BILD 2: Multicellular LifeLECTURE #20Website: http://www.biology.ucsd.edu/classes/bild2.WI11.1Instructor: Darwin K. Berg ([email protected])ANNOUNCEMENTS:Prob Sets #5 & #6 have been posted on the website. Theyrepresent the final exams in two previous years.BloodvesselResponseResponseResponseResponse(a) Endocrine signaling(b) Paracrine signaling(c) Autocrine signaling(d) Synaptic signalingNeuronNeurosecretorycell(e) Neuroendocrine signalingBloodvesselSynapseResponsea) Secreted molecules diffuse into thebloodstream and trigger responses in targetcells anywhere in the body.b) Secreted molecules diffuse locally andtrigger a response in neighboring cells.c) Secreted molecules diffuse locally andtrigger a response in the cells that secretethem.d) Neurotransmitters diffuse acrosssynapses and trigger responses in cells oftarget tissues (neurons, muscles, orglands).e) Neurohormones diffuse into thebloodstream and trigger responses in target cells anywhere in the body.Fig. 45-2:IntracellularCommunicationby SecretedMoleculesFig. 45-3: Hormones differ in form and solubilityWater-solubleLipid-solubleSteroid:CortisolPolypeptide:InsulinAmine:EpinephrineAmine:Thyroxine0.8 nmFig. 45-5:ReceptorLocationVaries withHormoneTypeSignalreceptorTARGETCELLSignal receptorTransportproteinWater-solublehormoneFat-solublehormoneGeneregulationCytoplasmicresponseGeneregulationCytoplasmicresponseOR(a)NUCLEUS(b)a) Receptor in Plasma Membraneb) Receptor in Cell NucleusFig. 45-6: Cell-surface hormone receptors trigger signal transductioncAMPSecondmessengerAdenylylcyclaseG protein-coupledreceptorATPGTPG proteinEpinephrineInhibition ofglycogen synthesisPromotion ofglycogen breakdownProteinkinase AFig. 45-7: Steriod hormone receptors directly regulate gene expressionHormone(estradiol)Hormone-receptorcomplexPlasmamembraneEstradiol(estrogen)receptorDNAVitellogeninmRNAfor vitellogeninFig. 45-8: One hormone, different effects.Glycogendeposits receptorVesseldilates.Epinephrine(a) Liver cellEpinephrine receptorGlycogenbreaks downand glucoseis released.(b) Skeletal muscle blood vesselSame receptors but differentintracellular proteins (not shown)Epinephrine receptorDifferent receptorsEpinephrine receptorVesselconstricts.(c) Intestinal bloodvesselFig. 45-12:Maintenance ofglucosehomeostasisby insulin andglucagonHomeostasis:Blood glucose level(about 90 mg/100 mL)GlucagonSTIMULUS:Blood glucose levelfalls.Alpha cells of pancreasrelease glucagon.Liver breaksdown glycogenand releasesglucose.Blood glucoselevel rises.STIMULUS:Blood glucose levelrises.Beta cells ofpancreasrelease insulininto the blood.Liver takesup glucoseand stores itas glycogen.Blood glucoselevel declines.Body cellstake up
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