First&things&first…& Why&study&science?

Why&study&biology?&

• h"ps://www.youtube.com/watch?v=2pp17E4E:O8&t=10s?

Expecta;ons

Be#present#in#class#•  I?am?present?in?class?and?engage?with?others?and?the?material.??•  I?use?technology?responsibly?and?as?a?tool?in?the?classroom?Be#respec-ul#of#the#learning#community#•  I?am?an?acGve?listener?and?engage?in?conversaGons?in?a?non:judgmental?manner?and?respect?the?learners?around?me.??

Come#to#class#with#an#open#mind#and#try#your#best##•  I?come?to?class?prepared?and?ready?to?learn??

?

Homeostasis&Ac;vity!!&

h"ps://www.youtube.com/watch?v=6B9J3lEyffA??

Learning&Inten;ons

•  I?understand?that?the?body?has?feedback?mechanisms?to?maintain?homeostasis?

•  I?can?explain?both?posiGve?and?negaGve?feedback?loops?and?provide?an?example?of?each.??

???Slides?completed?by?Jen?Kong??

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Anatomy,&Physiology,&&&Pathophysiology

• Anatomy?=?Describes?the?structures?of?the?body?• What?they?are?made?of?• Where?they?are?located?•  Associated?structures?

•  ?Physiology?=?Is?the?study?of:?•  Func:ons?of?anatomical?structures?•  Individual?and?cooperaGve?func:ons#

• Pathophysiology?=?when?our?physiological?symptoms?are?not?working?the?way?they?are?supposed?to.?

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Homeostasis

=?The?maintenance?of?body?systems?in?a?state?of?balance?and?equilibrium?

• Homeostasis?ensures?that?the?internal?environment?remains?steady?despite?changes?externally?via?FEEDBACK?mechanism?

FEEDBACK&SYSTEMS •  3?basic?components:??•  Receptor:?structure?that?monitors?changes?in?a?controlled?condiGon;?sends?info.?to?control?center?

•  Control?center:?receives?informaGon?and?sends?output?(via?nerve?impulses?or?chemical?signals)?to?effectors?

•  Effector:?structure?that?receives?output?and?produces?a?response?that?changes?the?controlled?condiGon?

•  Two?types:??negaGve?&?posiGve?

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Feedback Systems Nega:ve#Feedback#•  The?response?of?the?effector?negates?the?s:mulus?

• Body?is?brought?back?into?homeostasis?

• Normal#range?is?achieved??• NegaGve?feedback?control?leads?to?STABILITY#

•  Example:??sweaGng,?shivering?

Posi:ve#Feedback#•  The?response?of?the?effector?increases/?reinforces?change?of?the?s:mulus##

•  Body?is?moved?away?from?homeostasis?=?Normal#range?is?lost?

•  Used?to?speed?up?processes??•  Leads to INSTABILITY because the

output becomes progressively stronger as it is fed back and re-amplified.

•  Examples: clotting cascade, labour & delivery

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Example&of&posi;ve&feedback:&&Story&of&being&a&Doula&

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Disease • Failure of

body systems to function within a “normal” range results in disease

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Tolerance • Range of tolerance - range of a specific

environmental variable that an individual can survive

•  i.e. compensatory mechanisms maintain the system in a dynamic steady state

• Tolerance to specific disturbances is influenced by genetic make-up of individual

• above and below the critical values are ranges beyond tolerance which an individual will eventually die

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Summary so far • Anatomy = structure; Physiology = function • Pathophysiology = disordered function • Homeostasis is a state of equilibrium that

needs work to restore balance •  Negative feedback negates the stimulus •  Positive feedback reinforces the stimulus

•  Gets everything finished with quicker •  Genetically determined tolerance range

• Failure results in pathophysiology, disease or death

Building&Posi;ve&and&Nega;ve&Feedback&Loops&& Task:?Research?a?feedback?mechanism?(Does?not?need?to?be?found?in?humans).??Complete?the?following:?•  ?Design?a?model?or?diagram?or?write?a?short?summary?about?this?mechanism.??•  Explain?if?it?is?a?posiGve?or?negaGve?feedback?loop??•  Explain?why?this?mechanism?is?important?????To?get?started?you?may?want?to?consider?thinking?about?the?following?quesGons:??•  What?happens?when?you?are?cold??What?happens?when?you?are?hot??•  What?happens?when?you?don’t?drink?enough?water??What?about?when?you?drink?to?much?water??What?organ?system?may?be?involved?in?regulaGon?of?water?balance??

?•  Take?image?of?your?final?produce?and?upload?to?fresh?grade?as?part?of?your?porfolio?and?include?your?wri"en?explanaGon?in?the?comment?secGon.??

Take&Away&Tasks

1.?Complete?Building?PosiGve?and?NegaGve?Feedback?Assignment??2.?Review?Basic?Chemistry:?by?watchingh"ps://www.youtube.com/watch?v=h6LPAwAmnCQ???•  There?will?be?a?quiz?based?on?the?video?next?class?

• Note,?if?you?would?like?to?do?an?extra?assignment?to?improve?cell?structure?and?funcGon?test?mark,?you?can?come?talk?to?me.?Test?marks?are?posted?on?freshgrade.??