8. (a) 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 with the expansion and contraction of the thoracic cavity during breathing.

The purpose of asking the person to sit down for a few minutes is to allow their breathing rate and pulse to return to a resting state. This ensures that the measurements taken later are reflective of their normal physiological state and not influenced by previous activity or exertion.

To measure the breathing rate, I counted the number of breaths taken by the individual in one minute observing the rise and fall of their chest. For the pulse, I either palpated the radial pulse on the wrist for one minute or used a heart rate monitor to count the number of beats per minute.

After the resting period, I instructed the individual to perform a specific exercise, such as hopping on the spot or jogging in place, for a set duration, typically 3 to 5 minutes. Immediately after the exercise, I measured their breathing rate and pulse again, comparing these values to those taken during the resting state.

The results indicated that after the exercise, both the breathing rate and pulse increased significantly, demonstrating the body's response to increased physical activity. After a short recovery period, both rates typically returned towards baseline levels, though they remained elevated for a brief time before normalizing.