Topic 13Topic 13

The endocrine systemThe endocrine system

Content by Megan McDonald

HormonesHormonesA chemical substance produced by a

group of cells that is secreted into the blood stream to affect the function of other glands or organs in the body.

Target organsTarget organsOnly specific organs respond to

particular hormones

Hormone physiologyHormone physiology

Hormones alter cellular activity by changing

rate of metabolic processes of target cells.

usual metabolic process of target cells

Hormone classificationHormone classificationLipid solubleSteroid hormonesTwo thyroid hormones – T3 and

T4Nitric Oxide

Lipid soluble hormone Lipid soluble hormone actionaction Lipid soluble hormone diffuses

from blood, across the plasma membrane into a cell

If a target cell hormone binds to receptors in cytosol or nucleus and turns specific genes on or off

A new protein (often enzyme) is made

The protein alters the cells activity and causes the hormone response.

Hormone ClassificationHormone ClassificationWater solubleAmine hormonesPeptide and protein hormonesEicosanoid hormones.

Water soluble hormone Water soluble hormone actionaction Hormone binds to receptor on cell

membrane Binding causes ATP to convert to

cyclic AMP cAMP causes cellular proteins to

activate or deactivate, changing the cells activities.

After a short time cAMP is switched off by phosphodiestrase.

Pancreatic ActionPancreatic ActionSkip breakfastBlood sugar level lowAlpha cells of pancreatic islets

release glucagonGlucagon causes liver cells to

release glucose into blood, rapidly.

Blood sugar level rises.

Pancreatic actionPancreatic actionEat a doughnut for breakfast Blood sugar level lowBeta cells of pancreatic islets

release insulin.Insulin acts on various cells to

accelerate diffusion of glucose into the cells

Blood sugar levels return to normal.

Insulin actionInsulin actionGlucose diffuses into skeletal

muscle fibres.Slows formation of glucose from

fatty acids.Slows formation of glucose from

lactic acid and amino acids.

Endocrine glandsEndocrine glandsSecrete hormones into the blood

stream directlyDuctless

Exocrine glandsExocrine glandsSecrete their products into ducts Ducts open onto surface

Exocrine glandsExocrine glandsSudoriferous (sweat)Sebaceous (oil)SalivaryMucosal cellsLiverIntestinal glandsPancreasMammary glands

Activity 13.1Activity 13.1Colouring book.Qu 5. pg 182

Activity 13.2Activity 13.2Marieb workbook chapter 6Qu 4. p.181Qu. 6 p. 183Qu. 7 p. 183

Topic 16Topic 16

The reproductive The reproductive systemsystem

Male reproductive systemMale reproductive system

Internal structuresTestesDuctal systemUrethra

Male reproductive systemMale reproductive system

External structures (genitalia)PenisScrotum

Male reproductive systemMale reproductive system

Accessory glandsSeminal vesicleProstate glandBulbourethral gland

Male reproductive systemMale reproductive system

Fluid produced by male reproductive system containing -

SpermNutrientsMucosa

Semen

FunctionFunctionProduce sperm for delivery to the

female reproductive tract.Produce testosterone.

Sperm productionSperm productionBegins at pubertyContinues throughout lifeSpermatogenesis takes 64 -72

days

SpermSpermMade in testesDevelop in seminiferous tubules1 sperm fertilizes an ovum50 – 100 million sperm/millilitre

semen

TestosteroneDevelopment of male sexual

characteristicsControl of sperm maturationControl of sperm productionInfluences sexual behaviour

TestosteroneTestosteroneProduced in interstitial cells of

testes.Cells activated in puberty Luteinising hormone (LH) from

anterior pituitary gland.

TestosteroneTestosteroneStimulate development of

reproductive hormonesMale secondary sex

characteristics.

Secondary sex Secondary sex characteristicscharacteristicsEnlargement of larynx - deep voicePubic, axillary, chest and facial hairMuscular skeletal growth – wide

shoulders/narrow hips.Increased sebaceous gland secretionThickening of skin

Activity 16.2Activity 16.2Marieb workbook chapter 16Qu 9. p. 325

Female reproductive Female reproductive systemsystemInternal structuresVaginaUterusUterine (fallopian) tubesovaries

Female reproductive Female reproductive systemsystemExternal structures (Genitalia)

VulvaMons pubisLabiaClitorisUrethral and vaginal orificesBartholins glands

Activity 16.3Activity 16.3Marieb workbook chapter 16Qu 10. p. 325Qu 11. p. 326Qu 12. p. 327

FunctionFunctionProduction of ova (oocytes)Facilitate fertilisationFacilitate transportation, nuturing

of foetus

Ovarian cycleOvarian cycleOvarian follicles contain

immature ovaFSH released from Ant. Pituitary

glandFSH stimulates some immature

ova to mature each monthThis occurs for 30 – 40 years.

Ovarian cycleOvarian cycleOvulationMature follicle rupturesEgg released into peritoneal

cavityEgg swept into fallopian tube for

fertilisationFinishes at menopause (40-50

y.o)

Activity 16.4Activity 16.4Marieb workbook chapter 16Qu 16. p. 329

Menstrual cycleMenstrual cycle

When ova is unfertilisedEndometrial layer of uterus

breaks downExpelled via vaginaCyclical over 28 days (+/-)Occurs in response to hormones

in blood

Menstrual cycle – phase 1Menstrual cycle – phase 1Days 1 – 5Menstrual phaseFSH release by anterior pituitaryFollicle development beginsMenstrual flow 50-150ml

blood, tissue fluid, epithelial cells.Declining progesterone and oestrogen

Menstrual cycle – phase 1IMenstrual cycle – phase 1IDays 6 -14Proliferative phaseEndometrium is proliferating 4 -

10mmFollicle in ovary growing and

bulgingEstrogen production by mature

follicle increases.Ends in ovulation of (usually) one

ovum

Menstrual cycle – phase Menstrual cycle – phase 1II1IIDays 15 – 28Secretory phaseEndometrial glands secrete

glycogenEndometrium thickens to 12-

18mmCorpus luteum secretes

progesterone and estrogens

Mammary glandsMammary glandsModified sweat glands 15 -20 lobes radiating around

nippleProduce milk during lactationProduction stimulated by

prolactinRelease stimulated by oxytocin

from post. Pituitary and sucking action

Fertilisation & EmbryonicFertilisation & EmbryonicDevelopment Development

FertilisationFertilisationMale sperm + ovum = zygote

Usually occurs in distal fallopian tube

Embryonic developmentEmbryonic developmentDevelopment begins immediatelyImplants in endometrial layer of

uterusPlacenta forms

PlacentaPlacenta

SuppliesNutritionOxygenRemoves wasteProduces hormones

Embryonic developmentEmbryonic developmentProgresses rapidly for first 2

months9 weeks – Foetus40 week pregnancyConcludes with labour and

childbirth.

Activity 16.7Activity 16.7Marieb workbook chapter 16Qu 22. p. 333Qu 28. p. 335Qu 31. p. 336Qu 33. p. 336

Thank you!Thank you!