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
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
in Clinical Context
Associate Professor Curtin Medical School, Curtin University. Emergency physician MA (Oxon) MBChB (Edin) FACEM FFSEM Sir Charles Gairdner Hospital. Passion for rugby; medical history; medical education; and asynchronous learning #FOAMed evangelist. Co-founder and CTO of Life in the Fast lane | Eponyms | Books | Twitter |