Pancreas & Adrenal Glands

Blood Sugar RegulationPancreas

Pancreas

PancreasTwo cell types to produce:digestive enzymes exocrine glands (acini)hormones islets of Langerhans

1 2% of pancreas are the islets of LangerhansIslets of LangerhansTwo hormones are produced:insulin beta () cellsglucagon alpha () cells

blue = cell nucleigreen = insulinred = glucagon

Hormone Structureinsulinpeptide hormone

glucagonpeptide hormone

Insulin and glucagon are referred to as antagonistic hormones.

GlycogenA glucose polymer made up of many glucose subunitsStorage form of glucoseStored within liver and muscle

Action of Insulinc

Beta cells ofpancreas are stimulatedto release insulininto the blood.InsulinLiver takesup glucoseand stores itas glycogen.Body cellstake up moreglucose.Blood glucose leveldeclines to set point;stimulus for insulinrelease diminishes.STIMULUS:Rising blood glucoselevel (for instance, aftereating a carbohydrate-rich meal)Homeostasis:Blood glucose level(about 90 mg/100 mL)Blood glucose levelrises to set point;stimulus for glucagonrelease diminishes.STIMULUS:Dropping blood glucoselevel (for instance, afterskipping a meal)Alpha cells of pancreasare stimulated to releaseglucagon into the blood.Liver breaksdown glycogenand releasesglucose intoblood.GlucagonFigure 45.12Example of Insulins Effect on Body Cells - Muscle Cell

Insulin ReceptorsInsulinGLUT 4 Protein VesiclesGLUT 4 Transporters (proteins that transport glucose across plasma membrane)Signal Transduction PathwayExocytosisGlucoseOUTSIDE CELLINSIDE CELLWhen is insulin released? after eatinghyperglycemiabeta cellscellular signals for insulin releasedecreased blood sugarincreased glucose uptakeglycogen production in liver

Beta cells ofpancreas are stimulatedto release insulininto the blood.InsulinLiver takesup glucoseand stores itas glycogen.Body cellstake up moreglucose.Blood glucose leveldeclines to set point;stimulus for insulinrelease diminishes.STIMULUS:Rising blood glucoselevel (for instance, aftereating a carbohydrate-rich meal)Homeostasis:Blood glucose level(about 90 mg/100 mL)Blood glucose levelrises to set point;stimulus for glucagonrelease diminishes.STIMULUS:Dropping blood glucoselevel (for instance, afterskipping a meal)Alpha cells of pancreasare stimulated to releaseglucagon into the blood.Liver breaksdown glycogenand releasesglucose intoblood.GlucagonAction of GlucagonWhat does glucagon do? breaks down glycogenhypoglycemiaalpha cellscellular signals for glucagon releaseincreased blood sugarglucose release from liverglucose production in liverDiabetes Mellitus Type Ialso known as juvenile diabetes or insulin-dependent diabetes

Causeimmune system attacking insulin-producing beta cellsno insulin production

Symptomsincreased thirst, hunger and urination

Treatmentdaily dosage of insulin

Diabetes Mellitus Type IIalso known as adult-onset diabetes or non-insulin-dependent diabetes

CausePoor diet, lack of exerciseExcess glucose in the blood for a long period of time causes the pancreas to become overworked and tiredBeta cells produce some, but not enough insulin (deficiency)A reduction in the number of functional insulin receptorsreduced responsiveness of cells to insulin = insulin resistant

Symptomsincreased thirst, hunger and urinationfatigue / lethargy

Type II DiabetesTreatmentmaintain healthy diet and frequent exercisemedication only upon progression of disease stateRegular exercise can reduce and stop symptomsInsulin GLUT 4 Protein VesiclesExocytosisExercise GLUT 4 Protein VesiclesInsulinGlucoseGlucoseCanadian ConnectionFrederick Banting & Charles BestNobel Prize 1923insulin isolationtied off ducts to digestive tractcell producing digestive enzymes shrivelledonly islets of Langerhans remained

Video TestimoniesUniversity of Albertadeveloped islet cell transplant method

Islet Transplant Animation

Photo Journal

News FeatureStress RegulationAdrenal Glandsadrenal next to the renal system

Two main sections:adrenal cortex long-term stressadrenal medulla short-term stress

Adrenal CortexLong-term stress sends ACTH (adrenocorticotropic hormone)

Anterior pituitaryadrenal cortex

Adrenal cortex produces two types of hormones:glucocorticoidsmineralcorticoidsACTH1. Glucocorticoidsclass of steroid hormones for glucose regulationspecific example: cortisol

What happens when youre stressed out?glucose not taken in by musclesamino acids made into glucosefat tissue broken down for energy

2. Mineralcorticoidsclass of steroid hormones for mineral regulationspecific example: aldosterone

What happens when youre stressed out?blood pressure rises due to increase sodium & H2O reabsorption in kidneys

Adrenal MedullaShort-term stress detected by hypothalamus

Produces two hormones:epinephrine (adrenaline)norepinephrine (noradrenaline)

both compounds are examples of catecholamines, which are also neurotransmittersHormone Structuresepinephrinehydrophilic

norepinephrinehydrophilic

Flight-or-Fight ResponseWhats your response?increased heart rateincreased breathingblood vessel dilation more O2 deliveryiris dilation collect maximum visual information

these responses are induced by catecholamine release

Spinal cord(cross section)NervesignalsNervecellReleasinghormoneStressHypothalamusAnterior pituitaryBlood vesselACTHAdrenalglandKidneyAdrenal medullasecretes epinephrineand norepinephrine.Adrenal cortexsecretesmineralocorticoidsand glucocorticoids.Effects of epinephrine and norepinephrine:

1. Glycogen broken down to glucose; increasedblood glucose2. Increased blood pressure3. Increased breathing rate4. Increased metabolic rate5. Change in blood flow patterns, leading to increased alertness and decreased digestive and kidney activityEffects ofmineralocorticoids:1. Retention of sodiumions and water bykidneys2. Increased bloodvolume and bloodpressureEffects ofglucocorticoids:1. Proteins and fatsbroken down andconverted to glucose,leading to increasedblood glucose2. Immune system maybe suppressed(b) Long-term stress response(a) Short-term stress response

Nerve cellClasswork/HomeworkSection 8.2 Pg. 383 #1-8,9