highgearwhenthereisdanger.Itismorecommonlyknownasthe“fightorflight”response.When
thereistheperceptionofdanger,theanimalisticorlowerpartofthebrainistriggeredtocoordinate
thereleaseofcertaincompoundsintothebloodstream,twoofthemostsignificantbeingadrenaline
andcortisone...topromotethesurvivaloftheanimalorperson.ThisiscoordinatedbytheSympath-
etic Nervous System (SNS).
Adrenalineandcortisoneexertnumerousphysiologicaleffectsonthebody,allofwhicharegearedto
maximizingphysicalstrengthandendurance,sothatthepersoncanescapethedanger,eitherbyrun-
ningawayfromitorfightingtheirwayoutofit.Inatruecrisis(seriousaccidentsornearaccidents,
etc.)wherethereisimminentdanger,theincreasedheartrateallowsforbloodtobepumpedrapidly
tothemuscles,sotheycanbemobilizedtorunorfight,andtothelungssothebloodcanbeoxygen-
atedtosupplyfueltothemuscles.Otherphysiologicalchangesincludesdilationofthepupils,togive
alargerscopeofvisionsoonecanbetterseetheiroptionsofescape,increasedbloodpressureresult-
ingfromtheincreasedheartratecoupledwithadecreaseinthediameterofthevessels(constriction),
themobilizationofenergybyreleasingfatsandglucoseintothebloodstream,andareleaseofblood
coagulationfactorssothatintheeventofinjury,thebloodcanclotquicklytominimizebloodloss.In
addition,bloodsupplyisdecreasedtotheareasofthebodythataredeemednottobevitaltotheim-
mediatesurvival,suchasthedigestive,urinaryandintegumentsystem(skin),andsenttothepartsof
the body where it can be used more efficiently, namely the heart and muscles.
The First Phase of the Stress Response: The SNS Geared for Life or Death Situation:
- Hypothalamus(Brain)–PituitaryGland(EndocrineSys-
tem)–StimulatesAdrenalGlands–ProduceAdrenaline&
Cortisol: - HeartBeatsFaster&HardertoPumpblood....BloodPres-
sure Rises abruptly - High-energy fats dumped into the blood for energy
- Blood sugar increases
- Chemicalsreleasedtomakebloodclotmorequickly(in
case of injury) - OtherSNSresponses(pupilsdilate,bowelsempty,sweat-
ing, etc.)
ThesecondphaseofTheStressResponseistherecoveryphase,wheretheenergyplummetsafterthe
crisishaspassed.Thisisfollowedbythethirdphaseinwhichthephysiologicalprocessesnormalize;
the heart rate and blood pressure return to normal.
Adrenalinehasanothernamethatitusedinmedicalinstitutions.Recallanytelevisionshowyou
watchedwheretherewasascenewheresomeone’sheartstoppedbeating.Whatisthefirstdrugthat
thedoctorscalledfor?Epinephrine.Epinephrineisanothertermforadrenaline.Inemergencyroom
situationswhereapatient’sheartstopsbeating,epinephrineisgiventostimulatetheheartbeat.