ENDOCRINE SYSTEM System of ductless glands Regulates body functions via hormones secreted into the bloodstream

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ENDOCRINE SYSTEM System of ductless glands

Regulates body functions via hormones secreted into the bloodstream.


Major Endocrine Glands: Hypothalamus

Pituitary Gland

Thyroid Gland

Parathyroid Gland


Adrenal GlandOther organs containing endocrine tissue:




Digestive Tract





2. PITUITARY GLAND Pea sized mass of glandular tissue Lies in sella turcicaSlender stalk: Infundibulum connects pituitary gland to hypothalamus2 parts : Neurohypophysis AdenohypophysisIndirectly controls :GrowthMetabolismSexual reproductionLactation

PITUITARY GLAND: HORMONESHORMONESEFFECTSOxytocin (OC)Stimulates contraction of uterus & contractile cells of breastADHPrevents excess urine productionGHGeneral body growthACTHStimulate adrenal cortex to release hormoneTSHControls thyroid glandLHStimulates sexual & reproductive functionFSHStimulate production of sperm & egg in ovaries & testisMSHRelated to skin pigmentationPRLInitiates milk production in breast Anterior PituitaryPosterior PituitaryTHYROID GLANDLocated in middle anterior part of neck: below larynx, in front of tracheaButterfly shape2 lobes connected by isthmus in size : puberty & pregnancyRich blood supply: able to deliver high levels of hormones in short period of timeProduces Thyroxin (T4) & Tri-iodothyronine (T3)Calcitonin : involved in calcium & phosphate homeostasis

PARATHYROID GLAND Small rounded massAttached to posterior surface of thyroid glandProduces Parathyroid hormone (PTH)Controls homeostasis of calcium & phosphate in blood by activating Vitamin D

THYMUSPlays a role in the immune system

Produces thymosin, thymic humaral factor & thymic factor

Responsible for maturation of T-lymphocytes

HORMONES OF THYROID, PARATHYROID & THYMUSORGANHORMONEEFFECTThyroid gland (Follicular cells)T3 & T4 energy utilization oxygen consumption growth & developmentThyroid gland(C cells)Calcitonin Calcium ion concentration in body fluidsParathyroidPTH Calcium ion concentration in body fluidsThymusThymosinMaturation & functional competence of immune system ADRENAL GLANDLocated superior to the kidney

Divided into: (i) outer cortex (ii) inner medulla

ADRENAL GLANDADRENAL CORTEXADRENAL MEDULLASecretes steroid hormonesSecretes hormones controlled by ANS

Glucocorticoids (metabolism) eg. cortisolEpinephrine (Adrenaline)Mineralocorticoids (homeostasis of ions) eg. Aldosterone

Norepinephrine (Noradrenaline)Gonadocorticoids (oestrogens & androgens)

ADRENAL HORMONESEFFECTHARMONESREGIONcardiac activityblood pressureglycogen breakdownblood glucoseEpinephrine (Adrenaline), Norepinephrine (Noradrenaline)MedullaAndrogens3. Zona ReticularisReleases amino acids from skeletal muscle & lipids from adipose.Promotes liver glycogen & glucose formationAnti inflammatory effectGlucocorticoid: cortisol2. Zona fasciculataRenal reabsorption of sodium ions & water.renal potassium ion lossMineralocorticoid: AldosteroneCortex1. Zona glomerulos PANCREASFlattened organ Lies retroperitoneally & transversly across posterior abdominal wallPosterior to stomach, between doudenum on right & spleen on leftClassified as exocrine & endocrineHormones:Islets of Langerhans secrete: Glucagon, cells : blood glucose Insulin, cells: blood glucoseGrowth harmone inhibiting hormone (GHIH), cells : inhibits glucagon & insulin

HORMONES OF PANCREASCELLSHARMONEEFFECTAlpha () cellsGlucagonGlucose synthesis & glycogen breakdown in liver Blood glucose concentrationBeta () cellsInsulinStimulation of lipids & glycogen storage & formation Blood glucose concentrationDelta () cellsSomatostatinInhibits secretion of insulin & glucagonTESTES & OVARIESTESTES:Located within scrotumProduce testosteroneStimulates development of male sexual characteristics

OVARIES:Located in pelvic cavityProduce oestrogen & progesteroneResponsible for development & maintenance of female characteristics & menstrual cycle

HORMONES OF REPRODUCTIVE SYSTEMCELLSHORMONESEFFECTTestes Interstitial cells1. Testosterone2. Inhibin1. Maturation of sperm Male secondary sex characteristics2. Inhibits secretion of FSH OvariesFollicle cells1. Oestrogen2. Inhibin1. Follicle maturation Female secondary sex characteristic2. Inhibits secretion of FSHCorpus LuteumProgesteronePrepare uterus for implantationPrepare breast for secretory functionOTHER ENDOCRINE TISSUESKIDNEYS: Renal Erythropoietic factor: erythropoietin

HEART: Atrial Natriuretic factor (ANF)

Gastrointestinal: Stomach gastrin, enteric gastrin, secretin, cholecystokinin, enterocinin, gastric inhibiting hormone

PLACENTA: Human chorionic gonadotropin, oestrogen, progesterone, relaxinENDOCRINE DISORDERS2 Categories: Abnormal hormone production Abnormal cellular sensitivity

ACROMEGALY:Over production of growth hormone after the epiphyseal plates have fusedBone shape changesCartilaginous areas of skeleton enlargeBroad facial featuresEnlarged lower jaw

ENDOCRINE DISORDERSCRETINISMResults from thyroid hormone insufficiency in infancy

ENDOCRINE DISORDERSGOITEREnlarged thyroid glandResults from thyroid hormone hyposecretion Due to iodine insufficiency

ENDOCRINE DISORDERSCUSHINGS SYNDROMEResults from hypersecretion of glucocorticoidsLipid reserves are mobilizedAdipose tissue accumulates in cheeks & base of neck


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