Download Lesson 7

Grade 10 Applied Science – Unit Human Systems
Respiratory System
Task

Identify the parts of the Respiratory System
The respiratory system supplies your blood with oxygen through breathing. During respiration,
you inhale oxygen (O2) and exhale carbon dioxide (CO2).

During inhalation, air passes through your mouth and nose into your trachea (wind pipe).
The trachea splits into two main branches called bronchi. One branch goes to the left
lung while the other to the right lung. Once there, each bronchus (singular for bronchi)
branches into smaller and smaller tubes called bronchioles. Bronchioles end in sacs
called alveoli. Each alveolus (singular for alveoli) is covered in a net of tiny blood vessels
called capillaries. Between the alveoli and the capillaries is where respiration takes
place.

The LUNGS are the major organ of the respiratory system. Lungs are filled with air
spaces. They are designed so large amounts of the membrane that lines the lungs are
exposed to the air we inhale. The lungs have a total surface area about 25X greater than
the total surface area of our skin.

The respiratory passages are lined with MUCOUS MEMBRANES that warm and moisten
the air, and at the same time, filter out dust, pollen and bacteria. The moist surface aids
in the diffusion of oxygen through the cell membranes and into the blood system.

To increase surface area, the lungs have air sacs called ALVEOLI. Adult humans have
300 million alveoli with a total surface area about the size of half a tennis court.

The TOTAL LUNG VOLUME is about six litres. Yet, we can only exhale a maximum of
five litres. This is called VITAL CAPACITY. The one litre of air remaining in the lungs is
called the RESIDUAL VOLUME
Diagram Answers
The four major organs of the respiratory system are:
 ___________________
 ___________________
 ___________________
 ___________________
In the respiratory system diagram, label the
following parts.
 nose
 mouth
 larynx
 pharynx
 bronchus
 trachea
 lung
 bronchioles
 diaphragm
 alveoli
Gas Exchange
Gases are exchanged across the alveolar walls by diffusion because the __________ levels in
the lungs are greater than in the blood and the ____________, while the _____________ levels
in the blood are greater than in the lungs.
Breathing
The breathing process involves alternatively
drawing air into the lungs and then pushing it out.
Using the diagram, describe how breathing and gas
exchange are accomplished. That is, what does the
diaphragm do? How do differences in gas pressure
inside and outside the body aid in reducing energy
use during breathing?
Breathing is controlled the brain. Explain
(HINT: Recall our conversation about CO2 levels)
What causes most respiratory diseases?
Task

Using the material and equipment supplied, build a lung. How does it work? Explain