the human body: an orientation. figure 1.2f organ system overview cardiovascular cardiovascular...

The The Human Human

Body: An Body: An OrientatioOrientatio

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Figure 1.2f

Organ System OverviewOrgan System Overview

CardiovascularCardiovascular– Transports materials in bodyTransports materials in body

via blood pumped by heartvia blood pumped by heart OxygenOxygen Carbon dioxideCarbon dioxide NutrientsNutrients WastesWastes

Organ System OverviewOrgan System Overview

LymphaticLymphatic– Returns fluids to blood Returns fluids to blood

vesselsvessels– Cleanses the bloodCleanses the blood– Involved in immunityInvolved in immunity

Figure 1.2g

Organ System OverviewOrgan System Overview

RespiratoryRespiratory– Keeps blood supplied Keeps blood supplied

with oxygenwith oxygen– Removes carbon Removes carbon

dioxidedioxide

Figure 1.2h

Organ System OverviewOrgan System Overview

DigestiveDigestive– Breaks down foodBreaks down food– Allows for nutrient Allows for nutrient

absorption into bloodabsorption into blood– Eliminates Eliminates

indigestible materialindigestible material

Figure 1.2i

Organ System OverviewOrgan System Overview

UrinaryUrinary– Eliminates nitrogenous Eliminates nitrogenous

wasteswastes– Maintains acid-base Maintains acid-base

balancebalance– Regulates water and Regulates water and

electrolyteselectrolytes

Figure 1.2j

Organ System OverviewOrgan System Overview ReproductiveReproductive

– Produces Produces offspringoffspring

Figure 1.2k–l

Necessary Life FunctionsNecessary Life Functions

Maintain boundariesMaintain boundaries MovementMovement

– LocomotionLocomotion– Movement of substancesMovement of substances

ResponsivenessResponsiveness– Ability to sense changes and reactAbility to sense changes and react

DigestionDigestion– Break-down and absorption of nutrientsBreak-down and absorption of nutrients

Necessary Life FunctionsNecessary Life Functions

Metabolism—chemical reactions Metabolism—chemical reactions within the bodywithin the body– Produces energyProduces energy– Makes body structuresMakes body structures

ExcretionExcretion– Eliminates waste from metabolic Eliminates waste from metabolic

reactionsreactions

Necessary Life FunctionsNecessary Life Functions

ReproductionReproduction– Produces future generationProduces future generation

GrowthGrowth– Increases cell size and number of cellsIncreases cell size and number of cells

Survival NeedsSurvival Needs

NutrientsNutrients– Chemicals for energy and cell buildingChemicals for energy and cell building– Includes carbohydrates, proteins, lipids, Includes carbohydrates, proteins, lipids,

vitamins, and mineralsvitamins, and minerals OxygenOxygen

– Required for chemical reactionsRequired for chemical reactions

Survival NeedsSurvival Needs

WaterWater– 60–80% of body weight60–80% of body weight– Provides for metabolic reactionProvides for metabolic reaction

Stable body temperatureStable body temperature Atmospheric pressure Atmospheric pressure

– Must be appropriateMust be appropriate

Interrelationships Among Interrelationships Among Body SystemsBody Systems

Figure 1.3

HomeostasisHomeostasis

Homeostasis—maintenance of a Homeostasis—maintenance of a stable internal environment stable internal environment – A dynamic state of equilibriumA dynamic state of equilibrium

Homeostasis is necessary for normal Homeostasis is necessary for normal body functioning and to sustain lifebody functioning and to sustain life

Homeostatic imbalanceHomeostatic imbalance– A disturbance in homeostasis resulting A disturbance in homeostasis resulting

in diseasein disease

Figure 1.4

Changedetectedby receptor

Stimulus:Produceschangein variable

Input:Informationsent alongafferentpathway to

Receptor (sensor) Effector

Variable(in homeostasis)

Response ofeffector feedsback toinfluencemagnitude ofstimulus andreturns variableto homeostasis

Controlcenter

Imbalance

Imbalance

Output:Information sentalong efferentpathway to activate

Maintaining HomeostasisMaintaining Homeostasis

The body communicates through The body communicates through neural and hormonal control systemsneural and hormonal control systems– ReceptorReceptor

Responds to changes in the environment Responds to changes in the environment (stimuli)(stimuli)

Sends information to control centerSends information to control center

Maintaining HomeostasisMaintaining Homeostasis

– Control centerControl center Determines set pointDetermines set point Analyzes informationAnalyzes information Determines appropriate responseDetermines appropriate response

– EffectorEffector Provides a means for response to the Provides a means for response to the

stimulusstimulus

Feedback MechanismsFeedback Mechanisms

Negative feedbackNegative feedback– Includes most homeostatic control Includes most homeostatic control

mechanismsmechanisms– Shuts off the original stimulus, or Shuts off the original stimulus, or

reduces its intensityreduces its intensity– Works like a household thermostatWorks like a household thermostat

Feedback MechanismsFeedback Mechanisms

Positive feedbackPositive feedback– Increases the original stimulus to push Increases the original stimulus to push

the variable fartherthe variable farther– In the body this only occurs in blood In the body this only occurs in blood

clotting and during the birth of a babyclotting and during the birth of a baby