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Take in oxygen
Get rid of carbon dioxide
Helps with smelling
Filters air that is inhaled
Produces sounds
Rids the body of some water and heat in
exhaled air
The organs of the respiratory system include the
nose, pharynx, larynx, trachea, bronchi,
bronchioles, alveoli and lungs.
Nose:
• The 2 external openings are called external
nares.
• The internal portion of the nose has 2 openings
that connect to the throat called internal nares
• The nose is divided into right and left internal
parts by the septum.
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Coarse hairs in the nose filter out large dust
particles
Nasal conchae- 3 shelves that extend out of
the wall of the nasal cavity to increase
surface area for warming, moistening and
filtering.
Mucous membranes line the nasal cavity
and secrete mucus that moistens the air and
traps dust particles.
Above the conchae is the olfactory
epithelium which detects smells.
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Pharynx is also called the throat- A tube that starts
at the internal nares and extends part way down
the neck.
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A passageway for air and food and provides a
resonating chamber for speech sounds.
Larynx is the voice box. It is a short passageway
that connects the pharynx with the trachea.
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Thyroid cartilage (Adam’s apple) forms the anterior
wall of the larynx
Epiglottis is elastic cartilage that is the top part of the
larynx. It prevents food and drink from entering the
larynx.
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The mucous membrane of the larynx forms 2 pairs
of folds: false vocal cords and true vocal cords.
True vocal cords produce sound. They are elastic
ligaments that are stretched between pieces of
cartilage. They are also attached to muscles that
pull the ligaments tightly when contracted. This
moves the true vocal cords out into the air
passageway. Air pushed against the cords causes
them to vibrate and produce sound waves.
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Males have thicker vocal cords due to male sex
hormones. These vibrate more slowly and produce a
deeper pitch.
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Windpipe- Air passageway anterior to the
esophagus
Extends from the larynx to the 5th thoracic
vertebra
Wall is lined with a mucous membrane
Cilia also line the wall and help move mucus
up the trachea
Supported by cartilage- 16 to 20 C-shaped rings
that are stacked on top of another.
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Heimlich maneuver may be used to expel
an aspirated object.
If not successful, a tracheostomy may be
performed- incision in the trachea below
the cartilage and a tube is inserted.
Intubation is another method when a
tube is inserted into the mouth or nose
and passed down through the larynx and
trachea.
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Bronchi are branches of the trachea that each
feed a lung.
The right bronchus is more vertical, shorter
and wider than the left. As a result, foreign
objects are more likely to enter and lodge in the
right bronchus than in the left.
Bronchi contain C-rings of cartilage and are
lined with cilia.
Bronchi branch into smaller bronchioles, which
do not contain cartilage rings but are lined with
more smooth muscle for support.
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Asthma is chronic airway inflammation due to
hypersensitivity to a variety of stimuli. These
triggers include allergens, emotional upset,
exercise, breathing cold air and cigarette
smoke.
Triggers cause the walls of the bronchi and
bronchioles to spasm, the mucous membranes
to swell, increased mucus secretion or damage
to the lining of an airway.
Asthma symptoms include difficulty breathing,
coughing, wheezing, chest tightness, fatigue
and anxiety.
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Lungs are covered directly with visceral pleura
and the lung cavity is lined with parietal pleura.
Pleurisy- inflammation of the pleural membranes
which causes friction during breathing which is
quite painful.
The narrow top of each lung is the apex. The
broad bottom is the base. The area on the medial
side through which bronchi enter is called the
hilus.
The right lung has 3 lobes and the left lung has 2
lobes. The left lung has a concavity where the
heart lies- called the cardiac notch.
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The airways dead-end with thin air
sacs called alveoli.
Capillaries surround the alveoli and
allow for gases to be exchanged.
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Diffusion- movement of molecules
from where there is more of them
to where there is less of them.
What do you think will happen to a drop
of food coloring placed in a beaker of
water?
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This occurs due to differences in air
pressure between the thoracic (chest)
cavity and the atmosphere.
Air always moves from where it is
under greater pressure to where it is
under less pressure.
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Draw 8 air molecules in each of the containers
below:
Which one has greater air pressure
inside?
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Inhalation (Inspiration)
Diaphragm contracts and moves down
Ribcage moves out
Air pressure in the thoracic cavity goes down
Air rushes in
Exhalation (Expiration)
Diaphragm relaxes and moves up
Ribcage moves in
Air pressure in the thoracic cavity goes up
Air rushes out
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Why do we need to breathe in oxygen?
What produces carbon dioxide?
Why do we need to get rid of carbon dioxide?
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CO is an odorless and colorless gas produced
when there is incomplete burning of natural
gas or any carbon containing fuel.
Why is it dangerous when inhaled?
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As we age, the following changes occur to the
respiratory system:
• Tissues become less elastic which results in a
decrease of lung capacity.
• There is a decrease in oxygen levels in the
blood.
• There is a decrease in the activity of alveolar
macrophages
• There is diminished ciliary action of the
respiratory tract
Because of these, elderly people are more
susceptible to pneumonia, bronchitis, and
emphysema.
1. Apneustic center
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7. Septum
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13. Thyroid cartilage
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15. Olfactory epithelium
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19. Larynx
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