Lesson 3 - Lung capacity Flashcards
Three instruments used to measure the volume capacity of the lungs?
- A peak flow meter
- Vitalographs
- A spirometer
A peak flow meter:
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.
Vitalographs:
More sophisticated version of a peak flow meter. The patient being tested breathes out as fast as they can through a mouthpiece, and the instrument produces a graph of the amount of air they breath out and how quickly it is breathed out. This volume of air is called the forced expiratory volume in 1 second.
Spirometer:
Commonly used to measure different aspects of lung volume.
What aspects of lung volume can be measured?
- Tidal volume
- Vital capacity
- Inspiratory reserve volume
- Expiratory reserve volume
- Residual Volume
- Total lung capacity
Tidal volume:
The volume of air that moves into and out of the lungs in each resting breath.
What is the tidal volume of an adult?
500cm^3
This uses 15% of the vital capacity of the lungs
Vital capacity:
The volume of air that can be breathed in when the strongest possible exhalation is followed by the deepest possible intake of breath.
Inspiratory reserve volume:
Maximum volume of air you can breath in over and above a normal inhalation.
Expiratory reserve volume:
The extra volume of air you can force out of your lungs over and above the normal tidal volume of air you breath out.
Residual volume:
The volume of air that is left in your lungs after the hardest possible exhalation. This can not be measured directly.
Total lung capacity:
The sum of the vital capacity and the residual volume.
When does breathing rhythm change?
The pattern and volume of breathing changes as the demands of the body change.
Breathing rate:
The number of breaths taken per minute
Ventilation rate:
The total volume of air inhaled in one minute.
