5. The NASAL CAVITY (nose) is the preferred
entrance for outside air into the Respiratory
System. The hairs that line the inside wall are
part of the air-cleansing system.
Air also enters through the ORAL CAVITY
(mouth), especially in people who have a mouth-
breathing habit or whose nasal passages may be
temporarily obstructed, as by a cold.
The PHARYNX (throat) collects incoming air from
the nose and passes it downward to the trachea
(windpipe).
6. The larynx forms the entrance to the lower
respiratory system. With the help of the
epiglottis (a leaf-shaped flap), the larynx
prevents food or liquid from entering the lower
respiratory tract while swallowing.
The TRACHEA (windpipe) is the passage
leading from the pharynx to the lungs.
The trachea divides into the two main
BRONCHI (tubes), one for each lung. These, in
turn, subdivide further into bronchioles.
7.
8. One bronchus leads to the right lung,
the other to the left lung. The bronchi also
contain C-shaped cartilage rings like
the trachea.
Deeper in the lungs, each bronchus divides
into secondary and tertiary bronchi, which
continue to branch to smaller airways called
the bronchioles.
9. The bronchioles end in air sacs called
the alveoli. Alveoli are bunched together into clusters to
form alveolar sacs. On the surface of each alveolus, there
is a network of capillaries carrying blood that has come
through veins from other parts of the body. Here gas
exchange occurs -- carbon dioxide from the blood is
exchanged for oxygen from the alveoli. After the blood
is oxygenated, it goes to the heart
(between the two lungs), where it is pumped out to all of
the body tissues and extremities. When you breathe out,
the carbon dioxide is exhaled and expelled from the body.
10. The lungs are the main organs of the respiratory system. In
the lungs oxygen is taken into the body and carbon dioxide is
breathed out. The red blood cells are responsible for picking
up the oxygen in the lungs and carrying the oxygen to all the
body cells that need it. The red blood cells drop off the
oxygen to the body cells, then pick up the carbon dioxide
which is a waste gas product produced by our cells. The red
blood cells transport the carbon dioxide back to the lungs and
we breathe it out when we exhale.
The RIGHT LUNG is divided into three LOBES, or sections.
The left lung is divided into two LOBES.
11. The DIAPHRAGM is the strong wall of
muscle that separates the chest cavity
from the abdominal cavity. By moving
downward, it creates suction to draw in
air and expand the lungs.
Upon exhalation, the diaphragm relaxes
and returns to its domelike shape, and air
is forced out of the lungs.
12.
13. Which is larger, left lung
or right lung?
• the right lung is larger and has more
lobes than the left lung (3 vs 2). This
is because the heart is normally
located on the left side, and takes up
space in what would have been the
left lung.
14. Why Do I Yawn?
When you are sleepy or drowsy the
lungs do not take enough oxygen
from the air. This causes a
shortage of oxygen in our bodies.
The brain senses this shortage of
oxygen and sends a message that
causes you to take a deep long
breath---a YAWN.
15. Why Do I Sneeze?
Sneezing is like a cough in the upper
breathing passages. It is the body's way
of removing an irritant from the sensitive
mucous membranes of the nose. Many
things can irritate the mucous membranes.
Dust, pollen, pepper or even a cold blast of
air are just some of the many things that
may cause you to sneeze.
16. What Causes Hiccups?
Hiccups are the sudden movements
of the diaphragm. It is involuntary
--- you have no control over hiccups,
as you well know. There are many
causes of hiccups. The diaphragm
may get irritated, you may have
eaten to fast, or maybe some
substance in the blood could even
have brought on the hiccups.
