Foundation of Medicine Module

Endocrine SystemPhase 1 / Semester 1

2020/ 2021

Assist.Prof.Dr.Suhad Kadhum AliAl-Sadoon

F.I.B.M.S (General Surgery), M.B.Ch.B

Suhad.k.ali@uobabylon.edu.iq

ObjectivesvDefine endocrine glands and hormones

v Name the endocrine glands and the hormones they secrete.

v To know the location of the endocrine glands.

v Pronounce, spell, define, and write some medical terms related to the endocrine system.

Endocrine (to secrete) SystemThe endocrine system consists of several glands &located in many areas of the body. They secrete powerful chemicals called hormones into the bloodstream.Hormones secreted by glands to maintain the body’s normal temperature of about (37 degrees Celsius) regardless of the outside temperature.

The endocrine system: 2 parts: 1- peripheral2- central.

The peripheral endocrine glands1. Thyroid2. Parathyroids3. Adrenals4. Pineal5. Thymus6. Pancreas

productionthe:haveonlyonefunction4Thefirstofhormones.Thethymusproduces hormones andfunctions inimmunityThepancreas alsoproduces hormones andhasimportantdigestivefunctions.

2 central endocrine glands in the brain. 1.pituitary2.hypothalamus (high-poh-THAL-ah-mus).They are both in brain.

Central Endocrine Glands

Thyroid The thyroid located in neck and secretes below the larynx. It has right and left lobes connected by a structure called the isthmusT3 and T4. T3: triiodothyronineT4: thyroxine (thyroxin)Thyroxine:functions toRegulate metabolic rate

Parathyroid gland

Parathyroid glands

Therearefourparathyroidglands. therearetwooneachofthethyroid lobes.Theyareegg-shaped.Theseglandssecreteparathormone

travelstothebonetohelpPTHcalciumandregulate

phosphorus levels.

ThymusLocation:neartheheart inthoraciccavity.Itconsistof2lobe. EachlobecontainsmanysmallerlobescalledlobulesFunction:Thethymus isbothalymphaticorganandanendocrine gland.

,thethymusprotectsthelymphaticorganaAsbodyfromdisease.

,itsecretesahormoneendocrineglandAsancalledthymosin.Which stimulatered bonemarrowtoproduceTcells.

adrenal:Locationabovethekidneys.whichhas2parts1.cortexouterlayer2.medulla inner layer,which produce:

adrenaline (epinephrine )noradrenaline (norepinephrine )epinephrine andnorepinephrine preparethebodyfortimesofstressandfear

Adrenal Glands Supra-renal glands

The adrenal cortex : secretes the following hormones: v Aldosterone:regulatessodiumandpotassium

levels.v Cortisol :Itregulatesourimmune system, also

playsakeyroleinhowcarbohydrates, fats,andproteinsareusedbythebody.

v Sexhormon (estrogen, androgen):Theyaresecreted inverysmallamounts tomaintain2ndfemaleandmalesexcharacteristics suchashairgrowthandmusclebulk.

Adrenal Glands (Supra-renal glands)

PinealGland

´Location :likeapinecone&deepinthebrain.

´Secretion :secretesmelatonin.

´ Function :regulatessleepandwakingpatterns.

Pancreas

Thepancreas ispartofdigestive.It isa long,fish-shapedorganlyingbehindthestomach.Itisregulatebloodsugar.Hasdigestive andendocrinefunctions.

Thedigestive function:involvesthesecretionofdigestiveenzymestobreakdownfood.

Theendocrine function

isletsofLangerhans(LANG-er-hanz)whichcellinpancrease hasendocrinefunctionproduce2hormonesØ Insulin :whichissecretedfromB- cells.insulinlowersbloodglucose(sugar)by:1.stimulatingtheabsorptionofglucosebybodycells2.convertingglucosetoglycogen(storageinliver).Glucagon :whichissecretedfromalpha–cells.Thehormone glucagonincreasesbloodsugarbyconvertingglycogenbacktoglucosewhenthebodyrequiresenergytofunction.

Central Endocrine GlandsPituitary gland

also known as (hypophysis) locate at base of brain & secreat several hormones.consist: 2 lobes

Anterior.posterior.

Central Endocrine Glands(Pituitary gland)

The pituitary gland secretes several hormones

Anterior pituitary secretes:ACTH, Adrenocorticotropic .stimulatestheadrenalcortex.GH,Growthhormone .stimulatesgrowthinallbodycells.TSH, Thyroid-stimulating hormone .stimulatesthethyroidgland.Gonadotropic (FSH, LH,ICSH),stimulatethegonads(ovariesandtesticles).FSHstimulatesthemonthlydevelopment oftheegginthefollicle.LHtriggersovulationinfemales. ICSHregulatestestosteronesecretion.

PRL, Prolactin. stimulatesandmaintainsthesecretionofbreastmilk.MSHMelanocyte-stimulating hormone. stimulatestheskintoproducemelanocytes.

Posterior lobe of the pituitary

asanextensionofthehypothalamus.Itstoresandsecretestwohormonesproducedbythehypothalamus:

´ Antidiuretichormone(ADH)Itpreventsexcessivelossofwater.

´ Oxytocin(OXT)Itstimulatesuterinecontractions duringlabor,maintains laborduringchildbirth, andcausestheproductionofmilkfromthemammary glands

The hypothalamus locate deep in brain.Secrete: neurohormones, because the hormones are produced by neurons

The hypothalamus produces oxytocin and the antidiuretic hormone. These neurohormones are stored in the posterior pituitary

(hypothalamus)

parathyroid

Pineal gland hypothalamus

thyroid

pituitary

adrenals

thymus

pancreas

testisovary

Abbreviations of Major Hormones

adrenocorticotropic hormone ACTH antidiuretic hormone ADH follicle-stimulating hormone FSH growth hormone GH interstitial cell-stimulating hormone ICSH lactogenic hormone LTH luteinizing hormone LH oxytocin OXT parathormone PTH prolactin PRL somatotropic hormone STH thyroid-stimulating hormone TSH thyroxine T4 triiodothyronine T3

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