Functions of the Respiratory System

• Brings oxygen in from the environment for our body cells, and removes carbon dioxide waste.

• Main components:– Nose– Pharynx: part of the throat behind nasal cavity and

mouth.– Larynx: voice box, houses vocal cords.– Trachea: windpipe, air travels from trachea toward

the lungs.

Respiratory System

• Components continued:– Bronchi: or bronchus (singular). The bronchi bring

air into the lungs.– Bronchioles: bronchi branch into smaller airways

that carry air to the alveoli.– Alveolus: or Alveoli (plural). Structures in the lungs

where gas exchange occurs.• Oxygen leaves the alveoli and goes into the

bloodstream to be taken to our cells.• Carbon dioxide leaves the blood and into the alveoli to

be breathed out.

Pharynx

Nose

Larynx

BronchiolesBronchus

Trachea

Alveolus

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The Lungs

• The lungs: expand and contract to bring air in and force air out of the body.

• When we bring air into the body it is called inhalation.

• When we force air out (breathe out) it is called exhalation.

• The process of breathing in and out is controlled by a muscle called the diaphragm.

Diaphragm

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Breathing

• The process of breathing is known as respiration.• When the diaphragm contracts and pulls downward

the lungs expand and pull air in.• When the diaphragm relaxes

it pushes upward and the lungs contract and push air out.

Disorders of the Respiratory System

• Lung damage can occur due because of breathing in chemicals (like pollutants, cigarette smoke, asbestos, and fumes).

• Emphysema: lung tissue damage, that causes problems breathing.– Most cases of emphysema develop in smokers, or

those exposed to second hand smoke.– Tar buildup in the lungs causes lung tissue

damage.

Review

• Air moves through the respiratory system:– Nose– Pharynx– Larynx– Trachea– Bronchi– Lungs– Bronchioles– Alveoli

• Breathing in: Inhalation• Breathing out: Exhalation

• Review Video