7.3. MEASURING THE PROCESS

Question 1

how can you measure the capacity of lungs?

Answer 1

• peak flow meter
• vitalographs
• spirometer

Question 2

what is a peak flow meter?

Answer 2

• simple device that measures the rate at which air can be expelled from the lungs
• people who have asthma often use these to monitor how well their lungs are working

Question 3

what are vitalographs?

Answer 3

• more sophisticated versions of the peak flow meter
• patient being tested breathes out as quickly as they can through a mouthpiece, and the instrument produces a graph of the amount of air they breathe out and how quickly it is breathed out
• this volume of air is called the forced expiratory volume in 1 second

Question 4

what is a spirometer?

Answer 4

• commonly used to measure different aspects of the lung volume, or to investigate breathing patterns
• many different forms

Question 5

what are the components of lung volume?

Answer 5

• tidal volume
• vital capacity
• inspiratory reserve volume
• expiratory reserve volume
• residual volume
• total lung capacity

Question 6

what is tidal volume?

Answer 6

• volume of air that moves in and out of the lungs with each resting breath
• around 500cm3 in most adults at rest, which uses about 15% of the vital capacity of lungs

Question 7

what is vital capacity?

Answer 7

• volume of air that can be breathed in when the strongest possible exhalation is followed by the deepest possible intake of breath

Question 8

what is inspiratory reserve volume?

Answer 8

• maximum volume of air you can breathe in over and above a normal inhalation

Question 9

what is expiratory reserve volume?

Answer 9

• extra amount of air you can force out of your lungs over and above the normal tidal volume of air you breathe out

Question 10

what is residual volume?

Answer 10

• volume of air left inside your lungs when you have exhaled as hard as possible
• cannot be measured directly

Question 11

what is total lung capacity?

Answer 11

• sum of vital capacity and the residual volume

Question 12

what is the breathing rate?

Answer 12

• number of breaths taken per minute

Question 13

what is the ventilation rate?

Answer 13

• total volume of air inhaled in one minute

Question 14

how do you measure ventilation rate?

Answer 14

tidal volume x breathing rate (per minute)

Question 15

what happens when oxygen demands of the body increase, for example during exercise?

Answer 15

• tidal volume of air moved in and out of the lungs with each breath can increase from 15% to as much as 50% of the vital capacity
• breathing rate can also increase
• ventilation of lungs and therefore the oxygen uptake during gaseous exchange can be increased to meet the demands of the tissues