HBS
3.3.1
How often do you think about your
breathing?
Breathing
• Why?
• What is the relationship between breathing
and exercise?
Why can the human body last for only a few
minutes without oxygen, yet can survive for
days without food or water?
• Remember the rules of three that you read in
Activity 3.1.2; it listed three minutes as the time a
body can go without air; yet it was three days
without water and three weeks without food!
• From these time limits it is easy to see that
oxygen must be very important and that the body
needs a near constant supply.
• What does oxygen do in the body that is so
important for survival?
The body needs oxygen to make ATP,
the energy molecule for all cells.
• Even the name of the process that ultimately
produces ATP from the breakdown of food
molecules emphasizes the importance of
oxygen in the process.
• Remember, the process is called oxidative
phosphorylation.
• Think back to what you have already learned
about adenosine tri-phosphate. Remember it
is formed by combining the nucleoside
adenosine with three high energy phosphate
groups. The final step to produce the ATP
molecule is the addition of the third
phosphate group, and this process requires
the enzyme ATP synthase located in the
membrane of the mitochondria.
• It is that final step that requires oxygen. If there
are no oxygen molecules available, then ATP can
not be produced and the body’s cells do not have
a source of energy. The lack of oxygen in a cell is
analogous to a battery running out in an
electronic device. As the battery loses power, the
device slows down; once the power is gone, the
device stops working. In a cell, when oxygen is
not available, the cell processes slow down as the
remaining ATP is used; once all the ATP is gone,
the cell can no longer function and dies.
• Without oxygen the cell can not replace the
ATP it uses; consequently, once all the stored
ATP is gone, the cell no longer has a source of
energy and cell functions stop.
• The body’s source of oxygen is the air in the
atmosphere. Getting oxygen from the air to
each cell in the body is a complex and
coordinated effort of the respiratory and the
cardiovascular systems.
• How often do you think about your breathing?
Every minute your body is taking in the oxygen
it needs and getting rid of waste gases. It is a
good thing that you don’t have to think about
breathing because you would have little time
to think about anything else.
• In this activity, you will investigate the
structure of the respiratory system and its
connection to the cardiovascular system.
At the conclusion of this activity, you
will be able to:
• Describe the structure and function of the
components of the respiratory system.
• Explain how oxygen is transferred from the
lungs to blood.
• Explain how oxygen is transferred from blood
to the body cells.
• Apply your knowledge of the oxygen transport
system to explain the consequences of various
disease conditions.
3.3.1
• What will you turn in?
– After you complete 1-10, you need to show my
your diagram of the lung: Indicate the three major
segments of the right lobe, and the two major segments of the left
lobe. Include and label the bronchi and bronchioles in your diagram.
– Form a group of three – each of you need to
answer two of the conclusion questions.
Tomorrow, you will spend the first ten minutes of
class discussing your answers and questions! 