Topic: Respiratory System
Aim: Describe the processes of gas
exchange and breathing.
Do Now: Describe the path of air when you
inhale.
HW:
nose
mouth
pharynx
larynx
trachea
lung
bronchi
bronchi
bronchioles
diaphragm
alveoli
Did you know…
• Your lungs contain almost 1500 miles
of airways and over 300 million alveoli.
• During normal breathing, the speed
that you exhale air is about 4 miles per
hour.
• Plants are our partners in breathing.
We breathe in air, use the oxygen in it,
and release carbon dioxide. Plants take
in carbon dioxide and release oxygen.
Gas exchange
a. Alveoli fill up O2
b. O2 diffuses into capillaries
c. CO2 & H2O vapor diffuses out
of capillaries into alveoli
Inside of alveolus
CO2
O2
Diaphragm
• Sheet of
muscle
under lungs
• Aids in
breathing
When your diaphragm becomes irritated, it pulls
down in a jerky way, which makes you suck air into
your throat suddenly. When the air rushing in hits
your voice box, you're left with a big hiccup. Some
things that irritate the diaphragm are eating too
quickly or too much, excessive laughing, an irritation
in the stomach or the throat, or feeling nervous or
excited (breathing fast).
Breathing • Inhalation  air
travels INTO lungs
• Exhalation  air
pushed OUT OF lungs
• Involves the
diaphragm & rib cage
muscles
Inhalation
• Diaphragm moves DOWN
(contracts)
• Rib cage expands
• Less pressure
• Air rushes in
Exhalation
• Diaphragm moves UP
(relaxes)
• Rib cage relaxes
• More pressure
• Air forced out
Maindex
REMEMBER…
Inhale DOWN
Exhale UP
What
controls
breathing
rate?
• Brain  MEDULLA
–Detects the level of CO2 in
the blood
Let’s summarize…:
1. Where does gas exchange occur?
2. Describe the process of gas exchange.
3. Which way does the diaphragm move
during inhalation? During exhalation?
4. What happens to pressure in the chest
cavity during inhalation? During
exhalation?
5. Which gas regulates breathing rate?
http://www.youtube.com/watch?v=6NXaHGuRMsc&feature=related
BELL JAR MODEL OF THE RESPIRATORY SYSTEM
1
2
3
4
1 = TRACHEA
2 = BRONCHI
3 = ALVEOLI
4 = DIAPHRAGM
BELL JAR MODEL OF THE RESPIRATORY SYSTEM
EXHALATION
INHALATION
BELL JAR MODEL OF THE RESPIRATORY SYSTEM
EXHALATION
Diaphragm moves UP
Pressure increases
Air forced up & out
INHALATION
Diaphragm moves DOWN
Pressure decreases
Air enters