introduction to physiology homeostasis...homeostasis physiology unit 1. in physiology today...
TRANSCRIPT
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, [email protected]
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