Ventillation And Compliance

Question 1

What is the difference between pulmonary and alveolar ventilation?

Answer 1

Pulmonary ventilation is the total air movement into/out of the lungs
Alveolar ventilation if the fresh air getting to alveoli and therefore able for gas exchange

Alveolar ventilation is much more significant as it is the air that is involves in gas exchange whereas pulmonary ventilation is insignificant in functional terms)

Question 2

How do you work out the air to the alveoli?

Answer 2

Tidal volume - dead space

Question 3

How do you work out alveolar ventilation?

Answer 3

Air to alveoli X respiratory rate

Question 4

How do you measure total pulmonary ventilation?

Answer 4

Respiratory rate X tidal volume

Question 5

What percentage of air we inspire is trapped as anatomical dead space?

Answer 5

30% (150ml)

Question 6

What is the partial pressure of 02 when it reaches the blood?

Answer 6

100mmHg

Question 7

Why does their partial pressure of 02 decrease from 160mmHg to 100mmHg as it reaches our blood?

Answer 7

It decreases in pressure as it is moistened and diluted and saturated with water vapour

Question 8

At what week of gestation is surfactant produced and completed by?

Answer 8

Week 25

Completed by week 36

Question 9

In Usero what is surfactant synthesised by?

Answer 9

Thyroid hormones and cortisol

Question 10

Regarding spirometer;
What does dynamic measure?
What does static measure?

Answer 10

Dynamic - time taken to exhale a certain volume is measured

Static - the volume of air which can be exhaled is measured

Question 11

What percentage of the air we breath is oxygen?

Answer 11

21%

Question 12

What is the definition of partial pressure?.

Answer 12

The pressure of a gas in a mixture of gasses is equivalent to the percentage of that gas in the whole mixture times by the pressure of the whole gaseous mixture.

Question 13

During hyperventilation, what does p02 rise to and what does pC02 fall to?

Answer 13

P02 can rise to 120mmHg

PC02 can fall to 20mmHg

Question 14

During hyperventilation, what can P02 fall to and what can PC02 fall to?

Answer 14

P02 can fall to 30mmHg

PC02 can rise to 100mmHg

Question 15

Why is surfactant more effective in smaller alveoli compared to larger?

Answer 15

This is because surfactant molecules come closer together and therefore are more concentrated.
The pressure in smaller alveoli is higher than in larger therefore more surfactant molecules are required in order to equalise the pressure

Question 16

What prevents alveolar collapse?

Answer 16

Surfactant

Question 17

What is a normal FEV and FVC volume?

Answer 17

FEV = 4L
FVC = 5L
(Ratio = 80%)

Question 18

What is more affected in COPD - FEV or FVC?

Answer 18

Both decrease in COPD but FEV is reduced to a greater extent as the rate at which air is expelled is much slower

Question 19

What is the normal range of FEF?

Answer 19

25-75%

Question 20

What is forced exploratory flow (FEF)?

Answer 20

The average expired flow over the middle of an FVC