Download Respiratory System You breathe about 20,000 times each day! What

Respiratory System
You breathe about 20,000 times each day! What happens when you
breathe? Air is drawn into your body with each breath. Your
respiratory system works closely with your circulatory system to
deliver oxygen to each part of your body. Carbon dioxide, which is a
waste product, is removed as well.
When you breathe in, air enters the respiratory system through the
nose. The lining of the nose produces mucus, which moistens air and
traps germs and dirt. The nose is also lined with hairs to remove dirt
and dust from the air. Then the air travels to the throat and passes
through the trachea or windpipe. A flap of tissue called the epiglottis
covers the trachea to keep food and watering from entering. Place
your fingers at the center of your neck where the neck and jaw meet
and swallow hard. You can feel the movement of the epiglottis as it
covers the windpipe when you swallow.
The trachea branches off into two smaller tubes called bronchi which
each lead to a lung through smaller and smaller branches called
bronchioles. The air then enters the tiny air sacs called alveoli,
where the blood gets rid of carbon dioxide and picks up oxygen.
It’s Greek & Latin to Me:
The prefix respir comes from Latin. It means breathe.
Your lungs are the largest organs of the
respiratory system. Which part of your lung
model represented the lungs? That’s right, the
balloons. How did you make the balloons expand?
When you pulled down on the piece of balloon at
the bottom of the cup, the balloons expanded.
That piece of balloon on the bottom of the cup
represents your diaphragm.
The diaphragm and other muscles
work to make your chest cavity
larger. Put your hands on your ribs
and take a big breath. Feel how your
chest expands? When the chest cavity
gets larger, air pressure inside the
lungs is lower than air pressure
outside the lungs and air rushes into
the lungs. When the ribs move in and
the diaphragm moves upward, the chest cavity becomes smaller and
air is forced out. All of these actions take place without our thinking
about it because breathing is an involuntary action controlled by the
nervous system.
Inside the lungs, the oxygen in the air passes across the thin
membranes of the alveoli sacs in the lungs and into the oxygen-poor
blood in the tiny capillaries that surround the sacs. The thin-walled
capillaries are so narrow they hold red blood cells in a single line. The
red blood cells contain hemoglobin, an iron-containing material that
comes easily with oxygen or carbon dioxide. Hemoglobin acts like a
transport system for oxygen and waste carbon dioxide. Oxygen-rich
blood then flows back to the left atrium of the heart and is pumped
throughout the body.