The document summarizes the main parts and functions of the respiratory system. It describes how air enters through the nose and is filtered before passing through the pharynx, larynx, trachea, bronchi and bronchioles to the lungs. The lungs contain millions of alveoli where gas exchange occurs to oxygenate blood and remove carbon dioxide. A key organ is the diaphragm, which controls breathing by contracting and flattening to increase lung space during inhalation.

1. Respiratory
System

2. Respiratory System
Respiratory system is a
series of organs responsible
for taking in oxygen and
expelling carbon dioxide.
The main organs of the
respiratory system are the
lungs which carry out the
exchange of gases as we
breathe.

3. Parts of the Respiratory System
Nasal Cavity
Pharynx and Larynx
Trachea, Bronchi,
Bronchioles and
Alveoli
Lungs
Diaphragm

4. Nasal Cavity
The nostrils are the opening
into the nasal passages that
are lined with hairs.
Nostrils have cilia. The cilia
filter the dust and other
particles present in the air.
They also protect the nasal
passages and other regions
of the respiratory tract.

5. Pharynx and Larynx
The pharynx is also
called throat. It is the
common passageway
for both food, water,
and air. Below the
epiglottis is the larynx
or voice box.

6. Pharynx and Larynx
The larynx contains two vocal
cords that vibrate when air
passes by them. The larynx is
the main site for sound
production. To prevent food
from entering the windpipe or
the trachea, the epiglottis
closes the larynx when
swallowing. This prevents food
and water to enter the passage.

7. Trachea, Bronchi, Bronchioles, Alveoli
The trachea is known as
windpipe. It is made up
of muscles and elastic
fibers with rings of
cartilage lined with
cilia. It filters the air we
inhale and branches into
the bronchi.

8. Trachea, Bronchi, Bronchioles, Alveoli
The bronchi are two
tubes that carry air
into the lungs.
Bronchial tubes also
branch into smaller
tubes called
bronchioles.

9. Trachea, Bronchi, Bronchioles, Alveoli
Alveoli are grape-like structures
at the end of bronchioles. The
bronchioles and the alveoli
together make up the lungs. The
alveoli increase the surface of
the lungs for greater exchange
of gases to collect more oxygen.
It also protects the lungs from
bacteria and other harmful
microorganisms.

10. Lungs
 The lungs are in the chest cavity
surrounded by the rib cage. The lungs
are the main organ of the respiratory
system. This is where exchange of
gases occurs. This is the site where
oxygen is taken in and carbon dioxide
is expelled out. Each lung is covered
with pleural membrane. This
membrane produces slippery fluid
that allows the lungs to glide freely
during breathing.

11. Diaphragm
 The diaphragm is a dome-shaped
muscle that controls breathing, which
is located at the bottom of the lungs.
During respiration, the diaphragm
flattens out and pulls forward, making
more space for the lungs. When we
inhale or breathe in, the diaphragm
contracts and pulls downward. This
movement increases the space in the
lungs, which pulls air into it. When we
exhale or breathe out, the diaphragm
expands.

12. Pathway of the
Air

13. Pathway of the Air
Nose/Nostrils
Pharynx
Larynx Trachea Bronchi Lungs
Air enters to the
Air gets moistened,
filtered, and
warmed
Lungs contains millions of alveoli.
Oxygen and carbon dioxide occur in
alveoli of the lungs.
Contains alveoli
in which exchange
of gases occurs.
Pharynx
Larynx Bronchi
Bronchi

14. ACTIVITY 1
 Direction: Identify what is being describe in the following
statements. Write your answer on a ¼ sheet of paper.
1. They are the openings into the nasal passages that are
lined with hairs
2. It filters the dust and other particles present in the air.
3. It is called the throat.
4. It contains two vocal cords that vibrate when air passes
by them
5. It is known as the windpipe.

15. ACTIVITY 1
6. These are two tubes that carry air into the lungs
7. These are smaller tubes of bronchi
8. They are grape-like structures at the end of
bronchioles
9. They are located in the chest cavity surrounded
by the rib cage.
10. A domed- shaped muscle that controls breathing
which is located at the bottom of the lungs.

16. ACTIVITY 2
Complete the paragraph by writing the word on
the blank that completes the sentence.
When air enters our nose, it passes through the
(1)_________________.It passes to the pharynx and then to
the (2)_________________ Then the air continues to pass
through the (3)___________________down to the lungs.
The (4) __________ contain millions of alveoli. It is also the
sites of the (5) ______ exchange between air and blood.