Static Lung Volumes
aka BSCC Physiology 006
Basic Science in Clinical Context Examination: 2 minutes long in 2 parts.
- Exam candidate answering a question (under exam conditions)
- Professor providing a more detailed explanation (with transcript)
Please draw a diagram to describe static lung volumes
Examinee response: Drawing and explanation in real-time video/audio
Examiner Explanation
Transcript
Static Lung Volume diagram
Lets begin with normal respiration that is the Tidal volume.
- TV: is the amount of air inhaled or exhaled in one breath during relaxed breathing and its volume is 500ml.
- IRV: inspiratory reserve volume: is the amount of air in excess of tidal volume that can be inhaled with maximum effort. (Its) volume is 3 litres.
- Remember to start labeling after the top of TV
- TV + IRV= IC- Inspiratory capacity: maximum amount of air that can be inspired after a normal tidal expiration. (Its) volume is 3.5 litres
Label the top of the inspiratory loop= maximum possible inspiration
- ERV: the amount of air in excess of tidal expiration that can be exhaled with maximum effort. Volume 1.2 litres. Remember to start labelling after the bottom of TV
- RV: amount of air remaining in the lungs after maximal expiration. Volume is 1.2 litres.
- RV is important as it keeps the alveoli inflated between breaths and mixes with fresh air on next inspiration
- RV + ERV=FRC: amount of air remaining in the lungs after a normal tidal expiration. Volume is 2.4 litres
Label at the bottom of the expiratory loop= maximum voluntary expiration
- Vital capacity VC: amount of air that can be exhaled with maximum effort after maximum inspiration.
- In other words it is IRV + TV +ERV. (Its) vol is 4.7 litres.
- VC is used to assess thoracic muscle strength as well a pulmonary function
Total lung capacity= 5900ml- maximum amount of air the lungs can contain. RV + VC
Note: These values can differ slightly depending on the source you review
Basic Science
in Clinical Context
