Objec&ves:
•  Todaywewill…
–  Handbackgene&cstests
–  Notes:Homeostasis
–  Video:BreakingDown
•  Sothatwecan…
–  Definehomeostasis
–  Drawnega&vefeedbackloopstoshowhoweachorgan
systemhelpstomaintainhomeostasisinthebody.
BellWork:
•  PleasetakeoutyourUnit4Trackers,updatewith
yourfinalgradesforourgene&csunit,andcomplete
thereflec&onattheboLomofthepage.
•  Iwillcomearoundtocollectyourreflec2onsheet
andyourtest.
•  Pleasekeepyourtestinforma2onprivate.Ifyou
wishtodiscussgrades,pleasedosooutsideofclass.
•  Removeallunit4materialsfromyourbinder,clip
themtogetherwithabinderclip,andplacethemin
theboxinthefrontoftheroom.
Brainstorm:
Allbodysystemsworktomaintainnormal,
stablecondi&onswithinyourbody.
List3examplesofhow
normalcondi&onsin
yourbodycouldbe
disrupted.(Ex:Illness)
Humansarefragile!
“I’mhot!”
“I’mcold!”
“Ouch,Icutmyself!” “Phew,I’mthirsty!”
“Ugh,Ihavetheflu!”
“Grr,I’mhungry!”
“Mymusclesaresore!” And,theenvironmentaroundusis
constantlychanging!
DefineHomeostasis:
Allbodysystemsworktomaintainnormal,
stablecondi&onswithinyourbody.
StopandJot:
•  Howisthisperson’shomeostasisdisrupted?
Howdoesthisperson’sclotheshelphimto
maintainhomeostasis?
•  Usethewords:
–  External
–  Internal
–  Disrupt
–  Homeostasis
TheBodyMaintainsHomeostasisThrough:
Nega2veFeedbackLoop=Aprocessin
whichoppositeac2onsworkagainsteach
othertomaintainbalance
–  Ex:AirCondi&oning
ComparetoPosi&veFeedback:
Posi2vefeedback=aprocessinwhichthe
outcomemagnifiesorperpetuatesthe
process
•  Examples:
–  Contrac&onsleadingtochildbirth
–  Bloodclo\ng
Howdoesthebodymaintainhomeostasis?
Example:BodyTemperature:
Prac&ce:
Youareonalonghikeandkeep
swea&ng.
àHowdoesthisdisrupthomeostasis?
àWhatwillyourbodydotorestore
homeostasis?
àShowthisasnega&vefeedbackloop:
Prac&ce:
Youareinfectedbyabacteriathat
givesyouthestomachflu.
àHowhashomeostasisbeendisrupted?
àWhatwillyourimmunesystemdoto
maintainhomeostasis?
àHowisthisafeedbackloop?
Prac&ce:
Whenyoueat,yourbodydigestsfoodandreleases
thesugarsintoyourbloodstream,soitmaytravel
toyourcellsandsupplythemwithenergy.
àHowhashomeostasisbeen
disrupted?
àWhatwillyourendocrinesystem
dotomaintainhomeostasis?
àHowisthisafeedbackloop?
Closing:
Whatorgansystemdoeseachpicturerepresent?
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
Circulatory
Respiratory
Immune
Nervous
Lympha&c
Endocrine
Diges&ve
Excretory
Skeletal
Muscular
2.
1.
4.
3.
5.
Watch:
BodyStory,Episode2:BreakingDown
(DiscoveryChannel)
hLps://www.youtube.com/watch?v=65U3NSDn2dg
Startat25:00minutesforBob’sStory
Asyouwatch,iden2fy5specificwaysinwhich
homeostasisisdisruptedinBob’sbodyand
howhisbodytriestorestoreit.
Closing:
Whathappenstoanorganismwhen
itcannotmaintainhomeostasis?
Pleaseusescien&ficvocabularyandgiveatleast
3specificexamplesfromthevideo.
Homework:
Pleasewatchthefirsthalfofthesameepisode
(abouthowbrokenbonesarerepaired).
BodyStory,Episode2:BreakingDown
(DiscoveryChannel)
hLps://www.youtube.com/watch?v=65U3NSDn2dg
Startatthebeginningandwatchthefirst25
minutes