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Two systems coordinate communication throughout the body: the endocrine system and the nervous systemThe endocrine system secretes hormones that coordinate slower but longer-acting responses including reproduction, development, energy metabolism, growth, and behaviorThe nervous system conveys high-speed electrical signals along specialized cells called neurons; these signals regulate other cells

LECTURE PRESENTATIONSFor CAMPBELL BIOLOGY, NINTH EDITIONJane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson 2011 Pearson Education, Inc.Lectures byErin BarleyKathleen Fitzpatrick

Hormones and the Endocrine SystemChapter 45

Andre the Giant had acromegaly: HGH secreted in adulthoodTo what would hyposecretion of HGH in childhood lead?

Glands of the endocrine system

Lets review stuff we know

Whats the difference?EndocrineParacrineAutocrine

Methods of intercellular communication by secreted molecules(a) Endocrine signalingBlood vesselResponseResponseResponseSynapseResponseResponse(b) Paracrine signaling short distances(c) Autocrine signaling short distancesNeuron(d) Synaptic signalingNeurosecretory cellBlood vessel(e) Neuroendocrine signaling

Whats the difference?EndocrineExocrine

How do they work differently?ProteinSteroid

Synaptic and Neuroendocrine SignalingIn synaptic signaling, neurons form specialized junctions with target cells, called synapses

At synapses, neurons secrete molecules called neurotransmitters that diffuse short distances and bind to receptors on target cells

In neuroendocrine signaling, specialized neurosecretory cells secrete molecules called neurohormones that travel to target cells via the bloodstream

Signaling by Pheromones, hormones outside the selfPheromones serve many functions, including: marking trails leading to food, defining territories, warning of predators, and attracting potential mates

Figure 45.4Major endocrine glands:HypothalamusPineal glandPituitary glandThyroid glandParathyroid glands (behind thyroid)Adrenal glands (atop kidneys)PancreasOvaries (female)Testes (male)Organs containing endocrine cells:ThymusHeartLiverStomachKidneysSmall intestine

Lipid-soluble (hydrophobic)Water-soluble (hydrophilic)PolypeptidesSteroids0.8 nmInsulinCortisolAminesEpinephrineThyroxine3 Chemical classes of hormones ( or two )

PathwayExampleStimulusLow pH in duodenumEndocrine cellS cells of duodenum secrete the hormone secretin ( ).HormoneBlood vesselTarget cellsPancreasResponseBicarbonate releaseNegative feedbackA simple endocrine pathway

PathwayExampleStimulusSucklingSensory neuronPositive feedbackHypothalamus/ posterior pituitaryNeurosecretory cellNeurohormoneBlood vesselTarget cellsResponsePosterior pituitary secretes the neurohormone oxytocin ( ).Smooth muscle in breastsMilk releaseA simple neuroendocrine pathway

Receptor location varies with hormone type.Lipid- soluble hormoneSECRETORY CELLWater- soluble hormoneVIA BLOODSignal receptorTARGET CELL(a)(b)Signal receptorTransport proteinNUCLEUS

Figure 45.6-2Lipid- soluble hormoneSECRETORY CELLWater- soluble hormoneVIA BLOODSignal receptorTARGET CELLORCytoplasmic responseGene regulation(a)(b)Cytoplasmic responseGene regulationSignal receptorTransport proteinNUCLEUS

Animation: Water-Soluble Hormone Right-click slide / selectPlay

Figure 45.7-1 Epinephrine (aka) adrenaline, has multiple effectsEpinephrineG proteinAdenylyl cyclaseG protein-coupled receptorGTPATPcAMPSecond messenger

Figure 45.7-2EpinephrineG proteinAdenylyl cyclaseG protein-coupled receptorGTPATPcAMPSecond messengerInhibition of glycogen synthesisPromotion of glycogen breakdownProtein kinase A

Animation: Lipid-Soluble Hormone Right-click slide / selectPlay

Steroid hormone receptors directly regulate gene expressionEXTRACELLULAR FLUIDHormone (estradiol)Estradiol (estrogen) receptorPlasma membraneHormone-receptor complex

Figure 45.8-2EXTRACELLULAR FLUIDHormone (estradiol)Estradiol (estrogen) receptorPlasma membraneHormone-receptor complexNUCLEUSDNACYTOPLASMVitellogeninmRNA for vitellogenin

Multiple Effects of HormonesThe same hormone may have different effects on target cells that have for two reasons:

Multiple Effects of HormonesThe same hormone may have different effects on target cells that have for two reasons:Different receptors for the hormoneDifferent signal transduction pathways

Different receptorsSame receptors but different intracellular proteins (not shown)Different cellular responsesDifferent cellular responsesEpinephrineEpinephrineEpinephrine receptor receptor receptorGlycogen depositsVessel dilates.Vessel constricts.Glycogen breaks down and glucose is released from cell.(a) Liver cellOne hormone, different effects

Multiple Effects of HormonesThe same hormone may have different effects on target cells that have for two reasons:Different receptors for the hormoneDifferent signal transduction pathways

AlsoPerception of physical responsee.g. Love on a bridge study

What functions hormones control

Figure 45.1What signals caused this butterfly to grow within the body of a caterpillar?

BrainNeurosecretory cellsCorpora cardiacaCorpora allataPTTHProthoracic glandEcdysteroidJuvenile hormone (JH)EARLY LARVARegulation of insect development and metamorphosis

BrainNeurosecretory cellsCorpora cardiacaCorpora allataPTTHProthoracic glandEcdysteroidJuvenile hormone (JH)EARLY LARVALATER LARVARegulation of insect development requires multiple hormones

BrainNeurosecretory cellsCorpora cardiacaCorpora allataPTTHProthoracic glandEcdysteroidJuvenile hormone (JH)Low JHEARLY LARVALATER LARVAPUPAADULTFigure 45.10-3

Maintenance of glucose homeostasis is done by paired hormones, insulin and glucagonInsulinBeta cells of pancreas release insulin into the blood.Homeostasis: Blood glucose level (70110 mg/100 mL)STIMULUS: Blood glucose level rises (for instance, after eating a carbohydrate-rich meal).

Figure 45.13a-2Body cells take up more glucose.InsulinBeta cells of pancreas release insulin into the blood.Liver takes up glucose and stores it as glycogen.Blood glucose level declines.Homeostasis: Blood glucose level (70110 mg/100 mL)STIMULUS: Blood glucose level rises (for instance, after eating a carbohydrate-rich meal).

Figure 45.13b-1Homeostasis: Blood glucose level (70110 mg/100 mL)GlucagonSTIMULUS: Blood glucose level falls (for instance, after skipping a meal).Alpha cells of pancreas release glucagon into the blood.

Figure 45.13b-2Blood glucose level rises.Homeostasis: Blood glucose level (70110 mg/100 mL)Liver breaks down glycogen and releases glucose into the blood.Alpha cells of pancreas release glucagon into the blood.GlucagonSTIMULUS: Blood glucose level falls (for instance, after skipping a meal).

Diabetes MellitusDiabetes mellitus is perhaps the best-known endocrine disorderIt is caused by a deficiency of insulin or a decreased response to insulin in target tissuesIt is marked by elevated blood glucose levels

Type 1 diabetes mellitus (insulin-dependent) is an autoimmune disorder in which the immune system destroys pancreatic beta cells Type 2 diabetes mellitus (non-insulin-dependent) involves insulin deficiency or reduced response of target cells due to change in insulin receptors

45.3 Coordination of Endocrine and Nervous Systems in VertebratesThe hypothalamus receives information from the nervous system and initiates responses through the endocrine systemAttached to the hypothalamus is the pituitary gland, composed of the posterior pituitary and anterior pituitary

Pineal glandCerebellumSpinal cordCerebrumThalamusHypothalamusPituitary glandPosterior pituitaryAnterior pituitaryHypothalamusFigure 45.14The posterior pituitary stores and secretes hormones that are made in the hypothalamusThe anterior pituitary makes and releases hormones under regulation of the hypothalamus

Thyroid glandhypothalamusanteriorpituitarygonadotropic hormones:follicle-stimulatinghormone (FSH) & luteinizing hormone (LH)Mammaryglandsin mammalsMusclesof uterusKidneytubulesposteriorpituitarythyroid-stimulating hormone(TSH)antidiuretic hormone(ADH)AdrenalcortexBoneand muscleTestesOvariesMelanocytein amphibianadrenocorticotropic hormone (ACTH)melanocyte-stimulating hormone(MSH)oxytocinprolactin (PRL)growth hormone (GH)tropic hormones = target endocrine glands

Table 45.1a

Table 45.1b

Thyroid Regulation: A Hormone Cascade PathwayA hormone can stimulate the release of a series of other hormones, the last of which activates a nonendocrine target cell; this is called a hormone cascade pathwayThe release of thyroid hormone results from a hormone cascade pathway involving the hypothalamus, anterior pituitary, and thyroid glandHormone cascade pathways typically involve negative feedback

A hormone cascade pathwayPathwayExampleStimulusColdSensory neuronHypothalamusNeurosecretory cellReleasing hormoneBlood vesselAnterior pituitaryTropic hormoneEndocrine cellHormoneTarget cellsResponseNegative feedbackHypothalamus secretes thyrotropin-releasing hormone (TRH ).Anterior pituitary secretes thyroid-stimulating hormone (TSH, also known as thyrotropin ).Thyroid gland secretes thyroid hormone (T3 and T4 ).Body tissuesIncreased cellular metabolism

Evolution of Hormone FunctionOver the course of evolution the function of a given hormone may diverge between speciesFor example, thyroid hormone plays a role in metabolism across many lineages, but in frogs has taken on a unique function: stimulating the resorption of the tadpole tail during metamorphosis

Hormones as homologous structuresprolactinWhat does this tell you about these hormones?gene duplication?How could these hormones have different effects?

Melanocyte-stimulating hormone (MSH) regulates skin color in amphibians, fish, and reptiles by controlling pigment distribution in melanocytesIn mammals, MSH plays additional roles in hunger and metabolism in addition to coloration

Parathyroid gland (behind thyroid)PTHHomeostasis: Blood Ca2 level (about 10 mg/100 mL)STIMULUS: Falling blood Ca2 levelThe roles of parathyroid hormone (PTH) in regulating blood calcium levels in mammals.

Active vitamin DIncreases Ca2 uptake in intestinesStimulates Ca2 uptake in kidneysStimulates Ca2 release from bonesParathyroid gland (behind thyroid)PTHBlood Ca2 level rises.Homeostasis: Blood Ca2 level (about 10 mg/100 mL)STIMULUS: Falling blood Ca2 levelFigure 45.20-2

Epinephrine and norepinephrineTrigger the release of glucose and fatty acids into the bloodIncrease oxygen delivery to body cells Direct blood toward heart, brain, and skeletal muscles and away from skin, digestive system, and kidneysThe release of epinephrine and norepinephrine occurs in response to involuntary nerve signalsMultiple hormonal pathways/effects during fight or flight

Effects of stress on a bodySpinal cord(cross section)NervesignalsNervecellReleasinghormoneStressHypothalamusAnterior pituitaryBlood vesselACTHAdrenalglandKidneyadrenal medullasecretes epinephrine& norepinephrineAdrenal cortexsecretesmineralocorticoids& glucocorticoids(B) LONG-TERM STRESS RESPONSE(A) SHORT-TERM STRESS RESPONSE

Nerve cellEffects of epinephrine and norepinephrine:

1.Glycogen broken down to glucose; increased blood glucose2.Increased blood pressure3.Increased breathing rate4.Increased metabolic rate5.Change in blood flow patterns, leading to increased alertness & decreased digestive & kidney activityEffects of mineralocorticoids:

1.Retention of sodium ions & water by kidneys

2.Increased blood volume & blood pressureEffects of glucocorticoids:

1.Proteins & fats broken down & converted to glucose, leading to increased blood glucose

2.Immune system suppressedMEDULLACORTEX

Spinal cord (cross section)(a)(b)Long-term stress response and the adrenal cortexShort-term stress response and the adrenal medullaStressNerve signalsNerve cellReleasing hormoneHypothalamusAnterior pituitaryBlood vesselNerve cellACTHAdrenal medulla secretes epinephrine and norepinephrine.Adrenal glandKidneyAdrenal cortex secretes mineralo- corticoids and glucocorticoids.Effects of epinephrine and norepinephrine:Effects of mineralocorticoids:Effects of glucocorticoids:Glycogen broken down to glucose; increased blood glucoseIncreased blood pressure Increased breathing rateIncreased metabolic rateChange in blood flow patterns, leading to increased alertness and decreased digestive, excretory, and reproductive system activity Retention of sodium ions and water by kidneys Increased blood volume and blood pressure Proteins and fats broken down and converted to glucose, leading to increased blood glucose Partial suppression of immune systemFigure 45.21

Glucocorticoids, such as cortisol, influence glucose metabolism and the immune systemMineralocorticoids, such as aldosterone, affect salt and water balance

The adrenal cortex also produces small amounts of steroid hormones that function as sex hormones

Sex HormonesThe gonads, testes and ovaries, produce most of the sex hormones: androgens, estrogens, and progestinsAll three sex hormones are found in both males and females, but in significantly different proportions

The testes primarily synthesize androgens, mainly testosterone, which stimulate development and maintenance of the male reproductive systemTestosterone causes an increase in muscle and bone mass and is often taken as a supplement to cause muscle growth, which carries health risksIt has been suggested by some scientists that the ratio of two digits in particular, the 2nd (index finger) and 4th (ring finger), is affected by exposure to testosterone (androgens) in the uterusLow 2D:4D is positively correlated with success in sport

Discovery article about ratio outcomes

Chromosome SetAppearance of GenitaliaNo surgeryEmbryonic gonad removedXY (male)XX (female)MaleFemaleFemaleFemaleRESULTSWhat role do hormones play in making a mammal male or female?

Melatonin and BiorhythmsThe pineal gland, located in the brain, secretes melatoninLight/dark cycles control release of melatonin

Did you know?One reason that kittens sleep so much is because a growth hormone is released only during sleep.

The levels of two stress hormones, cortisol and epinephrine which suppress the body's immune system, will actually drop after a dose of laughter.

Chocolate is associated with the release of serotonin, the hormone that makes you feel relaxed, calm, and happy. So are hugs.

***Figure 45.2 Intercellular communication by secreted molecules.***Figure 45.4 Major human endocrine glands.*Figure 45.5 Hormones differ in structure and solubility.*Figure 45.11 A simple endocrine pathway.*Figure 45.12 A simple neuroendocrine pathway.*Figure 45.6 Receptor location varies with hormone type.*Figure 45.6 Receptor location varies with hormone type.**Figure 45.7 Cell-surface hormone receptors trigger signal transduction.*Figure 45.7 Cell-surface hormone receptors trigger signal transduction.**Figure 45.8 Steroid hormone receptors directly regulate gene expression.*Figure 45.8 Steroid hormone receptors directly regulate gene expression.***Figure 45.9 One hormone, different effects.**Figure 45.1 What signals caused this butterfly to grow within the body of a caterpillar?*Figure 45.10 Regulation of insect development and metamorphosis.*Figure 45.10 Regulation of insect development and metamorphosis.*Figure 45.10 Regulation of insect development and metamorphosis.*Figure 45.13 Maintenance of glucose homeostasis by insulin and glucagon.*Figure 45.13 Maintenance of glucose homeostasis by insulin and glucagon.*Figure 45.13 Maintenance of glucose homeostasis by insulin and glucagon.*Figure 45.13 Maintenance of glucose homeostasis by insulin and glucagon.****Figure 45.14 Endocrine glands in the human brain.*tropins (tropic hormones) stimulate growth in target organs/cells (tropic means nourishment) When the target organ is another gland, tropic hormones cause them to produce & release their own hormones.*Table 45.1 Major Human Endocrine Glands and Some of Their Hormones*Table 45.1 Major Human Endocrine Glands and Some of Their Hormones**Figure 45.17 A hormone cascade pathway.**The most remarkable characteristic of prolactin (PRL) is the great diversity of effects it produces in different vertebrate species. For example, prolactin stimulates mammary gland growth and milk synthesis in mammals; regulates fat metabolism and reproduction in birds; delays metamorphosis in amphibians, where it may also function as a larval growth hormone; and regulates salt and water balance in freshwater fishes. This list suggests that prolactin is an ancient hormone whose functions have diversified during the evolution of the various vertebrate groups.

Growth hormone (GH) is so similar structurally to prolactin that scientists hypothesize that the genes directing their production evolved from the same ancestral gene. Gene duplication!**Figure 45.20 The roles of parathyroid hormone (PTH) in regulating blood calcium levels in mammals.*Figure 45.20 The roles of parathyroid hormone (PTH) in regulating blood calcium levels in mammals.**Figure 45.21 Stress and the adrenal gland.****Figure 45.22 Inquiry: What role do hormones play in making a mammal male or female?*