Gas Transport, Breathing, and Hemoglobin Loading Lab

Introduction

Hemoglobin is a kind of oxygen-transport pigment evolved by animals. It can easily bind and unbind oxygen, therefore making it an effective transport unit for large multicellular organisms. By providing a way for the body to carry oxygen other than simply allowing it to dissolve into the blood, hemoglobin increases the oxygen-carrying capacity of the blood. The circulatory system carrying the blood is dependent upon the heart. The heart works as a pump, and the beating of the heart involves a contraction called systole and relaxation called diastole. Blood pressure is also produced by the heart, causing blood to flow through the system. The highest pressure at the time of the heart’s contraction is called systolic pressure, and the lowest pressure reached during relaxation is called diastolic pressure.

In this lab, we will be evaluating the effects of external stimuli on internal processes such as blood pressure, heart rate, oxygen saturation, and the galvanic skin response.

Equipment & Materials

• LabQuest
• LabQuest Blood Pressure Cuff Extension
• Pulse Oximeter
• BIOPAC Disposable Electrodes
• BIOPAC Electrode Lead Set
• BIOPAC EDA setup
• BIOPAC Student Lab System

Pre-Lab Questions

1. How does oxygen bind to hemoglobin?

2. What does systolic pressure measure? What about diastolic? What is a normal systolic and diastolic pressure in young adult humans?

3. Why is blood pressure measured in mmHG?

4. In which two locations in the body does gas exchange occur?

5. What are the pulse oximeters measuring, other than heart rate?

Activity 1: Blood Pressure and Stressful Stimuli

For our first activity, we’ll be evaluating how outside (stressful) stimuli affect blood pressure. Connect the sensor to the first channel of the LabQuest2. Make sure to work with a partner so you can easily and accurately measure your blood pressure.

1. Connect the Blood Pressure Sensor to the interface. Attach the rubber hose from the cuff to the connector on the sensor.
2. Wrap the cuff firmly around your partner’s arm, approximately 2 cm above the elbow. The two rubber hoses from the cuff should be positioned over the bicep muscle (brachial artery) and not under the arm. Important: The person having his or her blood pressure measured must remain still during data collection—no movement of the arm or hand during measurements.
3. Begin data collection.
4. Quickly and repeatedly squeeze the bulb to inflate the cuff on your partner’s arm. Continue inflating the cuff to a pressure between 150 and 170 mm Hg. A meter in the data-collection software will display the live pressure readings from the sensor. When the maximum pressure is reached, set the bulb pump down onto the table. The built-in pressure release valve will slowly deflate the cuff.
5. After the pressure drops to 50 mm Hg, you may press down on the pressure release valve to release any air left in the cuff. Have one partner measure the blood pressure for the other, then switch. Measure for each of the three following steps: before holding the snake, while holding the snake, and after. Record your data below.

Activity 2: Blood Pressure and Calming Stimuli

For the second activity, we will be measuring blood pressure before and after doing yoga for ten minutes. Use the same steps from the first activity to set up the LabQuest and use before and after doing yoga.

Activity 3: Oxygen Saturation

For this activity we will measure our blood’s oxygen saturation levels before and after three different activities. First, use a pulse oximeter to measure your oxygen saturation beforehand. Then, take one of the paper bags and take deep breaths in it for 1 minute. If you feel lightheaded or otherwise unwell, feel free to stop! Then find your oxygen saturation again.

Next, take your oxygen saturation before and after holding your breath for as long as you can. Don’t push yourself too hard, just do what you comfortably can. Do three different trials and record the difference in percent oxygen from before and after for each. Give yourself a minute after each test to recover before starting again.

Finally, we will be performing aerobic exercise to see its effect on our oxygen saturation. Measure your oxygen saturation first, then do 30 jumping jacks, and measure again.

Activity 4: Biopac

For this activity we will be evaluating how well we can consciously and intentionally affect processes controlled by the autonomic nervous system.

1. Turn on the laptop with the downloaded BIOPAC program.
2. Plug in the BIOPAC both into a power source and into the laptop. Then flip on the switch on the back of the BIOPAC.
3. Click on the BIOPAC icon.
4. Select Lesson 14 (L14) Biofeedback.
5. Allow the file to stay “Noname” and click okay. Click “use it”. When it asks for the adobe update, click no.
6. Then, follow the online prompts.

Spend the first 30 seconds thinking stressful, negative thoughts and trying to raise GSR and heart rate, and the other 30 seconds calming down, thinking positive and optimistic thoughts to lower GSR and heart rate. After collecting data, click suspend, then done, and then choose to analyze current data. Scroll over the graphs to find the lowest and highest values for each of the following on the table.

Post-Lab Questions

1. Did holding the snake affect blood pressure? If so, did it make blood pressure rise or fall, and why?

2. Similarly, how did doing yoga affect blood pressure? Did it make blood pressure rise or fall? Why?

3. Did the aerobic exercise lower oxygen saturation? Would you expect anaerobic exercise to have the same or a different result?

4. Was it possible to heighten or lower GSR and heart rate by consciously thinking about it? Why or why not?

5. Physiologically speaking, how does being calm lower blood pressure and vice versa?