The respiratory system's main function is breathing. The lungs and trachea are the main organs that perform this function. When we eat, we get energy, but our cells need oxygen to convert food into energy. Our nose filters air before it reaches our lungs. In the lungs, bronchi tubes force air into alveoli, where oxygen passes to red blood cells and carbon dioxide is released back into the lungs.

1. Respiratory System
Biology and Geology

2. Reading/ Background
The main function of the
respiratory system is breathing.
The main organs that perform
this function are the lungs and
the trachea (the windpipe).
Organs are a group of tissues
working together to perform a
specific job.

3. Reading/ Background
Our body is a very complex organism. For our
body to work properly, it needs energy. When we
eat, we get energy. However, to turn food into
energy, we need oxygen. Our cells need oxygen to
change food into the energy we need to function.

4. Reading/ Background
Our nose is the primary location
where oxygen enters our body.
Our nose (nasal cavity) is also
responsible for filtering the air of
dust and other stuff before the air
enters our lungs. We breathe in
using a muscle called the
diaphragm.

5. Reading/ Background
When the air enters our lungs,
bronchi tubes force the air to our
cells. Bronchi tubes are like roots of
a tree. The farther away from the
center of the lungs, the smaller the
tubes get and divide into
bronchioles.Air gets forced down
our windpipe and into our lungs.

6. Reading/ Background
At the end of the bronchi tubes
are even smaller sacs called
alveoli. Alveoli pass the oxygen to
the red blood cells that change
oxygen into energy. The red blood
cells carry the energy to other
parts of our body where energy is
needed.

7. Reading/ Background
Our Alveoli are also responsible for carrying the
waste product from cells back out to the lungs and
out of our bodies when we breathe out. This waste
product is carbon dioxide.

8. Reading/ Background
The respiratory organs have an important role in
keeping us alive. The next time you take a breath,
think about all the different organs working
together to make that happen.

9. True or False
1. The primary job of the respiratory system is
breathing.
2. There are two main organs of the respiratory
system: the lungs and the trachea.
3. Our mouth is the primary location where
oxygen enters our body.

10. Complete the Sentence
4. Organs are a group of _____________ working together for a specific job.
5. The nose is also responsible for filtering out _________ and other particles before
they enter our body.
6. The ends of our _________ tubes are small sacs called Alveoli.
7. Alveoli carry out a waste product called __________________.
8. Red blood cells carry ______________ to parts of the body where it is needed.

11. Questions
1. When do you breathe faster?
2. Why do you think you breathe faster during more
vigorous activities?
3. Other than the difficulty of the activity, what factors
do you think influence breaths/minute? Why?
4. How do you think breathing rate is related to heart
rate? Why is there a correlation?

12. Open Response
What is the difference oxygen and carbon dioxide? How
does the respiratory system move oxygen and carbon
dioxide in and out of our body?