In the lungs oxygen passes from the alveoli to the blood. Describe and explain the features that make this process rapid and efficient.
The graph shows the pressure changes in the lungs during the period of one breath (inspiration and expiration) in a person at rest. Use your knowledge of breathing to explain the changes in pressure during inspiration and expiration. The letters on the graph are there to help you to refer to different parts of the curve
the maximum volume of air that can be exchanged between maximum inspiration and maximum expiration
it’s the sum of IRV + TV + ERV
is related to body size and on average is 2.6dm 3 for males and 2.1dm 3 for females.
its higher in swimmers and divers
Its lower in older people and people who have lung disease such as emphysema
Vital capacity (VC)
volume of air that cannot be removed and remains in the lungs at the end of a maximum expiration
this air keeps the alveoli partly inflated and enables gas exchange to continue between breaths
Residual volume (RV)
volume breathed in by a maximum inspiration at the end of a normal inspiration
Inspiratory reserve volume (IRV)
volume breathed out by a maximum effort at the end of a normal expiration
Expiratory reserve volume (ERV)
On average 0.5dm 3
The volume of air inhaled or exhaled at each breath at rest.
Tidal volume (TV) description Type of lung capacity
Measuring your tidal volume and vital capacity (TV = the amount of air that is inhaled and exhaled in a normal breath) (VC= the maximum volume of air which can be expired following maximal inspiration)
For measuring tidal volume : Exhale into the tube, forcing air into the beaker and displacing a volume of water equal to the volume of air exhaled.
For measuring vital capacity : Exhale into the tube - this should be a normal exhalation followed by forcing as much air as possible from the lungs. .
Estimated VC: Males: 2.6dm 3 Females: 2.1dm 3 Female 2 Female 1 Male 2 Male 1 VC (dm 3 ) TV (dm 3 ) Student
Which factors affect lung volume? people living at low altitudes people living at high altitudes non-athletes professional athletes heavy smokers Non - smokers shorter people tall people females males Smaller volumes Larger volumes
Working out lung capacities Find spirograms from different types of people
2. During hyperventilation, breathing is very rapid with deep inhalations and exhalations. How would a graph of hyperventilation compare to normal breathing?
3. Emphysema reduces the flexibility of alveolar walls in the lungs so that they are unable to recoil normally from expiration. This results in an increased residual volume. How would a spirogram of a person with emphysema compare to that of a healthy person, assuming the same total lung capacity? How would emphysema affect the vital capacity?