissue & bone 2) Inhibits osteoclast activity & bone resorption 3. Inhibits release of ionic calcium from bone 4. Stimulates calcium uptake into bone Stimulates osteoblast activity in bone

68 Calcitonin Secretion Stimuli:Cycles up & down with parathryroid hormone Excessive blood levels of calcium -----> “calcitonin” release ~ to lower blood calcium Part of “negative feedback” system with “parathyroid hormone” from parathyroid gland

69 PARATHYROID GLAND Very tiny ~ on posterior side of thyroid gland two pairs, one on each side ~ numbers can vary Function is antagonistic to thyroid gland Thyroid ~ calcitonin lowers blood Ca++ Parathyroid ~ parathyroid hormone raises blood Ca++

70 Histology of Parathyroid Tissue1. Chief Cells – round and dark stained Produce “Parathyroid Hormone” ~ PTH 2. Oxyphil Cells – function unknown 3. Capillaries - extensive network

71 Parathyroid Hormone ~ PTH ~ “Parathormone”Most important hormone controlling blood calcium levels PTH Secretion & Release Stimuli Low blood calcium levels (hypo-calcemia) ----> Stimulate Parathyroid Hormone release High blood calcium levels (hyper-calcemia) ----> inhibits Parathyroid Hormone release Main Effect of PTH ~ increases blood calcium ion levels Direct antagonist to calcitonin (lowers blood Ca++ )

72 Parathyroid Hormone ~ PTHBlood Calcium Balance ~ needed for many body functions: Nerve impulse transmission Muscle contraction Blood clotting Bone development & maintenance Mode of Action ~ Parathyroid Hormone 1. Skeletal Tissue ~ stimulates bone cells (osteoclasts) to release calcium from bone into blood 2. Kidney ~ enhances reabsorption of calcium into blood 3. Kidney ~ activates Vitamin D -----> increases intestinal absorption of Ca++

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74 ADRENAL GLAND ~ the “Stress Gland”Paired ~ pyramid shaped ~ On top of each kidney “suprarenal glands” ~ above the kidney

75 Each adrenal gland ~ two distinct glands in oneAdrenal Medulla – smaller interior part Adrenal Cortex – larger portion surrounds medulla Each produces different types of hormones BOTH are stimulated in response to stressful situations

76 Adrenal Cortex

77 Adrenal Gland

78 Mineralocorticoids (Aldosterone)Adrenal Cortex Adrenal Cortex Hormones Function Zona glomerulosa Mineralocorticoids (Aldosterone) Mineral & water balance Na+ retention Zona fasciculata Gluco-corticoids Cortico-steroids (Cortisone, Cortisol) Gluconeogenesis Energy Metabolism Anti-inflammatory Immune Supression Zona reticularis Gonado-corticoids (Androgen) Sex Hormones Adrenal Medulla Adrenal Medulla Hormones Catecholamines Adrenalin Epinephrine Nor-Epinephrine Increases BP Increases HR Dilates Bronchioles Decrease Peristalsis

79 ADRENAL CORTEX MINERALOCORTICOIDS ~ AldosteroneAldosterone ~ 95% of mineralo-corticoids Produced in Zona Glomerulosa Regulate Na+ concentration in body fluids & blood Retains Na+ ~ most vital ion causing fluid retention Sodium retention causes fluid retention ~ EDEMA Retains water & fluid ~ same effect as ADH

80 Water follows sodium > > > fluid retentionAldosterone Effects Reduces Na+ excretion from body Retains Na+ from urine in kidney tubules Retains Na+ from perspiration & saliva Water follows sodium > > > fluid retention Aldosterone Secretion Stimuli Anything Requiring Fluid Retention Decreased Na+ blood levels Decreased blood volume Shock Decreased blood pressure Dehydration Blood Loss

81 Aldosterone Release MechanismsRenin-Angiotensin-Aldosterone Mechanism ~ MAJOR 1. Low blood pressure or lost blood volume is sensed by juxtaglomerular apparatus in kidney 2. Kidney releases Renin into blood 3. Renin ----> Angiotensin I in blood Angiotensin I ----> Angiotensin II in blood 4. Angiotensin II stimulates adrenal cortex to release Aldosterone which ----> Na+ retention in the kidney 5. Na+ & water retained in the blood ---->increasing blood volume & blood pressure ~ decreased urine

82 ACTH ~ adrenocorticotropic hormone Other Aldosterone Release Mechanisms ~ MINOR ACTH ~ adrenocorticotropic hormone Severe stress ----> hypothalamus secretes corticotropin releasing hormone ----> anterior pituitary to secrete ACTH ----> release of Aldosterone ----> Sodium Retention Effects Atrial Natriuretic Peptide ~ ANP ~ inhibits aldosterone Increased blood pressures stimulates heart to release ANP which inhibits the renin-angiotensin mechanism ----> Na+ & water excretion & lower blood pressure

83 ADRENAL CORTEX HORMONESGLUCOCORTICOIDS ~ “Cortisone” Produced in Zona Fasciculata Cortisol ~ hydrocortisone ~ most significant Cortisone ~ produced in liver from cortisol

84 Glucocorticoid Effects ~ MANY1. Reduces stress ~ prepares body for crisis Thru gluconeogenesis & glycogenoslysis “Diabetogenic” Effect ~ ↑ blood sugar Converts glycogen to glucose Converts fats to glucose 2. Stimulates protein breakdown to amino acids 3. Anti-Inflammatory ~ reduces swelling ~ “cortisone” 4. Supresses immunity ~ organ transplants 5. Stimulates appetite ~ “cortisol” 6. Used as a synthetic drug ~ allergy & inflammation Cortisone Prednisone Hydrocortisone

85 Glucocorticoid Hormone Release - stimulated by stressPhysical & Emotional trauma Hemorrhage Illness Severe stress ----> hypothalamus secretes corticotropin releasing hormone ----> anterior pituitary to secrete ACTH ----> stimulates release of Cortisol & Cortisone

86 GONADOCORTICOIDS ~ Sex HormonesProduced in Zona Reticularis of Adrenal Cortex Mainly Androgen ~ male sex hormone ~ Testosterone Some Estrogen ~ female sex hormone Lower concentrations than ovaries & testis Significant levels ~ up to puberty ~ between ages of 7-13 Hyper-secretion could cause masculinization in children Early hair ~ beard Deeper voice Sexual aggressiveness

87 ADRENAL MEDULLA Centrally located in adrenal gland ~ Smaller portionSecretes CATECHOLAMINES - effects Sympathetic NS 80% Epinephrine & 20% Norepinephrine = Adrenaline Release: Stress stimulates the sympathetic nervous system ~ prepares body for crisis Immediate Response ~ “short acting”

88 Sympathomimetic Effects: Blood sugar rises Heart beats faster Blood pressure increases Bronchioles dilate ~ more air Pupils dilate ~ more light Digestion & Peristalsis Slows Visceral Vasodilation & Peripheral Vasoconstriction diverts Blood to where it is needed: From skin & digestive organs to brain, heart & skeletal muscle

89 MAJOR ENDOCRINE ORGANSPANCREAS Large, soft, triangular - posterior to stomach Mixed gland: Endocrine & Exocrine function

90 Exocrine Pancreas ~ 99% Ascinar Cells ~ epithelial cells ~ 99% of gland Digestive enzymes ducted into small intestine Amylase ~ carbohydrate breakdown Lipase ~ lipid breakdown Protease ~ protein breakdown

91 Endocrine Pancreas ~ 1% Islets of Langerhans~ 1% of Gland Tiny island cluster cells among Ascinar cells Alpha cells ~ secrete Glucagon Beta cells ~ secrete Insulin Both regulate blood glucose ~ effects are opposite Glucagon ~ raises blood glucose ~ hyper-glycemic Insulin ~ lowers blood glucose ~ hypo-glycemic

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93 GLUCAGON Protein produced in alpha cells ~ (islets of langerhans)Potent hyper-glycemic effects:  Blood Sugar Glucagon Secretion ~ Humoral Stimuli Stimulated by: Falling blood sugar levels Inhibited by: Rising blood sugar levels

94 Effects of Glucagon ~ Glucagon  Blood Sugar1. Breaks down glycogen to glucose ~ glycogenolysis 2. Stimulates Glucose Synthesis from fats & amino acids…. “gluconeogenesis” 3. Stimulates Release of glucose from liver into blood  blood sugar 4. Stimulates breakdown of protein to Amino Acids…. “Catabolic Effect”

95 INSULIN Small protein ~ made in beta cells ~ islets of langerhansPotent hypoglycemic effects  Blood Sugar Insulin Secretion ~ Humoral Stimuli Stimulated by: Rising blood sugar levels Eating a meal Other hyperglycemic hormones Glucagon Growth Hormone Thyroxin Glucocorticoids Adrenalin Inhibited by: Lower blood sugar levels

96 Major Effects of Insulin ~ opposite of glucagon1. Enhances glucose uptake & utilization by all cells 2. Stimulates glycogen storage in muscle & liver Inhibits Glycogenolysis ~ lowers blood sugar 3. Inhibits conversion of fats & amino acids to glucose Inhibits Gluconeogenesis ~ lowers blood sugar 4. Stimulates protein synthesis from amino acids “Anabolic Effect” 5. Stimulates Glucose conversion to fat for storage

97 Blood Glucose Feedback Mechanism

98 OTHER ENDOCRINE ORGANSPINEAL GLAND Tiny pine cone shaped in epithalamus of diencephalon Soft tissue landmark ~ pineal sand/calcium for brain X-rays

99 PINEAL GLAND Endocrine function is a mystery ~ biorythms/sleep-wake/temp MELATONIN ~ pineal gland hormone * Peak levels at night make us drowsy * Stimulation of pineal gland related to visual light * Influences sleep/wake cycle, body temperature, & appetite ~ biorythms

100 THYMUS Large in infants & children ~ provides immunity in childrenLocated deep to sternum in upper thorax at base of heart Becomes adipose tissue & connective tissue with age ~ scars

101 THYMUS Secretes hormones: Thymopoitens ThymosinsEffect: Normal development of T-lymphocytes ~ T-cells Important in the immune response ~ infant & young

102 GONADS Male Gonads ~ Testis Female Gonads ~ OvariesProduce more sex hormones than the adrenal cortex . . . Release regulated by FSH & LH gonadotropins from pituitary

104 OVARIES ESTROGEN ~ release influenced by FSHReleased from follicle cells of ovaries Causes maturation of reproductive organs Female secondary sex characteristics ~ puberty Menstrual cycle ~ uterus cyclic changes PROGESTERONE ~ release influenced by LH Released from corpus luteum ~ old follicle Maintains pregnancy ~ secreted for months

106 TESTES Testicular Hormones ~ male hormone ~ androgensTESTOSTERONE ~ release influenced by LH Produced in interstitial cells of testis Causes maturation of male reproductive organs Male secondary sex characteristics & sex drive Necessary for normal sperm production

107 OTHER HORMONE PRODUCING STRUCTURES. Not really endocrine glandsOTHER HORMONE PRODUCING STRUCTURES Not really endocrine glands but have other endocrine cells HEART Atrial wall stretched by excess fluid volume & pressure Releases: Atrial Natriuretic Peptide ~ ANP Effects of ANP: Inhibits Aldosterone release by adrenal cortex Inhibits sodium & fluid retention Reduces blood volume & lowers blood pressure

108 GASTROINTESTINAL TRACT (GIT) ORGANSSeveral Hormones Released to aid digestion Hormone Source Target Organ & Effect Gastrin Stomach Stomach HCL Release Serotonin Stomach Contraction Intestinal gastrin Duodenum Inhibits stomach HCL Slows GI Motility Secretin Inhibits gastric secretions Release bicarbonate from pancrease & liver Cholecystokinin Pancreatic juices & bile Amylase~CHO Lipase~Fats Protease~Proteins

109 Influences bone marrow to produce more RBC’s Renin KIDNEY Erythropoietin ~ EPO Influences bone marrow to produce more RBC’s Renin Stimulates Aldosterone SKIN Cholicalciferol Precursor to Vitamin D3 Intestine absorb of Ca++

110 HORMONES INVOLVED IN GROWTHInvolves coordination of several endocrine organs Important Hormones: Growth Hormone Thyroid Hormone Insulin Parathyroid Hormone Calcitrol ~ for Ca absorption Reproductive Hormones

111 HORMONES INVOLVED IN AGINGFew functional changes with age ~ most work until death Major changes involve decline of reproductive hormones Decline in Growth Hormone Other changes due to disease processes ~ i.e., diabetes

112 HORMONES INVOLVED IN STRESSStress Activates the General Adaptation Syndrome Involves: Hypothalamus Adrenal Gland Organs

113 Alarm Phase ~ immediate fight or flight ~ adrenalineNeural Stimulation ~ immediate ~ short acting Catecholamines: Epinephrine & Nor epinephrine Sympathetic Effects: ↑ BP ↑ HR ↓ Digestion