State the location in the human body of the following muscles which are used for breathing: (i) diaphragm (ii) intercostals (b) Answer the following questions about an activity that you carried out to investigate the effect of exercise on the breathing rate or pulse of a human - Leaving Cert Biology - Question 8 - 2008

The intercostal muscles are located between the ribs. They assist in the expansion and contraction of the thoracic cavity during the breathing process.

The purpose of asking the person to sit down for a few minutes is to allow their body to reach a state of rest. This control phase ensures a baseline measurement of the breathing rate or pulse, free from the influence of prior physical activity.

To measure the breathing rate, I counted the number of breaths the person took in one minute. For measuring the pulse, I could count the number of heartbeats at the wrist or neck for the same duration.

After the resting period, I instructed the individual to perform moderate physical activity, such as running in place for a few minutes. Immediately after the exercise, I repeated my measurements of the breathing rate and pulse to observe the effects of exercise.

The investigation revealed that after exercise, the breathing rate and pulse significantly increased compared to the baseline measurements taken at rest. The findings indicated that physical activity elevates both the respiratory and heart rates.