10-1 organization and homeostasis web version

8/14/2019 10-1 Organization and Homeostasis Web Version

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Bones, Muscles,and Skin

Chapter 10


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Organization andHomeostasis

Chapter 10 Section 1


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Levels ofOrganization

The levels of organization in complexorganisms, including most plants andanimals, consist of cells, tissues,

organs, and organ systemsSmallest unit of organization is the cell,

and the largest is the organ system


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Cells: Structure andFunction

Cell- the basic unit of structure andfunction in a living thing

Structure- an organisms body plan, or theway its parts are arranged

Function- part of an organisms job, or theprocess it carries out

Cell membrane- forms outside boundary ofthe cell

Nucleus- control center that directs thecells activities and contains informationthat determines the cells characteristics

Cytoplasm- Area between the cell

membrane and the nucleus Cytoplasm contains a clear, jellylikesubstance in which many important cellstructures, called organelles are found

Cells contain molecules from digested foodthat provide energy and they get rid ofwaste products, grow, and reproduce


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TissuesTissue is the next largest unit or

organization in complex organismsTissue- a group of similar cells that

perform the same functionAnimals body contains contains four

basic types of tissue: muscle tissue,nerve tissue, connective tissue, andepithelial tissue


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TissuesMuscle tissue can contract and shorten

functioning to make parts of the bodymove

Nerve Tissue- directs and controls

movementNerve tissue carries messages back and

forth between the brain and every otherpart of the body

The brain is made up of mostly nerve tissueConnective tissue-provides support for thebody and connects all its parts; bone, fat

Epithelial tissue- covers the surfaces of theoutermost layer of the skin, protects

delicate structures that lie beneath it

O d O


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Organs and OrganSystems

Organ- a structure that is composed of differentkinds of tissue

Stomach, heart, brain, and lungs are organsOrgans have a specific functionEach organ is part of an organ system

Circulatory systemDigestive systemEndocrine systemExcretory system Immune systemMuscular system

Nervous systemReproductiveRespiratorySkeletal SystemSkin


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Maintaining Stable

Internal ConditionsThe organ systems in an organism worktogether to maintain homeostasis, thebodys tendency to keep an internal

balanceHomeostasis- the process by which an

organisms internal environment is keptin equilibrium, or stable, in spite of

changes in the external environmentAll organisms have ways of regulating

the amount of water inside them


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H

om

eo

stasi s

Maintaining Temperature

The body maintains aconstanttemperaturewhether you are ina blizzard or anoverheated room

The body maintains

an averagetemperature of98.6F

Sickness may causethe bodystemperature to rise

Perspiration is the

bodys response toenvironmentalconditions tomaintain a stablebody temperature

The sweat cools thebody

Responding to stimuli

Stimulus-something inside

or outside anorganisms body

that causes theorganism to react

in some way Response- action or

change inbehavior that

occurs as the

result of astimulus

Hunger is an

internal stimulus Food is an external

stimulus Eatin food is the


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Stress

and

H

om

eo

st a

si s

Physical Responses to

stress

Stress- the reactionof your body and

mind tothreatening,

challenging, ordisturbing events

Stress upsetshomeostasis

The body releases achemical called

adrenaline into

your bloodstream Adrenaline acts as

an internal

stimulus thatgives the body a

burst of energy

Fight or flight

Reactions caused byadrenaline are

sometimes calledthe fight-or-

flight response,because they

prepare you toeither fight the

stressor or to takeflight and escape

Body systems work

together torespond to thestressor


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Long-Term StressAfter the stress is over quickly, the body

regains homeostasisWhen a stressful situation does not go

away, your body cannot restorehomeostasis


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ReviewList the four levels of organization in

organisms. Give an example of each level.

Name the four types of tissue in animals.Give an example of where each is located.

What is homeostasis?

Describe what happens during the alarmstage of stress.

What systems of your body are involvedwhen you make a sandwich and then eatit?

Skeletal, nervous, muscular, circulatory,

and digestive systems

10-1 organization and homeostasis web version

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