The Respiratory
System
By: Matthew Green
The nostrils
At the top of the respiratory system, the nostrils (also
called nares) act as the air intake, bringing air into the
nose, where it's warmed and humidified.
Tiny hairs called cilia protect the nasal passageways
and other parts of the respiratory tract, filtering out
dust and other particles that enter the nose through
the breathed air.
The pharynx (throat)
The pharynx is part of the digestive system as well as
the respiratory system because it carries both food
and air.
At the bottom of the pharynx, this pathway divides in
two, one for food (the esophagus, which leads to the
stomach) and the other for air.
The epiglottis, a small flap of tissue, covers the aironly passage when we swallow, keeping food and
liquid from going into the lungs.
The larynx
The larynx, or voice box, is the uppermost part of the
air-only pipe. This short tube contains a pair of vocal
cords, which vibrate to make sounds
The trachea
The trachea, or windpipe, extends downward from
the base of the larynx.
It lies partly in the neck and partly in the chest cavity.
The walls of the trachea are strengthened by stiff
rings of cartilage to keep it open.
The trachea is also lined with cilia, which sweep fluids
and foreign particles out of the airway so that they
stay out of the lungs.
Bronchi
At its bottom end, the trachea divides into left and right air
tubes called bronchi, which connect to the lungs.
Within the lungs, the bronchi branch into smaller bronchi
and even smaller tubes called bronchioles.
Bronchioles end in tiny air sacs called alveoli, where the
exchange of oxygen and carbon dioxide actually takes place.
Each lung houses about 300-400 million alveoli
The lungs also contain elastic tissues that allow them to
inflate and deflate without losing shape and are encased by
a thin lining called the pleura.
This network of alveoli, bronchioles, and bronchi is known as
the bronchial tree.
Alveoli
Every few seconds, with each inhalation, air fills a
large portion of the millions of alveoli.
In a process called diffusion, oxygen moves from the
alveoli to the blood through the capillaries (tiny blood
vessels) lining the alveolar walls.
Once in the bloodstream, oxygen gets picked up by
the hemoglobin in red blood cells.
This oxygen-rich blood then flows back to the heart,
which pumps it through the arteries to oxygenhungry tissues throughout the body
The Thorax
The chest cavity, or thorax, is the airtight box that
houses the bronchial tree, lungs, heart, and other
structures.
The top and sides of the thorax are formed by the ribs
and attached muscles.
 The bottom is formed by a large muscle called the
diaphragm.
The chest walls form a protective cage around the
lungs and other contents of the chest cavity.
The Heart
In the tiny capillaries of the body tissues, oxygen is freed
from the hemoglobin and moves into the cells.
Carbon dioxide, which is produced during the process of
diffusion, moves out of these cells into the capillaries,
where most of it is dissolved in the plasma of the blood.
Blood rich in carbon dioxide then returns to the heart via
the veins.
From the heart, this blood is pumped to the lungs, where
carbon dioxide passes into the alveoli to be exhaled.
Diaphragm
The diaphragm (pronounced: dye-uh-fram), which
separates the chest from the abdomen, plays a lead role in
breathing.
When we breathe out, the diaphragm moves upward,
forcing the chest cavity to get smaller and pushing the
gases in the lungs up and out of the nose and mouth.
Gases involved
The air we breathe is made up of several gases.
Oxygen is the most important for keeping us alive
because body cells need it for energy and growth.
Without oxygen, the body's cells would die.
Carbon dioxide is the waste gas produced when
carbon is combined with oxygen as part of the
energy-making processes of the body. The lungs and
respiratory system allow oxygen in the air to be taken
into the body, while also enabling the body to get rid
of carbon dioxide in the air breathed out.
Asthma
 More than 20 million people in the United States have asthma,
and it's the #1 reason that kids chronically miss school.
 Asthma is a chronic inflammatory lung disease that causes
airways to tighten and narrow.
 Often triggered by irritants in the air such as cigarette smoke,
asthma flares involve contraction of the muscles and swelling of
the lining of the tiny airways.
 The resulting narrowing of the airways prevents air from flowing
properly, causing wheezing and difficulty breathing, sometimes
to the point of being life-threatening.
 Management of asthma starts with an asthma management
plan, which usually involves avoiding asthma triggers and
sometimes taking medications.
Fun facts
Each day, you breathe about 20,000 times, and by the
time you're 70 years old, you'll have taken at least
600 million breaths.
We breathe 13 pints of air every minute.
More than half a liter of water per day is lost through
breathing.
Yawning brings more oxygen to the lungs.
There is a sneeze record of 165 kilometers per hour.
Your right lung is slightly bigger then your left lung.
More Fun Facts
 At rest, the body takes in and breathes out about 10 liters of air
every minute.
 The capillaries in the lungs would extend 1,600 kilometers if
placed end to end.
 A person at rest usually breathes between 12 to 15 times a
minute.
 The breathing rate is faster in children and women than in men,
because the volume of the female & child lungs are smaller so
more oxygen is needed and more CO2 needs to be exhaled out
of the body.
 People under the age of 30 take in double the amount of oxygen
in comparison to an 80 year old.
citation
"Google Images." Google Images. N.p., n.d.
Web. 28 Aug. 2013.
"Lungs and Respiratory System."
TeensHealth. Ed. Yamini Durani, MD. Nemours, Oct.
2012. Web. 28 Aug. 2013.