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!