Hormones

Name: __________________ Topic: Hormones LO:Defineahormoneasachemicalsubstance,producedbyagland,carriedbytheblood,whichalterstheactivityofoneormorespecifictargetorgansandisthen destroyed by the liver Hormonesarechemicalsubstancesproducedbyendocrineglandsinminutequantities,transportedbybloodplasma, whichalterstheactivityofoneormoretargetorgansandisdestroyed by the liverandexcreted by the kidneys. LO: Explain what is meant by an endocrine gland, with reference to the islets ofLangerhans in the pancreas ● Endocrineglandsareductlessglandsthatproducesandreleaseshormones directly into the blood. ● Eg.IsletsofLangerhansinthepancreasare endocrineglandthatproducesandreleasesinsulinandglucagondirectlyinto the bloodplasmatobetransportedtothetargetorgans(e.g.liverandmuscles) toregulate blood glucose concentration. Concepts Summary NotesNan Hua High School Biology 1

Name: __________________ Topic: Hormones LO:Statetheroleofthehormoneadrenalineinboostingbloodglucoselevelsand give examples of situations in which this may occur ● Stimulus: Situations that encounter fear, anger and anxiety● Stimulatessensoryreceptorsandtransmitnerveimpulsesto thebrainwhichtransmitsnerveimpulsesto theeffector, adrenalglandwhichproducesandreleases adrenalineinto the blood to prepare thebody for fight/ flight response Effects of adrenaline:● Stimulatesliverandmusclecellsto convertstoredglycogento glucose,increasing the blood glucose levels● Increasein heartrateandbloodpressure, hencemoreoxygenandglucoseissupplied tomuscles for higher rate of respirationto release more energy● Constriction of arterioles in skinto allowmore bloodto the muscle tissues● Rateofventilationisincreasedforincreasedoxygensupplyforrespirationandremoval of carbon dioxide● Increase in metabolic ratetorelease more energyduringrespiration● Dilation of pupilto allowmore light in to enhancevision Concepts Summary NotesNan Hua High School Biology 2

Name: __________________ Topic: Hormones LO:Explainhowthebloodglucoseconcentrationis regulatedbyinsulinandglucagon as a homeostatic mechanism ChangesinbloodglucoseconcentrationstimulatesisletsofLangerhansofpancreastosecretemore insulin /glucagon After a heavy meal:● Blood glucose concentration increases above normal(stimulus)● Stimulates islets of Langerhans of pancreas to secrete more insulin● Insulinstimulates liver and muscle cellsto convertexcess glucose to glycogen● Increase permeabilityof cells forglucose uptake● Blood glucose concentrationdecreases back to normal Starvation:● Blood glucose concentration decreases below normal(stimulus)● Stimula