Ventilation And Compliance

Question 1

Volume of anatomical dead space

Answer 1

150ml

Question 2

TLC total lung capacity

Answer 2

5800ml

Question 3

ERV expiratory reserve volume

Answer 3

1100ml, big breath out after normal expiration

Question 4

TV tidal volume

Answer 4

500ml, normal breaths in and out

Question 5

IRV inspiratory reserve volume

Answer 5

3000ml, big breath on top of tidal volume (added is inspiratory capacity)

Question 6

FRC functional residual capacity

Answer 6

expiratory reserve plus residual volume

Question 7

RV residual volume

Answer 7

1200ml Always there

Question 8

FEV1

Answer 8

Forced expired volume in 1 second

Question 9

Pulmonary (minute) ventilation

Answer 9

Total air movement in and out of lungs

Question 10

Alveolar ventilation

Answer 10

Fresh air getting to alveoli

Question 11

PO2 change

Answer 11

160ml in air to 100ml in alveoli due to water and dead space and bc lungs aren’t empty

Question 12

How much air participates in gas exchange each breath

Answer 12

350ml (75%) due to dead space

Question 13

Hypoventilation

Answer 13

Not enough air getting into lungs, eg rapid but shallow breathing

Question 14

Hyperventilation

Answer 14

Too much air, eg slow but deep breathing

Question 15

Surfactant

Answer 15

Reduces surface tension on alveolar surface membrane due to air water interaction and attraction between water molecules. Therefore reduces tendency for lungs to collapse and increases lung compliance. More effective in smaller alveoli

Question 16

When does surfactant production happen and by what hormones is it stimulated

Answer 16

At 25 weeks until 36 weeks, stimulated by thyroid hormone and cortisol which reduce at end of pregnancy.

Question 17

IRDS

Answer 17

Infant respiratory distress due to lack of surfactant

Question 18

Compliance

Answer 18

Change in volume relative to change in pressure. Represents stretchability of lungs

Question 19

Emphysema

Answer 19

Loss of elastic tissue so expiration takes more effort

Question 20

Fibrosis

Answer 20

Inert fibrous tissue means effort of inspiration increases

Question 21

Location of lung affecting pressure volume

Answer 21

Alveoli at apex are stretched so need more pressure for less volume increase and vice versa

Question 22

Obstructive lung disease

Answer 22

Increased airway resistance eg asthma and COPD (chronic bronchitis is inflam, emphysema is destruction of alveoli and loss of elasticity). Slower exhalation so fev/FRC is reduced, tho FRC may also reduced and FVC is reduced but less than FEV is

Question 23

Restrictive lung disease

Answer 23

Loss of lung compliance eg fibrosis, IRDS, oedema, pnuemothorax. Ratio can be constant as rate of airflow and total volume both decrease. Ratio can also increase as a large proportion of volume can be exhaled in first second

Question 24

Spirometry types

Answer 24

Static is just exhalation volume, dynamic is time to exhale

Question 25

FEV1/FVC

Answer 25

Forced expiratory volume in 1 second divided by total exhalation

Question 26

FEF25-75

Answer 26

Forced expiratory flow, average over fvc, correlates with FEV1 but with more striking changes