Transcript Respiratory System

8 Science
Respiratory System
The Function of the Nose
For smelling and
breathing.
 Allows air into and out
of the respiratory
system.
 Contains cilia to
prevent dust particles
from getting into the
system
 Warms the incoming
air
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Nose
The Function of the Mouth
Allows air in and out
when breathing.
 Doesn’t filter the air
as well as the nose
does.
 Warms the air

Mouth
The Function of the Larynx
Also called the voice
box.
 Passageway for air
 Sounds are made
when air vibrates
through the larynx
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Larynx
The Function of the Throat
Contains two
passageways.
 One is for passing
food & is called the
esophagus (food
pipe)
 One is for passing
air & is called the
trachea (wind pipe)
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Throat
The Function of the Trachea
“Windpipe”
Long tube leading
from the nose/mouth
Trachea
to the lungs
 Carries warmed air to
the lungs from the
mouth/nose
 Lined with rings of
cartilage that you can
feel when you touch
your throat.
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The Function of the Bronchus
1 bronchus on each
side of the trachea
 2 bronchi in total
(plural form is bronchi)
 bronchi pass air from
trachea to left lung orBronchus
right lung
 Note: right lung is on
the same side as your
right hand

The Function of the Diaphragm
Muscle stretching
across the abdomen
under the lungs
 Pulls air into the
lungs (when it moves
down toward your
belly button)
 Pushes air out of the
lungs (when it
relaxes or moves up)

Diaphragm
The Function of the Lungs
Main organ of the
respiratory system
 Balloon shaped, full
of sacs called alveoli
 allows exchange of
oxygen and carbon
dioxide (oxygen into
blood; carbon
dioxide out of blood)

Lung
The Function of the Bronchiole(s)
Carry (transport) air
 They are smaller and
smaller branches off
the bronchi

Bronchiole(s)
The Structure of the Alveolus
Tiny sacs with a
membrane located at
the end of each
bronchiole
 1 alveolus; 2 alveoli
(plural)
Alveolus
 Very small blood
vessels (called
capillaries) surround
the alveoli

The Human Respiratory System
Alveoli
are grouped
in clusters.
A network of
capillaries surrounds
each alveolus
Capillaries are tiny
blood vessels (pipes)
Pulmonary
artery
Pulmonary
vein
Capillaries
Copyright Pearson Prentice Hall
The Function of the Alveolus
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Gas exchange (oxygen into
the body cells and carbon
dioxide out of the body
cells) happens through
their membrane
Gases move in and out by
diffusion.
Very small blood vessels
(called capillaries) surround
Alveolus
the alveoli
These capillaries carry the
carbon dioxide rich blood to
the alveoli and the oxygen
rich blood back to the body.
Gas Exchange
RESPIRATION
○ Gas exchange takes
place in the alveoli.
○ Oxygen diffuses into the
blood.
○ Carbon dioxide in the
blood diffuses into the
alveolus.
○ Let’s examine this up
close
O2
CO2
Capillary
Copyright Pearson Prentice Hall
For gas exchange
exchange to occur
we need:
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air sacs and blood
vessels with thin
membranes
Moist (watery) surface
Concentration difference
Large surface area to
volume ratio (alveoli)
The gases must be
exchanged close to the
circulatory system
Because…
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So that oxygen and carbon
dioxide can pass through the
membranes
So that oxygen and carbon
dioxide can dissolve in the
water
Diffusion can only happen when
one area has a high
concentration and the other
area has a low concentration
More surface to trade
(exchange) gases
Circulatory system can now
move the gases to all cells in
the body
Breathing Movements: Inhalation
Intercostal
muscles
between ribs
allow chest
cavity to
expand.
The ribs move upward and outward, the
diaphragm moves downward.
2. Volume is increased inside chest cavity.
3. Pressure in lungs is decreased inside
chest cavity.
4. Air enters lungs to equalize pressure.
1.
Breathing Movements: Exhalation
Relaxation of
intercostals
allow chest and
ribs to relax.
Cavity shrinks in
size.
The ribs move inward and downward, the
diaphragm moves upward.
2. Volume is decreased inside chest cavity.
3. Pressure in lungs is increased inside chest
cavity.
4. Air is forced out.
1.