Pulmonary Lab

Based on the negative feedback hypothesis, predict how your breathing will change by the end of each breathing perturbation. Explain your reasoning.

(Hint: Think about what will happen to the CO2 and O2 levels in the air in the bag and your lungs as you breathe into the bag for several minutes.)

Perturbation 1:

Hyperventilating

Hypothesis:

Justification:

Perturbation 2:

Control: Breath normally

Hypothesis:

Justification:

Perturbation 3:

Re-breathing

Hypothesis:

Justification:

Materials:

• Paper bag

• Stop watch/timer

Instructions:

Each perturbation will be used 3 times, and the times will be averaged

Prior to each perturbation breathing normally for 60 seconds

Following the perturbations please return to normal breathing for at least 1 minute.

Perturbation 1:

Hyperventilation- Following the 60 seconds of normal breathing please hyperventilate for 45 seconds. Immediately following the 45 seconds take a deep breath and hold your breath for as long as possible.

Trial 1: _____________ Average:____________

Trial 2:_____________

Trial 3: _____________

Perturbation 2:

Control: Breath normally for 30 seconds followed by holding your breath for as long as possible. Use the timer to record how long you can hold your breath

Trial 1: _____________ Average:____________

Trial 2:_____________

Trial 3: _____________

Perturbation 3:

Re-breathing: Following the 60 seconds of normal breathing please begin to breath in and out of the paper bag (like you would see on old airplane movies), for 45 seconds. At the end of the 45 seconds take a deep breath and record how long you can hold your breath.

Trial 1: _____________ Average:____________

Trial 2:_____________

Trial 3: _____________

Results:

1. Of the 3 experimental arms, which do you hypothesize will cause you to hold your breath longer and what is the physiological basis for your hypothesis, was it correct?

2. Which one did result in the longest breath holding, and from the lecture outlines, what is the physiological reasoning?

3. Where you right or wrong? If you were wrong what mechanism did you forget about or misunderstand?

Questions

1. When you are physically active, contracting muscle cells use lots of ATP, so the rate of cellular respiration increases. How does your breathing change during physical activity? Why are these changes useful?

2.  The respiratory system includes the lungs and breathing muscles and the circulatory system includes the heart, blood and blood vessels. Explain why a person needs to have both a respiratory system and a circulatory system to provide the body's cells with the O2 needed for cellular respiration.

3. On the top of a high mountain, air pressure is significantly lower than at sea level, so there is less O2 in a given volume of air. Suppose a person at high altitude maintained the same rate and depth of breathing as he had at sea level. What would happen to the O2 levels in his blood? Explain your reasoning.

4.  What changes in breathing could maintain relatively constant O2 levels in the blood for a person who has gone from sea level to high altitude?

5. Create a flowchart diagram to show how negative feedback regulation could change the rate and/or depth of breathing to maintain relatively constant levels of CO2 in the blood.