FREE NAFC Physiology Questions and Answers

Question 1

What is the primary function of the respiratory system during exercise?

Accepted Answer

To supply oxygen to the blood and remove carbon dioxide

Answer

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?

Accepted Answer

Phosphagen (ATP-PC) system

Answer

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?

Accepted Answer

To be a byproduct of anaerobic glycolysis

Answer

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?

Accepted Answer

Epinephrine (adrenaline)

Answer

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?

Accepted Answer

To produce ATP through aerobic respiration

Answer

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.

NAFC - National Association for Fitness Certification Practice Test

NAFC - National Association for Fitness Certification Practice Test

FREE NAFC Physiology Questions and Answers