13-1 the respiratory system web

8/9/2019 13-1 the Respiratory System Web

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Respiration andExcretion

Chapter 13


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The Respiratory

SystemChapter 13 Section 1


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The Respiratory

SystemThe respiratory system functions to

move oxygen from the outsideenvironment into the body

It also removes carbon dioxide andwater from the body


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Why the Body

Needs OxygenEnergy releasing chemical reactionsinside the body require oxygen

Respiration- the process in whichoxygen and glucose undergo acomplex series of chemicalreactions inside cells

These chemical reactions release

energy that fuels growth andcellular processes

The body releases carbon dioxideand some water through the lungs


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The Path of AirAir travels from the outsideenvironment to the lungs, it passesthrough the nose, pharynx,

trachea, and bronchiThe structures of these organs

enable them to warm and moistenair and to remove harmfulmaterials


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The NoseAir travels through thenostrils into the nasalcavities

The lining of the nasalcavities contains many

blood vessels that heat theair

Cells lining the cavitiesproduce mucus thatmoistens the air and trapsmany particles such as dust

and bacteria

Cilia- tiny hair-like extensionsthat line the nasal cavitiesthat move together likewhips to sweep the mucusinto the throat, where you

swallow it.


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The Path Continues The Pharynx

After leaving thenasal cavities,

air enters thepharynx, orthroat

Pharynx is theonly part of the

respiratorysystem that isshared with thedigestive system

The Trachea

From the pharynx, air moves into the trachea,or windpipe.

The trachea is surrounded by rings of cartilagethat strengthen and keep it open

The trachea is lined with cilia and mucus

Cilia sweep upward, moving mucus toward thepharynx to be swallowed

If the trachea is irritated, you cough


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e ronc anLungs

Air moves from the trachea to thebronchi

Bronchi are the passages that directair into the lungs

Lungs are the main organs of therespiratory system

At the end of the smallest tubes arealveoli

Alveoli-tiny sacs of lung tissue whostructure is specialized for themovement of gases between air andblood

Alveoli are surrounded by capillaries

that pick up oxygen from the air


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Function in Gas

ExchangeAfter air enters analveolus, oxygenpasses through the wallof the alveolus and

then through thecapillary wall into theblood.

Carbon dioxide and

water pass from theblood into the alveoli

Alveoli have a hugesurface area enablingthem to absorb largeamounts of oxygen


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How You Breathe

Breathing is controlled by muscles and surrounded by the ribs

Diaphragm- a large, dome-shaped muscle that plays an importantrole in breathing

When you breathe in, the rib muscles contract, lifting the chestwall upward and outward.

The diaphragm contracts and moves downward.

This makes the chest cavity larger, providing extra space for thelungs to expand

For a moment there is no extra air to fill the space; the sameamount of air now occupies a larger space & the air pressureinside the lungs decreases

The pressure of air inside the chest cavity is lower than theatmosphere, therefore air rushes into your chest


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How You SpeakLarynx- voice box located at the top part of thetrachea beneath the epiglottis

Vocal chords- strands of connective tissue that

stretch across the larynx and produce the voiceWhen you speak, muscles make the vocal chordscontract, narrowing the opening

Air from the lungs vibrates as it moves past thechords and produces sound

When vocal chords contract and shorten, your voicebecomes higher

Vocal chords that lengthen and relax produce alower voice


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ReviewList the functions of the respiratory system.

How does the structure of the nose enable it to warm andmoisten air and remove particles?

Explain what happens to carbon dioxide in the blood that flows

through capillaries in the alveoli.

Why does air rush into your body when you inhale?

When there is a lot of dust in the air, people often cough andsneeze. Why?

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