Pulmonary ventilation

Question 1

Hypoventilation

Answer 1

Excessive levels of CO2 within arterial blood

Question 2

Hyperventialtion

Answer 2

Reduced levels of CO2 within arterial blood

Question 3

Increasing rate of ventilation

Answer 3

Increases alveolar O2 partial pressure

Decreases alveolar CO2 partial pressure

Question 4

How does lung volume vary between individuals

Answer 4

By height, sex, age and specific respiratory diseases

Question 5

Total level of ventilation depends on

Answer 5

Both:
Volume of air inspires
Frequency of breathing

Question 6

why doesn’t total ventilation perfectly reflect the volume of air taking part in gas exchange

Answer 6

Exchange only takes place in alveoli, not airways.
Respiratory system does not completely empty, even at the end of a maximal forced expiration - residual volume of air is left in the lungs

Question 7

How does the respiratory system move air into and out of the lungs

Answer 7

Changing the alveolar pressure

Question 8

Move air into the lungs

Answer 8

Alveolar pressure must fall below atmospheric pressure

Question 9

Move air out of lungs

Answer 9

Alveolar pressure must rise above atmospheric pressure

Question 10

How are pressure changes achieved

Answer 10

Contraction/relaxation of respiratory muscles - Alters the volume of the thoracic cavity

Question 11

Visceral pleura

Answer 11

Inner

Lines each lung

Question 12

Parietal pleura

Answer 12

Outer

Lines the thoracic cavity

Question 13

How does the pleural cavity aid in breathing

Answer 13

Tissues attached to each pleura recoil in opposite directions due to their elastic properties
Stretching the sealed pleural cavity between them resulting in the pressure within the cavity being naturally sub-atmospheric

Question 14

Intrapleural pressure during inspiration

Answer 14

Intrapleural pressure becomes more negative - due to elastic properties of the lung generating increasing recoiling force

Question 15

Alveolar pressure during inspiration

Answer 15

Decreases alveolar pressure

Question 16

Pneumothorax

Answer 16

If either pleural membranes is ruptured.

Pressure gradient between the pleural cavity and the atmosphere will cause air to enter the pleural space

Question 17

Describe what happens to lung volume when the pleural membrane is ruptured

Answer 17

Pneumothorax until intrapleural pressure = atmospheric pressure
Entry of air = increase pleural cavity volume - lung volume DECREASES
This then reduces intrapleural pressure changes generated during inspiration preventing the lungs from expanding properly

Question 18

Function of the pleural cavity

Answer 18

1) Provide a fricitonless surface, aiding movement of the lungs
2) Ensure that changes in the volume of thoracic cavity result in corresponding changes in lung volume