Pulmonary Ventilation

Question 1

What is tachypnoea?

Answer 1

Elevated breathing rate

Question 2

What is hypoxemia?

Answer 2

Low oxygen blood levels

Question 3

What do lung volumes and capacities depend on?

Answer 3

Age, sex, height, and lung properties (like compliance, obstruction/ damage due to disease)

Question 4

What does TLC stand for?

Answer 4

Total lung capacity

Question 5

What does VC stand for?

Answer 5

Vital capacity

Question 6

What does FRC stand for?

Answer 6

Functional residual capacity

Question 7

What does IRV stand for?

Answer 7

Inspirating reserve volume

Question 8

What does VT (subscript T) stand for?

Answer 8

Tidal volume

Question 9

What does ERV stand for?

Answer 9

Expiratory reserve volume

Question 10

What does RV stand for?

Answer 10

Residual volume

Question 11

What does increased ventilation cause?

Answer 11

Increased partial pressure gradient (between alveoli and blood) and therefore increased gas exchange

Question 12

What happens to the partial pressure of O2 in the alveoli when ventilation increases?

Answer 12

Increase

Question 13

What happens to the partial pressure of CO2 in the alveoli when ventilation increases?

Answer 13

Decreases

Question 14

What does ventilation depend on?

Answer 14

Volume and rate of breathing

Question 15

What is minute volume?

Answer 15

The total volume of air inhaled in all breaths over one minute

Question 16

What is tidal volume?

Answer 16

The amount of air inhaled in each breath

Question 17

Is there any air left in lungs at the end of expiration?

Answer 17

Yes

Question 18

How much of each inspiration never gets to take part in gas exchange?

Answer 18

150ml ish

Question 19

What does alveolar ventilation correct for (that just ventilation doesnt)?

Answer 19

Volume of inspired air which doesnt take part in gas exchange

Question 20

What happens in inspiration?

Answer 20

Diaphragm contracts and thoracic cavity expands - the alveolar pressure decreases

Question 21

What happens in expiration?

Answer 21

Diaphragm relaxes (and lungs recoil). Thoracic cavity volume decreases and the alveolar pressure increases

Question 22

What happens at the end of expiration?

Answer 22

Alveolar pressure = atmospheric pressure so there is no net movement of air

Question 23

What causes the pleural cavity to resist changes in volume?

Answer 23

Scaled and fluid-filled

Question 24

What causes the pressure in the pleural cavity to be sub-atmospheric?

Answer 24

The opposing elastic recoil of the chest wall (outwards) and the lungs (inwards)

Question 25

What happens if there’s a negative pressure?

Answer 25

Less molecules per volume which generates a collapsing force

Question 26

What happens if there’s a positive pressure in the lungs?

Answer 26

Increased molecules per volume which generates an expanding force

Question 27

What is the movement of air in inspiration?

Answer 27

Respiratory muscles contract -> volume of thoracic cavity increases -> intrapleural pressure becomes more negative-> lungs expand, increasing volume -> alveolar pressure decreases below atmospheric pressure -> air moves down pressure gradient into alveoli, expanding the lungs

Question 28

What is the movement of air in expiration?

Answer 28

Respiratory muscles relax -> lungs recoil due to elastic fibres-> volume of thoracic cavity decreases -> intrapleural pressure increases-> lungs compress, decreasing volume -> alveolar pressure increases above atmospheric pressure -> air moves down pressure gradient into atmosphere, deflating the lungs

Question 29

What happens to intrapleural pressure during inspiration?

Answer 29

Becomes more negative due to the elastic properties of the lung generating increasing recoiling force

Question 30

What happens to alveolar pressure during inspiration?

Answer 30

As lungs expand, the increase in volume decreases Palv. As air enters the lungs, the pressure re-equilibriates once again as the increased concentration of gas molecules compensates for the increased volume

Question 31

What is an open pneumothorax?

Answer 31

If the outer pleural membrane is ruptured

Question 32

What is a closed pneumothorax?

Answer 32

If the inner pleural membrane or the lungs are ruptured

Question 33

Will one ruptured pleura impact the other?

Answer 33

No (probably…..)

Question 34

What happens if you get a pneumothorax?

Answer 34

The pressure gradient between the pleural cavity and surrounding environment causes air to enter until intrapleural pressure= atmospheric pressure

Question 35

What happens if air enters the pleura?

Answer 35

Pleural cavity volume increases( so lung volume decreases).