Why do you need to breathe?
All of the cells in the body require oxygen. Without it, they
couldn't move, build, reproduce, and turn food into energy. Your
body gets oxygen from breathing in air which circulates to all parts of
This chart of the respiratory system shows the
breathing. Breathing is the process by which oxygen from the air
is brought into the lungs and circulated throughout the body in the
blood. At the same time, the blood gives up waste
matter, also called carbon dioxide, which is transported out of the
lungs as we breathe out.
Nasal cavity (nose): the preferred entrance for outside
the respiratory system
Oral cavity (mouth): air also enters the body here
Adenoids: lymph tissue at the top of the throat that helps resist
Tonsils: lymph nodes in the wall of the pharynx that are often
removed when infected
Pharynx (throat): catches incoming air from the nose and passes
it downward to the windpipe
Epiglottis: a flap of tissue that guards the entrance to the
Larynx (voice box): contains the vocal cords
Esophagus: the passage leading form the mouth and throat to the
Trachea (windpipe): the passage leading from the pharynx to the
Ribs: bones supporting and protecting the chest cavity
Bronchi (tubes): trachea divides into these two main tubes, one
for each lung
Cilia: the bronchial tubes are lined with these very small hairs
that have a wave-like motion
Mucus: the movement of the cilia carries mucus upward into the
throat where it is coughed up or swallowed
Diaphragm: wall of musle that separates the chest cavity from the
Alveoli: small sacs where air goes when breathed in
Capillaries: blood vessels
Pulmonary Artery / Vein: blood is carried to the
the pulmonary artery and taken away by the pulmonary vein
Pretend you are a volunteer going off to war. In
be admitted into the army, you must first pass a physical fitness
examination. Although you must complete various portions of the
test before you leave, we are focusing on respiration rates
today. Begin by using a stop watch and counting your resting
respiration rate. This can be done by counting how many times you
breathe in a minute. Record your data in the chart below.
Next, run in place for one minute. As soon as you are done, count
how many times you breathe in a minute. Record this number on the
table. Finally, run in place for three minutes at a fatser
pace. When you finish, count how many times you breathe in a
minute. Record this number below. Work with your assigned
partner to complete the activity.
Respiratory Rate Table:
after 1 minute
after 3 minutes
1. What did you find about your breathing rate as you began to
run? Did your respiration rate increase or decrease? Why
do you think this occurred?
2. What was your physical reaction to the running? How did
your heart and lungs respond?
3. Do you have any insights as to why respiration was affected
when you ran compared to when you were at rest?
When we exercise, our muscles are using up a lot of energy and our
cells need to get more energy out of the food we've eaten. This
takes lots of oxygen, so our lungs breathe in and out faster to get
more oxygen out of the air. They in turn produce more carbon
dioxide, so the waste must be exhaled. When we are resting, our
cells are not working as hard, so less energy is used and our breathing
can slow down.
You have probably noticed that when you are exercising, your heart
beats more quickly. This occurs so that the blood can carry
oxygen to the cells faster. Your heart and lungs work together to
make sure every cell in your body receives the right amount of oxygen.
When you rest, your cells aren't working hard, so they require less
oxygen to function. In addition, they produce less carbon
dioxide. As a result, you do not have to breathe as often as when
you are moving. Because your heart and lungs work as a team, when
your lungs are not working hard, neither is your heart!
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.
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.
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.