Physiology 2.1 Flashcards
Describe the average total lung capacity in millilitres.
The average total lung capacity is about 6000 millilitres or just under 6 litres.
What is tidal volume in the context of breathing?
Tidal volume is the volume of air breathed in and out at rest, which is about 500 millilitres.
Define functional residual capacity in the context of the respiratory system.
Functional residual capacity is the volume of air left in the lungs at the end of a normal, relaxed expiration, which is about 2.3 litres.
How much additional air can be inspired with a really big breath, beyond the normal tidal volume?
About 3 litres or 3000 millilitres of air can be inspired as the inspiratory reserve volume.
Do we normally use our full lung capacity for breathing?
No, most of the time we breathe in about the middle of our lung capacity, leaving about 2.8 litres of air in the lungs at the end of a normal inspiration.
Describe the relationship between lung capacity and energy demand during exercise.
During exercise or when there is an increase in energy demand, we can increase our breathing capacity by using the inspiratory reserve volume and expiring additional air.
What is the typical volume of air breathed in and out during a normal breath at rest?
The typical volume of air breathed in and out during a normal breath at rest is about 500 millilitres, known as the tidal volume.
How much air is left inside the lungs at the end of a normal, relaxed expiration?
About 2.3 litres of air is left inside the lungs at the end of a normal, relaxed expiration, which is known as the functional residual capacity.
Describe the difference in lung capacity between a great big strapping bloke and a small, petite woman.
A great big strapping bloke may have a slightly bigger lung volume, while a small, petite woman may have a slightly smaller lung volume, but on average, the total lung capacity is around 6 litres.
Describe the expiratory reserve volume.
The extra air that can be expired with a bit more effort is called the expiratory reserve volume, which is approximately about a litre in volume on average.
What is vital capacity?
Vital capacity is the total amount of air that can be expired after a maximum inspiration, and it is often used in clinical respiratory physiology to measure lung function.
Define functional residual capacity.
Functional residual capacity is the amount of air left in the lungs at the end of a relaxed expiration.
How is residual volume defined?
Residual volume is the volume of air that remains in the lungs after a maximum expiratory effort, and it cannot be voluntarily expired.
Describe the role of residual volume.
Residual volume is important as it prevents the alveoli from collapsing and ensures that the air sacs remain expanded.
What is the difference between a volume and a capacity in respiratory physiology?
A volume is a single measurement of air, while a capacity involves two or more volumes added together.
Describe the importance of residual volume in the alveoli.
The residual volume prevents complete collapse of the alveoli, reducing the effort required to inflate them on the next inspiratory breath.
Define dead space in the context of the respiratory system.
Dead space refers to the volume of air in the upper airways that cannot participate in gas exchange, totaling about 150 milliliters.
How does residual volume contribute to gas exchange in the lungs?
Residual volume provides a volume of air that allows gas exchange to take place between breaths, ensuring continuous exchange of oxygen and carbon dioxide.
Do alveoli operate in a fully inflated state most of the time?
No, most of the time, alveoli operate in a partially inflated state, fluctuating between slightly and more partially inflated states within the tidal volume.
Describe the analogy used to explain the effort required to inflate the alveoli.
The analogy of blowing up a balloon is used, where it takes more effort to initially inflate it, but once it starts inflating, it becomes easier to inflate further.
What is the functional significance of dead space in the respiratory system?
Despite being a small proportion of total lung capacity, dead space (150ml) significantly impacts gas exchange, as it constitutes a large proportion of the tidal volume.
Describe the process of filling up the lungs to full capacity.
Taking an extra big breath and using inspiratory reserve volume allows the lungs to reach total lung capacity, filling up the alveoli to full capacity.
Define residual volume in the context of the respiratory system.
Residual volume refers to the volume of air in the lungs that cannot be voluntarily expired, no matter how hard one tries.
How does the large surface area in the nose contribute to comfortable breathing?
The large surface area in the nose is good at warming and moistening the air, making it much more comfortable to breathe.
Do the pleural cavities around the right and left lungs communicate with each other?
No, the pleural cavities around the right and left lungs are completely separate and do not communicate with each other.
Describe the role of the diaphragm in breathing.
The diaphragm is a key muscle for breathing, as it separates the thoracic cavity from the abdominal cavity and plays a significant role in the breathing process.
