IntroductiontoPhysiologyHOMEOSTASISPhysiologyUnit1

InPhysiologyToday

• Welcometophysiology!• Goovercoursesyllabusandoutlineinlab• StemCenter61-3318• ChemistryTestWednesday

• Bringascantron

• Introductiontophysiology• Homeostasis

NewCoursesBeingOffered

• Pub24:IntrotoPublicHealth• Online• 8weekcourse(weeks1-8)

• Pub29: PublicHealthMicrobiology• Online• 8weekcourse(weeks9-16)

• Anat38:Pathophysiology• Summer2019• Online

• PUB20:HistoryofWesternMedicine• Summer2019• Online

PUBLIC HEALTH “QUICKIES”!

PUBH 24 — 8 weeks, online Introduction to Public Health…this is the “gateway” course for all public health courses! Offered the first 8 weeks of spring semester!

PUBH 29 — 8 weeks, online Public Health Microbiology…this course gives you an opportunity to explore microbiology from a public health perspective. Issues of food safety, water quality, controlling chronic diseases and preventing the spread of infectious diseases in populations will be covered. PUBH 24 & Micro 1or 22 prerequisites! Offered second 8 weeks of spring semester!

COMING SPRING 2019

FOR MORE INFORMATION ON A.S. DEGREE IN PUBLIC HEALTH

CONTACT DR. CARMEN E. REXACH, CREXACH@MTSAC.EDU

WhatisLife?CharacteristicsofLife• Maintainingboundaries• Movement• Responsivenesstostimuli• Digestion• Metabolism• Excretion• Reproduction• GrowthandDevelopment• Homeostasis

BasicRequirements

• Oxygen• RequiredtomakeATP• WhereisO2 usedinthebody?

• Water• WhydoweneedH20?

• Nutrients• FuelsourcestomakeATP

• Processestomaintainhomeostasis

BodyWaterCompartments

• Themajorityofourbodycompositioniswater• Adults≈60%water• 42Lofwater• Internalenvironment

• Intracellularfluid• 28L

• ExtracellularFluid• Interstitialfluid

• 11L• Plasma

• 3L

Homeostasis

• Maintainingarelativelyconstantinternalenvironment,despitefluctuationsintheexternalenvironment,tosustainnormalphysiologicalactivity

Requirestheexpenditureofenergy

HomeostaticControlMechanisms• Stimulus• Detectablechangeininternalorexternalenvironmentfromthesetpointoroperatingpoint

• Reflexes• Specific,involuntaryresponsetospecificstimulus

• FeedbackLoop• Pathwayofreflex• Components

• Sensoryreceptor• Integratingcenter• Effector

Controlledbychemicalmessengers

NegativeFeedbackLoops

• Movesintheoppositedirectiontowardtheoriginalvalue• Inhibitorysignals• Reestablishingthesetpointinhibitstheresponse• Examples

• Bodytemperatureregulation• Hormonebalance

PositiveFeedbackLoops

•Movesinthesamedirectionastheinitialdisturbance• Buildingeffect• Stimulatorysignals• Examples• clottingcascade• labor• heatstroke

Fever:ResettingtheSetPoint• Roleofhypothalamus• Controlledhyperthermia• 1-2oC(1.8-3.6oF)

• ReleaseofpyrogensfromWBC’s,damagedtissues,macrophage• Increasedreleaseofprostaglandins(chemicalmessengers)resethypothalamus• Newsetpointistemporarilymaintained• Inducingheatgeneratingmechanisms

• Increasedmuscletone• Shivering• Epinephrine

• Mechanismsforpreventingheatloss• Vasoconstriction=chills

Farenheit to Celcius (oF – 32) * 5/9

FeedForwardRegulation

• Anticipateschanges• Minimizesfluctuationsinvariable• Ensuresrapidresponsetochange• Reducesamountofdeviationfromsetpoint

• Examples• Effectofsightandsmelloffoodondigestion• Circadianrhythms

LocalHomeostaticResponses

• Changestimulatesalterationincellularactivityinonespecificarea• Results:self-regulationinspecificareaofbody

BiologicalRhythms

• Circadianrhythms(24hourcycles)• Activateshomeostaticmechanismswhenchangelikelytooccur• Internallydriven(e.g.pinealgland– melatonin)• Anticipatory=feedforward

• Types• Freerunningrhythms

• Sleep/wakecycles=23-27hours• Stablerhythmcannotbeestablishedbythosewhoworklongerhours

• Phaseshiftrhythms• Environmentaltimecuescanresetinternalclock(travel)• Adjustmentisnotimmediate=jetlag

CircadianRhythms