Respiratory System
Without oxygen the
cells within a
body would die. The organs of the respiratory system bring the needed oxygen
into the body for the cells to use. They also rid the body of waste products,
such as carbon dioxide, that the cells produce.
The main organs of the respiratory system are the lungs. The other parts include the trachea, mouth, nose, epiglottis, and larynx.
The trachea is a long, hollow tube that extends from the mouth to the lungs. It has rings made of cartilage that surround it. These hard rings help keep the trachea from collapsing on itself and stopping the flow of oxygen.
The epiglottis is a flap of tissue that
opens and closes.
It is located at the back of the throat
and seals the trachea during eating and drinking to prevent fluids or solids
from entering the trachea and reaching the lungs.
The larynx (or voicebox) is also located near the back of the throat. It is attached to the trachea and contains the vocal cords, which allow speech to occur when air is released past them from the lungs.
The larynx also helps keep food from entering the trachea. There is a thick shield of cartilage that surrounds the larynx to protect it.
The lungs are a
pair of organs located in the chest. Each spongy lung is about 10-12 inches long
and is basically coned shaped.
They weigh only about 2 pounds and possess a special lining on the walls that
keep the lungs from collapsing on themselves.
The right and left side of the lungs are separated by the heart, trachea, esophagus, and blood vessels.
The right side of the lungs consists of 3
sections or lobes. The left side is smaller because its space within the chest
is shared with the heart. The left side only has 2 lobes.
Air is usually
inhaled through the nose. Inside the nose are tiny hairs that help trap
dirt and other particles. Once cleaned, the air is then warmed in the nasal
cavity. This warmed air then
continues its journey by passing through a long tube called the trachea.
When the trachea reaches the lungs it
divides into two tubes called bronchi. One bronchi goes to each side of the
lungs.
Once inside, the
bronchi divides into smaller branches called bronchioles, which keep getting
smaller and smaller.
They finally end in microscopic sacs called alveoli. It is inside the alveoli that the exchange of carbon dioxide for oxygen takes place.
There are about 300 MILLION of these
airsacs in the lungs, and they empty and fill about 15,000 times a day.
Inside
the lungs there are also microscopic hairs called cilia. These hairs help trap
inhaled particles such as dust and other pollutants.
These
hairs move the particles upward like an escalator into the throat to be coughed
or sneezed out of the body.
The
inflation of the lungs, which allows inhalation is controlled by a thick muscle
located at the bottom of the chest cavity. This muscle is called the diaphragm.
The
diaphragm is attached to the sternum, vertebrae, and rib cage. There are holes
in it to allow such things as the aorta, veins, and the esophagus, which carries
food to the stomach to pass through to the abdomen.
When
a person takes a breath, the diaphragm contracts and is pulled downward. This
creates more space in the chest. The lungs fill with air to help fill this
space. When a person exhales, the diaphragm relaxes and rushes upward. There is
no longer any empty space in the chest and the lungs are forced to rid
themselves of the air they were storing.
This
process of inflating and deflating the lungs is carried on about 10-16 times a
minute. That means at rest, a person takes about one breath every 6 seconds.
A
healthy adult can draw in about 3 1/2 to 5 liters of air in a single breath. At
rest, though, only about 5% of this air is used by the body. The rest is
promptly exhaled.
When
a person needs extra oxygen, the rib cage can easily expand creating an even
larger area for the lungs to fill.
When
the diaphragm contracts and pulls downward, it not only allows the lungs to
fill, but it also helps food digest. As it pulls down it hits the stomach. This
motion helps move food particles inside the stomach around making them break
into smaller and smaller pieces.
Diseases of the lungs include pneumonia, which is caused by viruses and bacteria, cancers, bronchitis, emphysema, asthma, and fibrosis, which is a scarring of the lung tissue caused by exposure to certain chemicals or substances such as asbestos and coal dust.
Due
to disease or injury, a person can survive with only one side of the lungs.
Lungs are also an organ that can be transplanted.
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