Upload
roger961
View
3.977
Download
1
Embed Size (px)
DESCRIPTION
Citation preview
1
The Endocrine The Endocrine SystemSystem
Chapter 17Chapter 17
2
Endocrine SystemEndocrine System
Overview Overview Endocrinology Endocrinology (endo = into crin (endo = into crin
= secrete)= secrete)
FunctionFunctionHormoneHormone
FYI “ A whopping increase of 165% in newly diagnosed Type 2 diabetes is expected by the year 2050. Among ethnic groups, the biggest increase is expected among black men (363%), with black women expected to see the second highest increase (217%).” From Live a Little, Laugh a Lot by Barb Bancroft
3
Overview of Cell Overview of Cell CommunicationsCommunications
MechanismsMechanisms gap junctionsgap junctions
pores in cell membrane pores in cell membrane Direct cell to cell Direct cell to cell
neurotransmittersneurotransmitters synapsesynapse
paracrine (local) paracrine (local) hormoneshormones
secreted into tissue fluids secreted into tissue fluids affect nearby cellsaffect nearby cells
interferoninterferon hormones hormones
4
Endocrine vs. Exocrine Endocrine vs. Exocrine GlandsGlands
Exocrine glandsExocrine glands ducts carry secretion to a surface ducts carry secretion to a surface extracellular effects (food extracellular effects (food
digestion)digestion) Endocrine glandsEndocrine glands
no ducts, release hormones into no ducts, release hormones into tissue fluids, capillary networks tissue fluids, capillary networks distribute hormonesdistribute hormones
intracellular effects, alter target intracellular effects, alter target cell metabolismcell metabolism
5
HormoneHormone chemical messenger stimulates response chemical messenger stimulates response
in other tissues or organsin other tissues or organs Target cellsTarget cells
Have hormone receptors Have hormone receptors Endocrine glandsEndocrine glands
produce hormonesproduce hormones Endocrine systemEndocrine system
endocrine organs (thyroid, pineal, etc)endocrine organs (thyroid, pineal, etc) hormone producing cells in organs (brain, hormone producing cells in organs (brain,
heart and small intestine)heart and small intestine)
Endocrine System Endocrine System ComponentsComponents
6
NervousNervous vs. vs. EndocrineEndocrine Systems Systems
7
NervousNervous and and EndocrineEndocrine Systems Systems
Some chemicals are both hormones and Some chemicals are both hormones and neurotransmittersneurotransmitters NE, cholecystokinin, thyrotropin-releasing NE, cholecystokinin, thyrotropin-releasing
hormone, dopamine and ADHhormone, dopamine and ADH Some hormones secreted by Some hormones secreted by
neuroendocrine cells (neurons)neuroendocrine cells (neurons) oxytocin and catecholaminesoxytocin and catecholamines
Systems regulate each otherSystems regulate each other neurons trigger hormone secretionneurons trigger hormone secretion hormones stimulate or inhibit neuronshormones stimulate or inhibit neurons
8
NomenclatureNomenclature
9
Endocrine OrgansEndocrine Organs
Major Major organs organs
10
HypothalamusHypothalamus
Floor and walls Floor and walls of third ventricleof third ventricle
Regulates Regulates functions from functions from water balance to water balance to sex drivesex drive
Many functions Many functions carried out by carried out by pituitary glandpituitary gland
11
Hypothalamic HormonesHypothalamic Hormones
12
Pituitary Gland Pituitary Gland
(Hypophysis)(Hypophysis) Location and sizeLocation and size Suspended from Suspended from
hypothalamus by stalk hypothalamus by stalk (infundibulum)(infundibulum)
housed in sella turcica housed in sella turcica of sphenoid boneof sphenoid bone
1.3 cm diameter1.3 cm diameter Adenohypophysis Adenohypophysis
(anterior pituitary)(anterior pituitary) NeurohypophysisNeurohypophysis
13
Secreted Hormones and the Secreted Hormones and the Portal SystemPortal System
Hormones Hormones travel in portal travel in portal system from system from hypothalamus hypothalamus to anterior to anterior pituitarypituitary
14
PRL (prolactin)PRL (prolactin) GH (growth hormone)GH (growth hormone) Tropic hormones target other glandsTropic hormones target other glands
gonadotropins target gonadsgonadotropins target gonads FSH (follicle stimulating hormone) FSH (follicle stimulating hormone) eggs and sperm eggs and sperm LH (luteinizing hormone)LH (luteinizing hormone)
ovulation; corpus luteum ovulation; corpus luteum estrogen, progesterone estrogen, progesterone Interstitial cells Interstitial cells testosterone testosterone
TSH (thyroid stimulating hormone) TSH (thyroid stimulating hormone) TH, gland growth TH, gland growth ACTH (adrenocorticotropic hormone)ACTH (adrenocorticotropic hormone)
Pituitary Pituitary Hormones Hormones Anterior LobeAnterior Lobe
15
ACTH or corticotropin (secreted by ACTH or corticotropin (secreted by corticotropes)corticotropes) regulates response to stress, stimulates regulates response to stress, stimulates
adrenal cortex adrenal cortex corticosteroids regulate glucose, fat and corticosteroids regulate glucose, fat and
protein metabolismprotein metabolism PRL (secreted by lactotropes)PRL (secreted by lactotropes)
female - milk synthesis after deliveryfemale - milk synthesis after delivery male - male - LH sensitivity, thus LH sensitivity, thus testosterone testosterone
secretionsecretion
Hormone Actions: Hormone Actions: Anterior LobeAnterior Lobe
16
Promotes tissue growth (bone, cartilage and muscle growth)Promotes tissue growth (bone, cartilage and muscle growth) mitosis & cellular differentiationmitosis & cellular differentiation stimulates liver to produce IGF-I (insulin like growth stimulates liver to produce IGF-I (insulin like growth
factors/somatomedins) and IIfactors/somatomedins) and II protein synthesis protein synthesis
DNA transciption, DNA transciption, mRNA, mRNA, proteins proteins amino acid transport into cells, amino acid transport into cells, protein protein
catabolismcatabolism lipid metabolism lipid metabolism
stimulates FFA and glycerol release from stimulates FFA and glycerol release from adipocytes, protein sparingadipocytes, protein sparing
CHO metabolismCHO metabolism glucose sparing effect = less glucose used for glucose sparing effect = less glucose used for
energyenergy Electrolyte balanceElectrolyte balance
promotes Napromotes Na++, K, K++, Cl, Cl-- retention, Ca retention, Ca 2+2+ absorption absorption
Growth Hormone Growth Hormone (Somatotropin)(Somatotropin)
17
Childhood and adolescenceChildhood and adolescence bone, cartilage and muscle growthbone, cartilage and muscle growth Stimulates growth at epiphyseal platesStimulates growth at epiphyseal plates
AdulthoodAdulthood increase osteoblastic activity affects bone increase osteoblastic activity affects bone
remodelingremodeling concentration decreases with age concentration decreases with age
Levels of GH (daily fluctuations)Levels of GH (daily fluctuations) during deep sleep, after high protein during deep sleep, after high protein
meals, after vigorous exercisemeals, after vigorous exercise lower after high CHO mealslower after high CHO meals
Growth Hormone and Growth Hormone and AgingAging
18
Hormone Actions: Posterior Hormone Actions: Posterior LobeLobe
Produced in hypothalamusProduced in hypothalamus transported to and stored in posterior transported to and stored in posterior
lobe lobe ADH (vasopressin)ADH (vasopressin)
targets kidneystargets kidneys water retention, reduce urinewater retention, reduce urine
also functions as a brain also functions as a brain neurotransmitterneurotransmitter
OxytocinOxytocin labor contractions, lactationlabor contractions, lactation possible role in possible role in
sperm transportsperm transport emotional bondingemotional bonding
19
Control of Pituitary: Control of Pituitary: Feedback from Target OrgansFeedback from Target Organs
Negative feedback Negative feedback target organ target organ
hormone levels hormone levels inhibits release of inhibits release of tropic hormonestropic hormones
Positive feedback stretching of uterus OT release, causes more stretching of uterus, until delivery
20
Endocrine DisordersEndocrine Disorders Hormone concentration and target cell Hormone concentration and target cell
sensitivity sensitivity Hyposecretion – inadequate hormone releaseHyposecretion – inadequate hormone release
tumor or lesion destroys glandtumor or lesion destroys gland head trauma affects pituitary gland’s head trauma affects pituitary gland’s
ability to secrete ADHability to secrete ADH diabetes insipidus = chronic polyuriadiabetes insipidus = chronic polyuria
Hypersecretion – excessive hormone releaseHypersecretion – excessive hormone release tumors or autoimmune disordertumors or autoimmune disorder
toxic goiter (graves disease) – antibodies toxic goiter (graves disease) – antibodies mimic effect of TSH on the thyroidmimic effect of TSH on the thyroid
21
Pituitary Pituitary DisordersDisorders
Hypersecretion of growth hormonesHypersecretion of growth hormones AcromegalyAcromegaly
middle-aged adults middle-aged adults abnormal growth of the hands/feet abnormal growth of the hands/feet
bone changes alter facial features bone changes alter facial features
including the spacing of teeth including the spacing of teeth arthritis arthritis thick, coarse, oily skin; skin tags; thick, coarse, oily skin; skin tags;
enlarged lips, nose and tongue; enlarged lips, nose and tongue; deepening of the voice due to deepening of the voice due to
enlarged sinuses and vocal cords; enlarged sinuses and vocal cords; snoring due to upper airway snoring due to upper airway obstruction; obstruction;
22
excessive sweating and skin odor; fatigue excessive sweating and skin odor; fatigue and weakness; headaches; impaired vision; and weakness; headaches; impaired vision;
enlargement of body organs, including the enlargement of body organs, including the liver, spleen, kidneys and heart.liver, spleen, kidneys and heart.
thickening of the bones and soft tissuesthickening of the bones and soft tissues problems in childhood or adolescenceproblems in childhood or adolescence
gigantism = oversecretion; dwarfism = gigantism = oversecretion; dwarfism = hyposecretion hyposecretion
23
Pineal GlandPineal Gland Peak secretion ages 1-5; by puberty 75% lowerPeak secretion ages 1-5; by puberty 75% lower May regulate timing of puberty in humansMay regulate timing of puberty in humans Produces serotonin by day, converts it to melatonin Produces serotonin by day, converts it to melatonin
at nightat night Melatonin Melatonin in SAD + PMS; in SAD + PMS; by phototherapy by phototherapy
depression, sleepiness, irritability and depression, sleepiness, irritability and carbohydrate cravingcarbohydrate craving“The pineal gland was called the "third eye" by ancient people. It was
thought to have mystical powers. This may be why the French philosopher Descartes decided that the pineal gland was the seat of the human soul, the location of what we call the mind.
Melatonin is released in the dark, during sleep. Melatonin has been shown to inhibit the growth and metastasis of some tumors in experimental animals, and may therefore play a role in cancer inhibition. Removal of the pineal gland and/or reduction in melatonin output have been implicated in the increased incidence of breast cancer in laboratory animals. Patients who have breast cancer have lower levels of melatonin in the blood. The hormone has also been shown to be protective against genetic damage, and it has a stimulatory effect on the immune system. “www.cayce.egympie.com.au/healthPinealGland.htm
24
ThymusThymus
Location: mediastinum, Location: mediastinum, superior to heartsuperior to heart
Involution after pubertyInvolution after puberty Hormones regulate Hormones regulate
development and later development and later activation of T-activation of T-lymphocyteslymphocytes thymopoietin and thymopoietin and
thymosinsthymosins
25
Thyroid Gland AnatomyThyroid Gland Anatomy Largest endocrine gland; high rate of blood Largest endocrine gland; high rate of blood
flowflow Anterior and lateral sides of tracheaAnterior and lateral sides of trachea
two large lobes connected by isthmus two large lobes connected by isthmus Thyroid folliclesThyroid follicles
filled with colloid and lined with simple filled with colloid and lined with simple cuboidal epithelial (follicular cells) that cuboidal epithelial (follicular cells) that secretes two hormones, Tsecretes two hormones, T3 3 and Tand T44
26
Thyroid GlandThyroid Gland Thyroid hormoneThyroid hormone
body’s metabolic rate and Obody’s metabolic rate and O22 consumptionconsumption
calorigenic effect - calorigenic effect - heat production heat production heart rate and contraction strengthheart rate and contraction strength respiratory raterespiratory rate stimulates appetite and breakdown stimulates appetite and breakdown
CHO, lipids and proteinsCHO, lipids and proteins alertness, bone growth/remodelingalertness, bone growth/remodeling
C (calcitonin or parafollicular) cellsC (calcitonin or parafollicular) cells produce calcitonin produce calcitonin blood Ca blood Ca2+ 2+ , ,
promotes Capromotes Ca2+ 2+ deposition and bone deposition and bone formation especially in childrenformation especially in children
27
Thyroid Gland DisordersThyroid Gland Disorders Congenital hypothyroidism (Congenital hypothyroidism ( TH) TH)
abnormal bone development, abnormal bone development, thickened facial features, low thickened facial features, low temperature, lethargy, brain damagetemperature, lethargy, brain damage
Myxedema (adult hypothyroidism, Myxedema (adult hypothyroidism, TH)TH) low metabolic rate, sluggishness, low metabolic rate, sluggishness,
sleepiness, weight gain, constipation, sleepiness, weight gain, constipation, dry skin and hair, cold sensitivity, dry skin and hair, cold sensitivity, blood pressure and tissue swellingblood pressure and tissue swelling
Endemic goiter (goiter = enlarged Endemic goiter (goiter = enlarged thyroid gland)thyroid gland) iodine deficiency, no TH, no - iodine deficiency, no TH, no -
feedback, feedback, TSH TSH Toxic goiter (Graves disease)Toxic goiter (Graves disease)
antibodies mimic TSH, antibodies mimic TSH, TH, TH, exophthalmos exophthalmos
Nodular pretibial myxedema
28
Parathyroid GlandsParathyroid Glands
PTH releasePTH release blood Cablood Ca2+ 2+ levelslevels promotes synthesis of promotes synthesis of
calcitriolcalcitriol absorption of Caabsorption of Ca2+ 2+
urinary excretionurinary excretion bone resorptionbone resorption
29
Parathyroid DisordersParathyroid Disorders
HypoparathyroidHypoparathyroid surgical excision during thyroid surgerysurgical excision during thyroid surgery fatal tetany 3-4 daysfatal tetany 3-4 days
Hyperparathyroid = excess PTH Hyperparathyroid = excess PTH secretionsecretion tumor in glandtumor in gland causes soft, fragile and deformed bonescauses soft, fragile and deformed bones blood Cablood Ca2+ 2+
renal calculirenal calculi
30
Adrenal Adrenal MedullaMedulla
Modified neurons called chromaffin cellsModified neurons called chromaffin cells releases catecholamines (epinephrine, NE)releases catecholamines (epinephrine, NE)
Long lasting hormonal effect Long lasting hormonal effect alertness, anxiety, or fearalertness, anxiety, or fear BP, heart rate and air flowBP, heart rate and air flow raises metabolic rateraises metabolic rate
inhibits insulin secretioninhibits insulin secretion stimulates gluconeogenesis and stimulates gluconeogenesis and
glycogenolysisglycogenolysis Stress causes medullary cells to stimulate Stress causes medullary cells to stimulate
cortexcortex
31
Adrenal CortexAdrenal Cortex LayersLayers
zona glomerulosa (outer) zona glomerulosa (outer) zona fasciculata (middle) zona fasciculata (middle) zona reticularis (inner)zona reticularis (inner)
32
Adrenal Adrenal CortexCortex
CorticosteroidsCorticosteroids mineralocorticoids (zona glomerulosa)mineralocorticoids (zona glomerulosa)
electrolyte balance, aldosterone electrolyte balance, aldosterone Na Na++ retention & retention & KK++ excretion excretion
glucocorticoids (zona fasciculata)glucocorticoids (zona fasciculata) especially cortisol, especially cortisol, fat and protein catabolism, fat and protein catabolism,
gluconeogenesis (from a.a.’s and FA’s) and gluconeogenesis (from a.a.’s and FA’s) and releases FAs and glucose into bloodreleases FAs and glucose into blood
anti-inflammatory effect becomes immune anti-inflammatory effect becomes immune suppression with long-term usesuppression with long-term use
sex steroids (zona reticularis)sex steroids (zona reticularis) androgen (including DHEA) and estrogen androgen (including DHEA) and estrogen
(important after menopause)(important after menopause)
33
Adrenal Adrenal DisordersDisorders Cushing syndrome - excess cortical Cushing syndrome - excess cortical secretionsecretion hyperglycemia, hypertension, weakness, hyperglycemia, hypertension, weakness,
edemaedema Muscle/bone loss occurs with protein Muscle/bone loss occurs with protein
catabolismcatabolism buffalo hump and moon face = fat buffalo hump and moon face = fat
deposition between shoulders or in face deposition between shoulders or in face Adrenogenital syndrome (AGS)Adrenogenital syndrome (AGS)
adrenal androgen hypersecretion; adrenal androgen hypersecretion; accompanies Cushingaccompanies Cushing
enlargement of external sexual organs in enlargement of external sexual organs in children and early onset of pubertychildren and early onset of puberty
masculinizing effects on women (deeper masculinizing effects on women (deeper voice and beard growth)voice and beard growth)
34
PancreaPancreass
Location - Retroperitoneal, inferior and dorsal to Location - Retroperitoneal, inferior and dorsal to stomachstomach
Exocrine – digestive enzymesExocrine – digestive enzymes Endocrine Endocrine
1-2 million islets produce hormones1-2 million islets produce hormones Insulin (from Insulin (from cells) cells)
secreted after CHO meal secreted after CHO meal glucose blood levels glucose blood levels stimulates glucose and amino acid uptakestimulates glucose and amino acid uptake nutrient storage effect (stimulates glycogen, nutrient storage effect (stimulates glycogen,
fat and protein synthesis)fat and protein synthesis)
35
Pancreatic HormonesPancreatic Hormones Glucagon (from Glucagon (from cells) cells)
secreted in very low carbohydrate secreted in very low carbohydrate and high protein diet or fastingand high protein diet or fasting
stimulates glycogenolysis, fat stimulates glycogenolysis, fat catabolism and absorption of AAs catabolism and absorption of AAs for gluconeogenesis for gluconeogenesis
Somatostatin (from delta (Somatostatin (from delta () ) cells)cells) secreted with secreted with in blood glucose in blood glucose
and AAs after a mealand AAs after a meal paracrine secretion = inhibits paracrine secretion = inhibits
secretion of insulin, glucagon by secretion of insulin, glucagon by and and cells cells
36
Pancreatic HormonesPancreatic Hormones Hyperglycemic hormones raise Hyperglycemic hormones raise
blood glucoseblood glucose GH, epinephrine, NE, cortisol and GH, epinephrine, NE, cortisol and
corticosteronecorticosterone Hypoglycemic hormones lower Hypoglycemic hormones lower
blood glucoseblood glucose insulininsulin
37
Diabetes MellitusDiabetes Mellitus
Signs and symptoms of hyposecretion of Signs and symptoms of hyposecretion of insulininsulin polyuria, polydipsia, polyphagiapolyuria, polydipsia, polyphagia hyperglycemia, glycosuria, ketonuriahyperglycemia, glycosuria, ketonuria osmotic diuresisosmotic diuresis
blood glucose levels rise above transport blood glucose levels rise above transport maximum of kidney tubules, glucose maximum of kidney tubules, glucose remains in urine (ketones also present)remains in urine (ketones also present)
increased osmolarity draws water into increased osmolarity draws water into urineurine
38
Types of Diabetes Types of Diabetes MellitusMellitus
Type I (IDDM) - 10% of casesType I (IDDM) - 10% of cases autoimmune destruction of autoimmune destruction of cells, cells,
diagnosed ~ 12diagnosed ~ 12 treat with diet, exercise, monitoring of treat with diet, exercise, monitoring of
blood glucose and insulin injectionsblood glucose and insulin injections Type II (NIDDM) - 90%Type II (NIDDM) - 90%
insulin resistanceinsulin resistance failure of target cells to respond to failure of target cells to respond to
insulininsulin risk factors: heredity, age (40+) and obesityrisk factors: heredity, age (40+) and obesity treat with weight loss, diet and exercisetreat with weight loss, diet and exercise oral medications improve insulin secretion oral medications improve insulin secretion
or target cell sensitivityor target cell sensitivity
39
Pathology of DiabetesPathology of Diabetes Acute pathology: cannot absorb glucose, breakdown Acute pathology: cannot absorb glucose, breakdown
fat and proteins (weight loss, weakness)fat and proteins (weight loss, weakness) fat catabolism fat catabolism FFA’s in blood and ketone bodies FFA’s in blood and ketone bodies ketonuria ketonuria osmotic diuresis, loss of Na osmotic diuresis, loss of Na++ and K and K++
ketoacidosis occurs as ketones ketoacidosis occurs as ketones blood pH blood pH causes dyspnea and eventually diabetic comacauses dyspnea and eventually diabetic coma
Chronic pathologyChronic pathology chronic hyperglycemia leads to neuropathy and chronic hyperglycemia leads to neuropathy and
cardiovascular damage from atherosclerosiscardiovascular damage from atherosclerosis retina and kidneys (common in type I), retina and kidneys (common in type I),
atherosclerosis leads to heart failure (common in atherosclerosis leads to heart failure (common in type II), and gangrenetype II), and gangrene
40
HyperinsulinismHyperinsulinism From excess insulin injection or From excess insulin injection or
pancreatic islet tumorpancreatic islet tumor Causes hypoglycemia, weakness and Causes hypoglycemia, weakness and
hungerhunger triggers secretion of epinephrine, GH triggers secretion of epinephrine, GH
and glucagonand glucagonside effects: anxiety, sweating and side effects: anxiety, sweating and HRHR
Insulin shockInsulin shock uncorrected hyperinsulinism with uncorrected hyperinsulinism with
disorientation, convulsions or disorientation, convulsions or unconsciousness unconsciousness
41
OvaryOvary Granulosa cells Granulosa cells
produces estradiol, first half of cycleproduces estradiol, first half of cycle Corpus luteum Corpus luteum
follicle after ovulationfollicle after ovulation produce estradiol and progesterone produce estradiol and progesterone
Functions of estradiol and progesteroneFunctions of estradiol and progesterone development of female reproductive development of female reproductive
system and physique including bone system and physique including bone growthgrowth
regulate menstrual cycle, sustain regulate menstrual cycle, sustain pregnancypregnancy
prepare mammary glands for lactation prepare mammary glands for lactation Both secrete inhibin: suppresses FSH secretionBoth secrete inhibin: suppresses FSH secretion
42
TestesTestes Interstitial cells (between Interstitial cells (between
seminiferous tubules)seminiferous tubules) produce testosterone and estrogenproduce testosterone and estrogen
FunctionsFunctions development of male reproductive development of male reproductive
system and physiquesystem and physique sustains sperm production and sex sustains sperm production and sex
drivedrive Sustentacular sertoli cellsSustentacular sertoli cells
secrete inhibin which suppresses secrete inhibin which suppresses FSH & stabilizes sperm production FSH & stabilizes sperm production ratesrates
43
Endocrine Functions of Other Endocrine Functions of Other OrgansOrgans Heart – Heart –
atrial natriuretic peptide (ANP) released with an atrial natriuretic peptide (ANP) released with an in BPin BP
blood volume and blood volume and BP by BP by Na Na++ and H and H22O loss by O loss by kidneyskidneys
Skin - helps produce vitamin DSkin - helps produce vitamin D3 3 calcitriol calcitriol (( blood blood Ca)Ca)
LiverLiver 15% of erythropoietin (stimulates bone marrow)15% of erythropoietin (stimulates bone marrow) angiotensinogen (a prohormone)angiotensinogen (a prohormone)
precursor of angiotensin II precursor of angiotensin II BP BP source of IGF-I (works with GH)source of IGF-I (works with GH) converts vitamin D3 to calcidiol converts vitamin D3 to calcidiol Hepcidin – promotes intestinal absorption of ironHepcidin – promotes intestinal absorption of iron
44
Endocrine Functions of Other Endocrine Functions of Other
OrgansOrgans KidneysKidneys erythropoietin – stimulates production of RBC’serythropoietin – stimulates production of RBC’s convert angiotensinogen to angiotensin Iconvert angiotensinogen to angiotensin I converts calcidiol to calcitriol (active form of vitamin converts calcidiol to calcitriol (active form of vitamin
D) D) absorption by intestine and inhibits loss in the absorption by intestine and inhibits loss in the
urineurine more Camore Ca2+ 2+ available for bone depositionavailable for bone deposition
Stomach and small intestines (10 enteric hormones)Stomach and small intestines (10 enteric hormones) coordinate digestive motility and secretion coordinate digestive motility and secretion
PlacentaPlacenta secretes estrogen, progesterone and otherssecretes estrogen, progesterone and others
regulate pregnancy, stimulate development of fetus regulate pregnancy, stimulate development of fetus and mammary glandsand mammary glands
45
Hormone ChemistryHormone Chemistry SteroidsSteroids
derived from cholesterolderived from cholesterol sex steroids, sex steroids,
corticosteroidscorticosteroids Peptides and glycoproteinsPeptides and glycoproteins
OT, ADH; all releasing OT, ADH; all releasing and inhibiting hormones and inhibiting hormones of hypothalamus; most of of hypothalamus; most of anterior pituitary anterior pituitary hormoneshormones
Monoamines (biogenic Monoamines (biogenic amines)amines) derived from amino acidsderived from amino acids
catecholamines catecholamines (norepinephrine, (norepinephrine, epinephrine, epinephrine, dopamine) and thyroid dopamine) and thyroid hormoneshormones
46
Hormone Synthesis: Steroid Hormone Synthesis: Steroid HormonesHormones
Synthesized from Synthesized from cholesterol – cholesterol – differs in differs in functional groups functional groups attached to 4-attached to 4-ringed steroid ringed steroid backbonebackbone
47
Hormone TransportHormone Transport Monoamines and peptides are hydrophilic Monoamines and peptides are hydrophilic
mix easily with blood plasma mix easily with blood plasma Steroids and thyroid hormone are hydrophobic Steroids and thyroid hormone are hydrophobic
must bind to transport proteins for transportmust bind to transport proteins for transport bound hormonebound hormone - attached to transport protein, - attached to transport protein,
prolongs half-life to weeksprolongs half-life to weeks protects from enzymes and kidney filtrationprotects from enzymes and kidney filtration
unbound hormoneunbound hormone leaves capillary to reach target leaves capillary to reach target cell (half-life a few minutes)cell (half-life a few minutes)
Transport proteins in blood plasmaTransport proteins in blood plasma albumin, thyretin and TGB (thyroxine binding albumin, thyretin and TGB (thyroxine binding
globulin) bind to thyroid hormoneglobulin) bind to thyroid hormone steroid hormones bind to globulins (transcortin)steroid hormones bind to globulins (transcortin) aldosterone - no transport protein, 20 min. half-lifealdosterone - no transport protein, 20 min. half-life
48
Hormone ReceptorsHormone Receptors
Located on plasma membrane, Located on plasma membrane, mitochondria, other organelles, or in mitochondria, other organelles, or in nucleusnucleus
Usually thousands for given hormoneUsually thousands for given hormone hormone binding turns metabolic hormone binding turns metabolic
pathways on or offpathways on or off Exhibit specificity and saturationExhibit specificity and saturation
49
Hormone Mode of ActionHormone Mode of Action
Hydrophobic Hydrophobic hormoneshormones penetrate penetrate
plasma plasma membrane – membrane – enter nucleusenter nucleus
Hydrophilic Hydrophilic hormones hormones must bind to must bind to
cell-surface cell-surface receptorsreceptors
50
Hormone ClearanceHormone Clearance
Hormone signals must be turned offHormone signals must be turned off Take up and degraded by liver and Take up and degraded by liver and
kidneykidney Excreted in bile or urineExcreted in bile or urine Metabolic clearance rate (MCR)Metabolic clearance rate (MCR) Half-life - time required to clear 50% Half-life - time required to clear 50%
of hormoneof hormone
51
Hormone InteractionsHormone Interactions
Most cells sensitive to more than one Most cells sensitive to more than one hormone and exhibit interactive effectshormone and exhibit interactive effects
Synergistic effectsSynergistic effects Permissive effectsPermissive effects
one hormone enhances response to a second one hormone enhances response to a second hormonehormone
Antagonistic effects Antagonistic effects
52
Stress and Adaptation Stress and Adaptation
StressStress upsets homeostasis and threatens upsets homeostasis and threatens
well-beingwell-being General adaptation syndrome General adaptation syndrome
way body reacts to stressway body reacts to stress occurs in 3 stagesoccurs in 3 stages
1.1. alarm reactionalarm reaction
2.2. stage of resistancestage of resistance
3.3. stage of exhaustionstage of exhaustion
53
Alarm ReactionAlarm Reaction
Initial responseInitial response epinephrine and norepinephrine levelsepinephrine and norepinephrine levels HR and HR and BP BP blood glucose levelsblood glucose levels Sodium and water retention Sodium and water retention
(aldosterone)(aldosterone)
54
Stage of ResistanceStage of Resistance
After a few hours, glycogen reserves After a few hours, glycogen reserves gonegone
ACTH and cortisol levelsACTH and cortisol levels Fat and protein breakdownFat and protein breakdown GluconeogenesisGluconeogenesis Depressed immune functionDepressed immune function Susceptibility to infection and ulcersSusceptibility to infection and ulcers
55
Stage of ExhaustionStage of Exhaustion Stress that continues until fat reserves Stress that continues until fat reserves
are goneare gone Protein breakdown and muscle wasting Protein breakdown and muscle wasting Loss of glucose homeostasisLoss of glucose homeostasis Hypertension and electrolyte imbalances Hypertension and electrolyte imbalances
(loss of K(loss of K++ and H and H++)) Hypokalemia and alkalosis leads to deathHypokalemia and alkalosis leads to death
56
Paracrine SecretionsParacrine Secretions Chemical messengers that diffuse short Chemical messengers that diffuse short
distances and stimulate nearby cellsdistances and stimulate nearby cells not produced in neurons or transported in bloodnot produced in neurons or transported in blood
Examples and their functionsExamples and their functions histamine histamine
from mast cells in connective tissue from mast cells in connective tissue causes relaxation of blood vessel smooth musclecauses relaxation of blood vessel smooth muscle
nitric oxide nitric oxide from endothelium of blood vessels, causes vasodilationfrom endothelium of blood vessels, causes vasodilation
somatostatin somatostatin inhibits secretion of islet alpha and beta cellsinhibits secretion of islet alpha and beta cells
catecholamines catecholamines diffuse from adrenal medulla to cortexdiffuse from adrenal medulla to cortex
57
Eicosanoids: a Paracrine Eicosanoids: a Paracrine SecretionSecretion LeukotrienesLeukotrienes
mediates allergic and inflammatory reactionsmediates allergic and inflammatory reactions Prostacyclin Prostacyclin (by cyclooxygenase)(by cyclooxygenase)
inhibits blood clotting and vasoconstrictioninhibits blood clotting and vasoconstriction Thromboxanes Thromboxanes (by cyclooxygenase)(by cyclooxygenase)
produced by blood platelets after injury; produced by blood platelets after injury; override prostacyclin, stimulates override prostacyclin, stimulates vasoconstriction and clottingvasoconstriction and clotting
Prostaglandins Prostaglandins (by cyclooxygenase)(by cyclooxygenase): : diverse; diverse; includesincludes PGE: relaxes smooth muscle in bladder, PGE: relaxes smooth muscle in bladder,
intestines, bronchioles, uterus and stimulates intestines, bronchioles, uterus and stimulates contraction of blood vesselscontraction of blood vessels
PGF: opposite effectsPGF: opposite effects
58
ReviewReview
ThyroidThyroid
PancreasPancreas
PinealPineal
ThymusThymus
melatoninmelatonin
thymopoietthymopoietinin
calcitonincalcitonin
glucagonglucagon
59
FSHFSH
GnRHGnRH
ADHADH
EstrogenEstrogen
OTOT
LHLH
PTHPTH
Parathyroid hormoneParathyroid hormone
Antidiuretic hormoneAntidiuretic hormone
Luteinizing hormoneLuteinizing hormone
Follicle stimulating Follicle stimulating hormonehormone
OxytoxinOxytoxin
Gonadotropin Gonadotropin releasing hormonereleasing hormone
EstrogenEstrogen
60
61
62
63
64
65
66
67
68
69
70
71
72