Ventilation and Compliance Flashcards
What is tidal volume?
Volume during normal breathing- 500ml
What is expiratory reserve volume?
Air that can be forced out of the lungs but not expelled during normal breathing- 1100ml.
What is residual volume?
Air always present in the lungs- we cannot expel- 1200ml.
Inspiratory Reserve Volume?
Extra air we can inhale on top of tidal volume- 3000ml.
What does the term capacity mean?
This shows that it is two or more volumes combined.
Name two capacities that we can measure.
Inspiratory Capacity- normal exhale and big breath in. (TV + IRV = 3500ml)
Vital Capacity- breath out as much as possible then breath in as much as possible. ( VT + IRV+ ERV= 4600ml)
Which capacity can we not measure?
Functional Residual Capacity. Because it includes the RV which cannot be measured.
Total Lung Capacity
Vital Capacity + RV
Around 5l
What is FVC
Forced Vital Capacity
How much air can you expel. (peak flow)
What is FEV1
The proportion of your FVC that can be expelled within 1 second.
What is the difference between pulmonary ventilation and alveolar ventilation?
Pulmonary- total air in/out of lungs.
Alveolar- FRESH air reaching the alveoli.
Define Partial Pressure
The pressure of a gas in a mixture is equivalent to what percentage of the mixture it makes up multiplied by the pressure of the entire mixture.
Find the partial pressure of oxygen in air. Oxygen - 21% and air - 760mmHg
PP= 0.21*760
=160mmHg
Define Compliance
Shows the stretchiness of the lungs- but not how well they recoil (elasticity)
Give an example of low compliance.
Big decrease in Intra-pleural pressure, but only small increase in lung volume- Fibrosis.
What are the changes from Apex to Base?
Compliance increases from the apex to the base as gravity means more air is squeezed out.
Alveolar ventilation is higher at the base.
What are the two types of Lung Disease?
Obstructive VS Restrictive.
Define Obstructive
Increased airway resistance.
COPD, Asthma, Chronic Bronchitis, Emphysema
Define Restrictive
Loss of Lung compliance
Fibrosis, Oedema, Pneumothorax.
What is the normal ratio of FEV1/FVC?
Normal- 80% (4l/5l)
How is the ratio affected in Obstructive Lung Disease?
It is harder to force the air out so the ratio will be much less as will the volumes.
