BODY SYSTEMS

The Human Body-Levels of Structural OrganizationOrgan System Overview

Integumentary (skin)Forms the external body

coveringProtects deeper tissue from

injuryHelps regulate body temperatureLocation of cutaneous nerve receptors

Skeletal

Protects and supportsbody organs

Provides muscleattachment for movement

Site of blood cellformation

Stores minerals

Muscular

Produces movementMaintains postureProduces heat

Nervous

Fast-acting controlsystem

Responds to internal andexternal change

Activates muscles andglands

Endocrine

Secretes regulatoryhormones

GrowthReproductionMetabolism

Cardiovascular

Transports materials in bodyvia blood pumped by heart

OxygenCarbon dioxideNutrientsWastes

Lymphatic

Returns fluids to blood vesselsCleanses the bloodInvolved in immunity

Respiratory

Keeps blood supplied with oxygenRemoves carbon dioxide

Digestive

Breaks down foodAllows for nutrient absorption into bloodEliminates indigestible material

Urinary

Eliminates nitrogenous wastesMaintains acid-base balanceRegulates water and electrolytes

Reproductive

Produces offspring

Necessary Life FunctionsMaintain boundariesMovementLocomotionMovement of substancesResponsivenessAbility to sense changes and reactDigestionBreak-down and absorption of nutrients

Necessary Life FunctionsMetabolism—chemical reactions within

the bodyProduces energyMakes body structuresExcretionEliminates waste from metabolic

Necessary Life FunctionsReproductionProduces future generationGrowthIncreases cell size and number of cells

Needed for survivalNutrientsChemicals for energy and cell buildingIncludes carbohydrates, proteins, lipids,

vitamins, and mineralsOxygenRequired for chemical reactionsWater60–80% of body weightProvides for metabolic reactionStable body temperatureAtmospheric pressure Must be appropriate

Interrelationships Among Body SystemsHomeostasis—maintenance of a stable

internal environment A dynamic state of equilibriumHomeostasis is necessary for normal

body functioning and to sustain lifeHomeostatic imbalanceA disturbance in homeostasis resulting

in disease

HomeostasisHomeostasis—maintenance of a stable

internal environment A dynamic state of equilibriumHomeostasis is necessary for normal

body functioning and to sustain lifeHomeostatic imbalanceA disturbance in homeostasis resulting

in disease

Homeostasis cont:The body communicates through neural

and hormonal control systemsReceptorResponds to changes in the environment

(stimuli)Sends information to control center

Homeostasis cont:Control centerDetermines set pointAnalyzes informationDetermines appropriate responseEffectorProvides a means for response to the

stimulus

Feedback MechanismNegative feedbackIncludes most homeostatic control

mechanismsShuts off the original stimulus, or reduces

its intensityWorks like a household thermostatPositive feedbackIncreases the original stimulus to push the

variable fartherIn the body this only occurs in blood clotting

and during the birth of a baby