1. 8 Science
Respiratory System

2. Respiratory System

3. 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
Nose

4. 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

5. The Function of the Larynx
Also called the voice box.
Passageway for air
Sounds are made when air vibrates through the larynx
Larynx

6. 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)
Throat

7. The Function of the Trachea
“Windpipe”
Long tube leading from the nose/mouth 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.
Trachea

8. 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 or right lung
Note: right lung is on the same side as your right hand
Bronchus

9. 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

10. 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

11. The Function of the Bronchiole(s)
Carry (transport) air
They are smaller and smaller branches off the bronchi
Bronchiole(s)

12. The Structure of the Alveolus
Tiny sacs with a membrane located at the end of each bronchiole
1 alveolus; 2 alveoli (plural)
Very small blood vessels (called capillaries) surround the alveoli
Alveolus

13. 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
The respiratory system is responsible for the exchange of oxygen and carbon dioxide.
Capillaries
Copyright Pearson Prentice Hall

14. The Function of the Alveolus
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 the alveoli
These capillaries carry the carbon dioxide rich blood to the alveoli and the oxygen rich blood back to the body.
Alveolus

15. Copyright Pearson Prentice Hall
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
Gas exchange occurs by diffusion across the membrane of an alveolus and a capillary.
Capillary
Copyright Pearson Prentice Hall

16. For gas exchange Because… exchange to occur we need:
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
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

17. Breathing Movements: Inhalation
Intercostal muscles between ribs allow chest cavity to expand.
The ribs move upward and outward, the diaphragm moves downward.
Volume is increased inside chest cavity.
Pressure in lungs is decreased inside chest cavity.
Air enters lungs to equalize pressure.

18. 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.
Volume is decreased inside chest cavity.
Pressure in lungs is increased inside chest cavity.
Air is forced out.