Free NAFC Physiology Questions and Answers — Questions and Answers
Question 1: What is the primary function of the respiratory system during exercise?
- To maintain blood pH balance
- To supply oxygen to the blood and remove carbon dioxide (Correct answer)
- To transport nutrients to muscles
- To regulate body temperature
Correct answer: To supply oxygen to the blood and remove carbon dioxide
During exercise, muscles demand more oxygen to produce energy and generate more carbon dioxide as a waste product. The respiratory system's primary role is to facilitate this gas exchange, bringing in oxygen from the atmosphere and expelling carbon dioxide from the body. This process is vital for sustaining muscle activity and maintaining physiological balance.
Question 2: Which energy system is primarily used during a 100-meter sprint?
- Oxidative phosphorylation
- Phosphagen (ATP-PC) system (Correct answer)
- Aerobic system
- Anaerobic glycolysis
Correct answer: Phosphagen (ATP-PC) system
The phosphagen system, also known as the ATP-PC system, provides immediate energy for very short, high-intensity activities like a 100-meter sprint. It rapidly regenerates ATP using stored phosphocreatine in the muscle cells. This system can only sustain maximal effort for about 5-10 seconds before depleting its stores.
Question 3: What is the role of lactic acid in muscle metabolism during high-intensity exercise?
- To stimulate muscle growth
- To be a byproduct of anaerobic glycolysis (Correct answer)
- To provide long-term energy
- To act as a buffer for pH balance
Correct answer: To be a byproduct of anaerobic glycolysis
During high-intensity exercise when oxygen supply is insufficient for aerobic metabolism, muscles rely on anaerobic glycolysis for energy. Lactic acid (or lactate) is produced as a byproduct of this process, specifically when pyruvate is converted to lactate. While often associated with muscle fatigue, lactate can also be used as a fuel source by other tissues or converted back to glucose.
Question 4: Which hormone is responsible for increasing heart rate and blood pressure during exercise?
- Cortisol
- Epinephrine (adrenaline) (Correct answer)
- Insulin
- Glucagon
Correct answer: Epinephrine (adrenaline)
Epinephrine, also known as adrenaline, is a hormone released by the adrenal glands in response to stress or exercise. It plays a key role in the "fight or flight" response, increasing heart rate, blood pressure, and dilating airways to prepare the body for intense physical activity. This physiological response enhances oxygen delivery and energy mobilization to working muscles.
Question 5: What is the main function of the mitochondria in muscle cells?
- To produce ATP through aerobic respiration (Correct answer)
- To store calcium
- To synthesize proteins
- To store glycogen
Correct answer: To produce ATP through aerobic respiration
Mitochondria are often called the "powerhouses" of the cell because they are the primary sites for aerobic respiration. In muscle cells, they efficiently convert glucose and fatty acids into adenosine triphosphate (ATP), the main energy currency of the cell, especially during sustained activity. This process requires oxygen and generates a large amount of ATP.
Question 6: How does regular aerobic exercise affect resting heart rate?
- It decreases resting heart rate (Correct answer)
- It increases resting heart rate
- It has no effect on resting heart rate
- It fluctuates resting heart rate
Correct answer: It decreases resting heart rate
Regular aerobic exercise strengthens the heart muscle, making it more efficient at pumping blood. A stronger heart can pump more blood with each beat (increased stroke volume), meaning it doesn't need to beat as frequently to meet the body's demands. Consequently, a well-trained individual typically has a lower resting heart rate compared to someone who is sedentary.
Question 7: Which physiological process is primarily responsible for muscle growth following resistance training?
- Glycogen storage
- Protein synthesis (Correct answer)
- Protein catabolism
- Lipid oxidation
Correct answer: Protein synthesis
Resistance training causes microscopic damage to muscle fibers, which then triggers a repair and adaptation process. Protein synthesis is the physiological process where new muscle proteins are created, leading to an increase in muscle fiber size and strength. This net increase in protein content is the fundamental mechanism behind muscle hypertrophy or growth.
Free NAFC Physiology Questions and Answers
What is the primary function of the respiratory system during exercise?