Exercise 10: Acid/base Balance Worksheet

Exercise 10: Acid/Base Balance Worksheet

Respiratory Acidosis and Alkalosis

Activity 1: Normal Breathing

1. At 20 seconds, pH = 7.4

2. At 40 seconds, pH = 7.4

3. At 60 seconds, pH = 7.4

4. Did the pH level of the blood change at all during normal breathing? If so, how? The pH did not change during the normal breathing.

5. Was the pH level always within the "normal" range for the human body? Yes it was.

6. Did the PCO2 level change during the course of normal breathing? If so, how? No it did not change either.

Activity 2a: Hyperventilation - Run 1

1. At 20 seconds, pH = 7.48

2. At 40 seconds, pH = 7.52

3. At 60 seconds, pH = 7.65

4. Maximum pH = 7.65

5. Did the pH level of the blood change at all during this run? If so, how? Yes it did, when the breathing rate changed the pH began to rise.

6. Was the pH level always within the "normal" range for the human body? If not, when was the pH value outside of the normal range, and what acid/base imbalance did this pH value indicate? The pH was within the normal range until the subject started to hyperventilate. The rising pH indicated that the body was expelling CO2 and H+.

7. Did the PCO2 level change during the curse of this run? If so, how? Yes, the PCO2 level dropped from 40 to 19.7 because the body was getting rid of CO2 by hyperventilating.

8. If you observed an acid/base imbalance during this run, how would you expect to renal system to compensate for this condition? The renal system would generate H+ and excrete HCO3- to counteract the respiratory system and lower the pH back to homeostasis.

9. How did the hyperventilation trace differ from the trace for the normal breathing? Did the tidal volumes change? The tidal volume and the rate increased drastically from normal breathing.

10. What might cause a person to hyperventilate? Anxiety, fear, and even high altitudes with a decrease in oxygen would cause to body to breath faster and deeper to maintain homeostasis.

Activity 2b: Hyperventilation - Run 2

1. What happened to the trace after the 20-second mark when you stopped the hyperventilation? Did the breathing return to normal immediately? Explain your observation. In order to allow the CO2 levels to return to normal the body went into a state of apnea after the hyperventilating stopped. For every 2 seconds the body was in a state of hyperventilation it maintained a state of apnea for the same duration.

Activity 3: Rebreathing

1. At 20 seconds, pH = 7.35

2. At 40 seconds, pH = 7.3

3. At 60 seconds, pH = 7.23

4. Did the pH level of the blood change at all during this run? If so, how? The pH level decreased during the state of rebreathing.

5. Was the pH level always within the "normal" range for the human body? If not, when was the pH value outside of the normal range, and what acid/base imbalance did this pH value indicate? The pH went outside the normal range around 20 seconds. This indicated that the body had an excess amount of CO2 and H+ building up in the blood which caused the pH to lower.

6. Did the PCO2 level change during the course of this run? If so, how? Yes, it increased because it was building up in the body.

7. If you observed an acid/base imbalance during this run, how would you expect the renal system to compensate for this condition? The renal system would compensate by excreting H+ into the urine and adding HCO3- (bicarbonate) to the blood stream to increase the pH.

8. How did the rebreathing trace differ from the trace for normal breathing? Did the tidal volumes change? The tidal volume increased to try to compensate for the decreased oxygen saturation in the rebreathed air.

9. Give examples of respiratory problems that would result in pH and PCO2 patterns similar to what you observed during rebreathing? Essentially anything that has a negative impact on the respiratory system itself like airway obstruction/blockage, inner-cranial pressure (ICP), narcotics overdose, or respiratory problems like asthma, bronchitis, emphysema, or pneumonia.

Renal System Compensation

Activity 4: Renal Response to Normal Acid/Base Balance

1. At normal PCO2 and pH levels, what level of H+ was present in the urine? Normal

2. What level of [HCO3-] was present in the urine? Normal

3. Why does the blood pH value change as PCO2 changes? Because the PCO2 is directly proportional to the H+ levels which are inversely proportional to the pH level of the blood.

4. How does the blood pH value change as Pco2 changes? The Pco2 binds with the water in the blood to form carbonic acid

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