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Lesson Overview
The Respiratory System
Objectives 33.3
The Respiratory
System
-Identify the structures of the
respiratory system and describe
their functions.
-Describe gas exchange.
-Describe how breathing is
controlled.
-Describe the effects of smoking on
the respiratory system.
Lesson Overview
The Respiratory System
vocab
Word
Definition
Pharynx
Tube at the back of the mouth that serves as a passageway for both
air and food, also called throat
Trachea
Tube that connects the larynx to the bronchi, also called the
windpipe
Larynx
Structure in the throat that contains the vocal cords
Bronchus
One of two large tubes in the chest cavity that leads from the
trachea to the lungs
Alveolus
One of many tiny air sacs at the end of a bronchiole in the lungs
that provides surface area for gas exchange to occur
diaphragm
Large flat muscle at the bottom of the chest cavity that helps with
breathing
Lesson Overview
The Respiratory System
Structures of the Respiratory System
The respiratory system
consists of the nose,
pharynx, larynx,
trachea, bronchi and
lungs.
Lesson Overview
The Respiratory System
Nose
To keep lung tissue healthy, air entering the respiratory system must be
filtered, moistened, and warmed; this all happens in the nasal cavity or
nose.
Hairs lining the entrance to the nasal cavity filter and trap large particles.
Lesson Overview
The Respiratory System
Pharynx and Trachea
Air moves through the nose to a cavity at the back of the mouth called the
pharynx.
Air moves from the pharynx into the trachea, or windpipe.
A flap of tissue called the epiglottis covers the entrance to the trachea.
Lesson Overview
The Respiratory System
Larynx
Between the pharynx and the trachea is the larynx, which
contains two highly elastic folds of tissue known as the vocal
cords.
Lesson Overview
The Respiratory System
Trachea
Mucus produced in the trachea
continues to trap inhaled
particles.
Cilia lining the trachea sweep
both mucus and trapped
particles away from the lungs
toward the pharynx, where they
can be swallowed or spit out.
Lesson Overview
The Respiratory System
Lungs
From the trachea, air moves
into two large tubes called
bronchi. Each bronchus
leads to one lung.
Within each lung, the large
bronchus divides into
smaller passageways called
bronchioles.
Lesson Overview
The Respiratory System
Lungs
The bronchioles
continue to divide until
they end at a series of
tiny air sacs called
alveoli.
A network of capillaries
surrounds each
alveolus.
Lesson Overview
The Respiratory System
Gas Exchange
Gas exchange happens at the
alveoli in the lungs by diffusing
across the thin capillary walls
into the blood.
Lesson Overview
The Respiratory System
Smoking
Three of the most dangerous substances in
tobacco smoke are nicotine, carbon
monoxide and tar.
Nicotine is an addictive stimulant that
increases heart rate and blood pressure.
Carbon monoxide is a poisonous gas that
blocks hemoglobin from binding with oxygen.
Tar contains at least 60 compounds known
to cause cancer.
Lesson Overview
The Respiratory System
Effects on the Respiratory System
Tobacco smoke paralyzes cilia
in the trachea, allowing inhaled
particles to stick to enter the
lungs.
Lesson Overview
The Respiratory System
Diseases Caused by Smoking
Chronic Bronchitis ~ In chronic bronchitis, the bronchi become
inflamed and clogged with mucus.
Emphysema ~ Long-term smoking can lead to emphysema, the loss of
elasticity and eventual breakdown of lung tissue.
Lung Cancer ~ Lung cancer is particularly deadly because, by the time
it is detected, it usually has spread to other areas of the body.