Chapter 45: Hormones & the Chapter 45: Hormones & the Endocrine SystemEndocrine System

Regulatory systemsRegulatory systemsNervous systemNervous system

High speed messagesHigh speed messagesEndocrine systemEndocrine system

Slower; longer lastingSlower; longer lastingResult of hormone secretionResult of hormone secretion

Connections between Nervous & Connections between Nervous & endocrine systemsendocrine systemsNeurosecretory cellsNeurosecretory cells

Nerve cells that release hormonesNerve cells that release hormonesConcentrated in hypothalamusConcentrated in hypothalamus

Some hormones act as neurotransmittersSome hormones act as neurotransmittersEx: epinephrineEx: epinephrine

HormonesHormones Chemical signal secreted into circulatory Chemical signal secreted into circulatory

system through ductless glandssystem through ductless glands Action of hormonesAction of hormones

Operate at all levels of organizationOperate at all levels of organization Intracellular, cell to cell, organ to organ, Intracellular, cell to cell, organ to organ,

organism to organism (pheromones)organism to organism (pheromones) Produce developmental changeProduce developmental change

Ex. pubertyEx. puberty Metamorphosis (insects & amphibians)Metamorphosis (insects & amphibians)

IncompleteIncomplete EggEggnymphnymphadult (grasshoppers)adult (grasshoppers)

CompleteComplete EggEgglarvalarvapupapupaadult (butterfly)adult (butterfly)

Regulation of hormonesRegulation of hormones Negative feedbackNegative feedback

Increase in substance inhibits its own productionIncrease in substance inhibits its own production Ex. Metabolic controlEx. Metabolic control

Positive feedbackPositive feedback Increase in substance increases its own productionIncrease in substance increases its own production Ex. Release of milk in nursing motherEx. Release of milk in nursing mother

Local regulatorsLocal regulators HistaminesHistamines

Chemical from local cell for antigen-antibody response Chemical from local cell for antigen-antibody response (allergies)(allergies)

InterleukinsInterleukins Cytokine acting as communicator between immune cellsCytokine acting as communicator between immune cells

ProstaglandinsProstaglandins Modified fatty acid which stimulates contraction of Modified fatty acid which stimulates contraction of

smooth muscles, induces fever & blood flow to infection smooth muscles, induces fever & blood flow to infection sitessites

Classes of molecules acting as Classes of molecules acting as hormoneshormones Proteins & peptides; HProteins & peptides; H22O solubleO soluble Amines (derived from amino acids); HAmines (derived from amino acids); H22O O

solublesoluble Steroids; non- HSteroids; non- H22O solubleO soluble

Events of hormone actionEvents of hormone action Reception (signal binds to receptor Reception (signal binds to receptor

protein in or on target cell)protein in or on target cell) Water soluble hormones bind to surface Water soluble hormones bind to surface

receptor triggering activation of internal receptor triggering activation of internal proteins in transduction pathwayproteins in transduction pathway

Steroid hormones enter cell & bind to internal Steroid hormones enter cell & bind to internal receptor which enters nucleus to activate receptor which enters nucleus to activate genesgenes

Signal transductionSignal transduction responseresponse

Endocrine GlandEndocrine Gland HormoneHormone Effect on target Effect on target tissuetissue

Anterior pituitary Anterior pituitary (adenohypophysis)(adenohypophysis)

FSHFSH Stimulate growth of Stimulate growth of ovarian follicle & ovarian follicle & sperm productionsperm production

LHLH Stimulate ovulation; Stimulate ovulation; secretion of sex secretion of sex hormones by hormones by ovaries/testesovaries/testes

ProlactinProlactin Induces milk Induces milk secretion in secretion in mammary glandsmammary glands

TSHTSH Stimulate throxin Stimulate throxin production by thyroidproduction by thyroid

ACTHACTH Stimulate adrenal Stimulate adrenal cortex to produce cortex to produce cortisonecortisone

GHGH Stimulate growthStimulate growth

MSHMSH Regulation of Regulation of pigment in skin cells; pigment in skin cells; inhibits hungerinhibits hunger

Beta endorphinBeta endorphin Dull pain perceptionDull pain perception

Endocrine GlandEndocrine Gland HormoneHormone Effect on Target Effect on Target tissuetissue

Posterior pituitary Posterior pituitary (neurohypophysis)(neurohypophysis)

ADHADH Stimulate increased Stimulate increased HH22O absorption by O absorption by kidneys; constrict kidneys; constrict blood vesselsblood vessels

OxytocinOxytocin Stimulate uterine Stimulate uterine contractions & contractions & release of milkrelease of milk

Thyroid glandThyroid gland Thyroxin (T4) & Thyroxin (T4) & Triiodothyronine (T3)Triiodothyronine (T3)

Stimulate oxidative Stimulate oxidative metabolismmetabolism

CalcitoninCalcitonin Regulation of calcium Regulation of calcium & phosphate blood & phosphate blood levelslevels

Parathyroid glandParathyroid gland Parathormone (PTH)Parathormone (PTH) Controls abosorption Controls abosorption of Ca & P from blood; of Ca & P from blood; stimulates release of stimulates release of Ca from boneCa from bone

ThymusThymus ThymosinThymosin Stimulates production Stimulates production of T lymphocytesof T lymphocytes

Adrenal cortexAdrenal cortex Cortisone*Cortisone* Regulate H2O Regulate H2O reabsorption, reabsorption, electrolyte balance, electrolyte balance, protein & protein & carbohydrate carbohydrate metabolismmetabolism

Endocrine glandEndocrine gland HormoneHormone Effect on target Effect on target tissuetissue

Adrenal medullaAdrenal medulla Epinephrine & Epinephrine & norepinephrinenorepinephrine

Raises blood glucose Raises blood glucose levels; increases levels; increases metabolic activity; metabolic activity; constricts blood constricts blood vesselsvessels

Pancreas (islet of Pancreas (islet of Langerhans)Langerhans)

Insulin (beta cells)Insulin (beta cells) Stimulates uptake of Stimulates uptake of glucose by cellsglucose by cells

Glucagon (alpha cells)Glucagon (alpha cells) Converts glycogen Converts glycogen into glucoseinto glucose

OvariesOvaries Estrogen*Estrogen* Stimulate female Stimulate female secondary sex secondary sex characteristics; build characteristics; build uterine lininguterine lining

Progesterone*Progesterone* Maintain pregnancyMaintain pregnancy

TestesTestes Testosterone*Testosterone* Stimulate male Stimulate male secondary sex secondary sex characteristicscharacteristics

PinealPineal MelatoninMelatonin Biological rhythmsBiological rhythms

*denotes steroid hormone

Endocrine DisordersEndocrine Disorders ThyroidThyroid

CretinismCretinism Under secretion of thyroxin in uteroUnder secretion of thyroxin in utero

GoiterGoiter Enlarged gland usually related to hypothyroidismEnlarged gland usually related to hypothyroidism

Graves diseaseGraves disease Most common form of hyperthyroidismMost common form of hyperthyroidism AutoimmuneAutoimmune

Hashimoto’s diseaseHashimoto’s disease Most common form of hypothyroidismMost common form of hypothyroidism autoimmuneautoimmune

PituitaryPituitary DwarfismDwarfism

Under secretion of GH in childUnder secretion of GH in child GiantismGiantism

Over secretion of GH in childOver secretion of GH in child Acromegaly Acromegaly

Over secretion of GH in adultOver secretion of GH in adult

PancreasPancreas Diabetes mellitusDiabetes mellitus

Type I (insulin dependant)Type I (insulin dependant) AutoimmuneAutoimmune Beta cells destroyed; little to no insulin productionBeta cells destroyed; little to no insulin production

Type IIType II Reduced responsiveness of target cells to insulinReduced responsiveness of target cells to insulin Controlled through diet & exerciseControlled through diet & exercise Accounts for >90% of diabetes casesAccounts for >90% of diabetes cases

Adrenal glandAdrenal gland Addison’s diseaseAddison’s disease

Under-secretion of ACTHUnder-secretion of ACTH