Respiratory physiology

Question 1

Consider the following statements regarding functional residual capacity (FRC).
It can be measured using a spirometer

Answer 1

False. Measurement requires helium dilution of total body plethysmography.

Question 2

Consider the following statements regarding functional residual capacity (FRC).
It increases with age

Answer 2

True. FRC continues to increase with age as the elastic recoil of the lungs deteriorates

Question 3

Consider the following statements regarding functional residual capacity (FRC).
It is 10% lower in women than men of similar height

Answer 3

True

Question 4

Consider the following statements regarding functional residual capacity (FRC).
It is unaffected by pregnancy

Answer 4

False. As the gravid uterus pushes the diaphragm cephalad, FRC is reduced, as is the extra weight of the breast on the chest wall.

Question 5

Consider the following statements regarding functional residual capacity (FRC).
It is equal to residual volume + expiratory reserve volume

Answer 5

True

Question 6

Consider the following statements regarding physiological dead space
It is smaller than anatomical dead space

Answer 6

False. Physiological dead space = anatomical dead space + alveolar dead space.

Question 7

Consider the following statements regarding physiological dead space
It is increased by pulmonary embolism

Answer 7

True

Question 8

Consider the following statements regarding physiological dead space
It can be increased if tidal volume drops despite an increase in respiratory rate

Answer 8

True. A smaller proportion of the tidal volume reaches the alveoli.

Question 9

Consider the following statements regarding physiological dead space
It is measured using Fowler’s method

Answer 9

False. Fowler’s method is used to measure anatomical dead space. The Bohr equation calculates physiological dead space.

Question 10

Consider the following statements regarding physiological dead space
Calculation requires knowledge of arterial partial pressure of CO2

Answer 10

True. The Bohr equation requires PACO2 and PECO2 to calculate the dead space to tidal volume ratio.

Question 11

Consider the following statements regarding functional residual capacity.
Helium dilution gives a larger estimation than body plethysmography

Answer 11

False. Plethysmography gives a larger, more accurate estimation of FRC, especially in diseased lungs where gas trapping may occur.

Question 12

Consider the following statements regarding functional residual capacity.
Changes in FRC can affect pulmonary vascular resistance

Answer 12

True. Normally, FRC is at the point where PVR is least, but a decrease in FRC may cause an increase in PVR.

Question 13

Consider the following statements regarding functional residual capacity.
FRC increases in asthma

Answer 13

True. Obstructive lung disease can cause gas trapping.

Question 14

Consider the following statements regarding functional residual capacity.
FRC increases with PEEP

Answer 14

True

Question 15

Consider the following statements regarding functional residual capacity.
FRC increases following administration of neuromuscular blocking agents

Answer 15

False. Anything that decreases muscle tone of the diaphragm and intercostal muscles will reduce FRC.

Question 16

Consider the following statements regarding dead space.

It increases while snorkelling

Answer 16

True. The snorkel acts as an increase in the transporting airway.

Question 17

Consider the following statements regarding dead space.

If increased, it leads to hypoxia

Answer 17

False. Dead space per se is not a cause of hypoxia.

Question 18

Consider the following statements regarding dead space.

It accounts for the difference in arterial and expired CO2 concentrations

Answer 18

True

Question 19

Consider the following statements regarding dead space.

It increases with bronchodilatation and neck extension

Answer 19

True

Question 20

Consider the following statements regarding dead space.

Alveolar dead space decreases with age

Answer 20

False

Question 21

The functional residual capacity

is increased in the obese

Answer 21

False

Question 22

The functional residual capacity

is approx 10% higher in men than women

Answer 22

False

Question 23

The functional residual capacity

falls with general anaesthesia

Answer 23

True

Question 24

The functional residual capacity

increases when changing from supine to standing

Answer 24

True

Question 25

The functional residual capacity | falls with increasing age

Answer 25

False

Question 26

Vital capacity is the volume or air expired from full inspiration to full expiration

Answer 26

True

Question 27

Vital capacity increases gradually with age in adults

Answer 27

False

Question 28

Vital capacity is greater in men than women of a similar age and height

Answer 28

True

Question 29

Vital capacity is equal to the sum of the inspiratory and expiratory reserve volumes

Answer 29

False

Question 30

Vital capacity may be measured by spirometry

Answer 30

True

Question 31

Closing Capacity is larger than functional reserve capacity

Answer 31

False

Question 32

Closing Capacity may be determined by single breath N2 curve following deep breath of O2

Answer 32

False

Question 33

Closing Capacity is high in young children and decreases progressively with age

Answer 33

False

Question 34

Closing Capacity if high may be responsible for arterial hypoxaemia

Answer 34

True

Question 35

Closing Capacity is unaffected by bronchomotor tone

Answer 35

False

Question 36

Closing volume increases with age

Answer 36

True

Question 37

Closing volume decreases with anaesthesia

Answer 37

True

Question 38

Closing volume is increased in the upright position

Answer 38

false

Question 39

Closing volume is increased in obesity

Answer 39

false

Question 40

Closing volume can be measured using single breath nitrogen technique

Answer 40

True

Question 41

FRC can be measured using Helium wash in

Answer 41

True

Question 42

FRC can be measured using nitrogen was out

Answer 42

True

Question 43

FRC can be measured using body plethysmography

Answer 43

True

Question 44

FRC can be measured using spirometry

Answer 44

false

Question 45

FRC can be measured using intra-oesophaeal balloon

Answer 45

False

Question 46

Surfactant is a mucopolypeptide

Answer 46

False

Question 47

Surfactant causes a decrease in surface tension

Answer 47

true

Question 48

Surfactant equilibrates surfae tension for different sized alveoli

Answer 48

true

Question 49

Surfactant causes an increase in compliance

Answer 49

true

Question 50

Surfactant production is reduced after a prolonged reduction in pulmonary blood flow

Answer 50

True

Question 51

pulmonary surfactant is a mixture of phospholipids and proteins

Answer 51

True

Question 52

pulmonary surfactant causes and increase in chest wall compliance

Answer 52

false

Question 53

pulmonary surfactant prevents transudation or fluid from the blood into the alveoli

Answer 53

true

Question 54

pulmonary surfactant deficiencies in babies born to diabetic mothers is due to fetal hyperinulinism

Answer 54

true

Question 55

pulmonary surfactant concentration per unit area is directly proportional to surface tension

Answer 55

false

Question 56

When the V/Q ratio of a lung unit increases the alveolar PO2 rises

Answer 56

true

Question 57

When the V/Q ratio of a lung unit increases the alveolar CO2 rises

Answer 57

False

Question 58

When the V/Q ratio of a lung unit increases end capillary PO2 rises

Answer 58

true

Question 59

When the V/Q ratio of a lung unit increases arterial PO2 increases

Answer 59

True

Question 60

When the V/Q ratio of a lung unit increases hypoxic pulmonary vasoconstriction will compensate for any change in gas exchange

Answer 60

false

Question 61

The distribution of ventilation of an upright subject is related to regional airways diameters

Answer 61

True

Question 62

The distribution of ventilation of an upright subject is related to regional differences in compliance

Answer 62

True

Question 63

The distribution of ventilation of an upright subject is related to inspired O2 concentration

Answer 63

false

Question 64

The distribution of ventilation of an upright subject is related to gravitational forces in the lung

Answer 64

True

Question 65

The distribution of ventilation of an upright subject is related to intrathoracic pressure

Answer 65

True

Question 66

In an awake, healthy individual in the lateral position, the dependant lung has less ventilation

Answer 66

false

Question 67

In an awake, healthy individual in the lateral position, the dependant lung has more perfusion

Answer 67

true

Question 68

In an awake, healthy individual in the lateral position, the V/Q ratio is higher in the dependant lung

Answer 68

false

Question 69

In an awake, healthy individual in the lateral position, the PACO2 is lower in the lower lung

Answer 69

false

Question 70

In an awake, healthy individual in the lateral position, the PAO2 is higher in the lower lung

Answer 70

false

Question 71

The following vessels are important in the physiological shunt Bronchial veins

Answer 71

true

Question 72

The following vessels are important in the physiological shunt Thebesian veins

Answer 72

true

Question 73

The following vessels are important in the physiological shunt coronary sinus

Answer 73

false

Question 74

The following vessels are important in the physiological shunt ductus venosus

Answer 74

false

Question 75

The following vessels are important in the physiological shunt azygous veins

Answer 75

false

Question 76

An area in the lung with increased V/Q ratio represents dead space

Answer 76

true

Question 77

An area in the lung with increased V/Q ratio represents shunt

Answer 77

false

Question 78

An area in the lung with increased V/Q ratiois responsible for a decrease in the PAO2 with no change in PACO2

Answer 78

false

Question 79

An area in the lung with increased V/Q ratio will cause a degree of hypoxia

Answer 79

false

Question 80

An area in the lung with increased V/Q ratio may be compensated for by an increase minute ventilation

Answer 80

true

Question 81

A pressure volume curve can be used for measuring the owrk of breathing

Answer 81

true

Question 82

A pressure volume curve can be used for measuring functional residual capacity

Answer 82

false

Question 83

A pressure volume curve can be used for measuring anatomical dead space

Answer 83

false

Question 84

A pressure volume curve can be used for measuring compliance

Answer 84

true

Question 85

A pressure volume curve can be used for measuring respiratory quotient

Answer 85

false

Question 86

body plethysmography can be used to measure compliance

Answer 86

true

Question 87

body plethysmography can be used to measure work of breathing

Answer 87

true

Question 88

body plethysmography can be used to measure gas exchange

Answer 88

false

Question 89

body plethysmography can be used to measure airway resistance

Answer 89

true

Question 90

body plethysmography can be used to measure FEV1

Answer 90

false

Question 91

concerning lung volumes and capacities the total volume of both lungs is the vital capacity

Answer 91

false

Question 92

concerning lung volumes and capacities closing capacity is the sum of the closing volume and the FRC

Answer 92

false

Question 93

concerning lung volumes and capacities the volume which may be forcibly exhaled in 1 sec is greater than 85% of the vital capacity

Answer 93

false

Question 94

concerning lung volumes and capacities the FRC can be measured with a spirometer

Answer 94

false

Question 95

concerning lung volumes and capacities the sum of the insp reserve volume and the exp reserve volume is the vital capacity

Answer 95

false

Question 96

Alveolar dead space exceeds tidal volume at rest

Answer 96

false

Question 97

Alveolar ventilation decreases as tidal volume increases

Answer 97

false

Question 98

Alveolar partial pressure of water vapour exceeds that of carbon dioxide

Answer 98

true

Question 99

Alveolar patial pressure of O2 falls within an increase in physiological dead space

Answer 99

false

Question 100

Alveolar O2 uptake exceeds alveolar carbon dioxide output

Answer 100

true

Question 101

Breathing spontaneously in the lateral position: | Perfusion is greater in the dependent lung

Answer 101

True.

Question 102

Breathing spontaneously in the lateral position: | Ventilation is decreased in the uppermost lung

Answer 102

True.

Question 103

Breathing spontaneously in the lateral position: | V/Q is higher in the dependent lung

Answer 103

False. In the awake adult, ventilation and perfusion are greater in the lower (dependent) lung although perfusion is slightly better than ventilation and so V/Q < 1.

Question 104

Breathing spontaneously in the lateral position: | Dependent lung has a lower PO2

Answer 104

True. V/Q is < 1, ie there is a degree of shunt. In areas of shunt alveolar gas tends toward mixed venous so PAO2 is low and PACO2 slighlty raised.

Question 105

Breathing spontaneously in the lateral position: | Non-dependent lung has a higher PCO2

Answer 105

False. In the non-dependent lung V/Q > 1, ie a degree of dead space. Alveolar gas now tends toward inspired gas and so PO2 is raised but PCO2 is low.

Question 106

FRC can be measured using: | Body plethysmography

Answer 106

True

Question 107

FRC can be measured using: | Nitrogen wash-out

Answer 107

True

Question 108

FRC can be measured using: | Spirometry

Answer 108

False

Question 109

FRC can be measured using: | Helium wash-in

Answer 109

True

Question 110

FRC can be measured using: | Intra-oesophageal balloon

Answer 110

False. Intra-oesophageal balloons are used to measure intra-pleural pressure.

Question 111

Concerning 2,3, DPG: | It binds the beta chains of deoxyhaemoglobin

Answer 111

True.

Question 112

Concerning 2,3, DPG: | It is formed from a product of glycolysis

Answer 112

True. 2,3-DPG is formed in red blood cells from phosphoglyceraldehyde, a product of glycolysis.

Question 113

Concerning 2,3, DPG: | An increased concentration increases oxygen utilisation by cells

Answer 113

True. 2,3 DPG shifts the O2 dissociation curve to the right, reducing oxygen binding to haemoglobin and thus increasing oxygen availability for tissue utilization.

Question 114

Concerning 2,3, DPG: | Its red cell concentration is increased by circulating thyroid hormones

Answer 114

True. Thyroid hormones, along with growth hormone and angrogens increase 2,3,DPG concentration.

Question 115

Concerning 2,3, DPG: | Is strongly bound by fetal haemoglobin

Answer 115

False. Fetal Hb does not contain beta chains.

Question 116

Dipalmitoylphosphatidylcholine: | Is a mucopolypeptide

Answer 116

False. It is a phospholipid, found in lung surfactant.

Question 117

Dipalmitoylphosphatidylcholine: | Causes an increase in surface tension

Answer 117

False. Surfactants role is to decrease surface tension.

Question 118

Dipalmitoylphosphatidylcholine: | Causes an increase in chest wall compliance

Answer 118

False. It increases lung compliance, not chest wall compliance.

Question 119

Dipalmitoylphosphatidylcholine: | Production is reduced in low cardiac output states

Answer 119

True. As it is derived from free fatty acids carried in the blood stream.

Question 120

Dipalmitoylphosphatidylcholine: | Maintains the same surface tension for different sized alveoli

Answer 120

False. It is more effective at reducing surface tension in small alveoli. This reduces the effect of Laplace's law, which would otherwise cause small alveoli to collape.

Question 121

Peripheral chemoreceptors: | Are found in the carotid sinus

Answer 121

False. They are located in the carotid and aortic bodies.

Question 122

Peripheral chemoreceptors: | Are downregulated in the presence of chronic lung disease

Answer 122

False. Central chemoreceptors in the medulla respond to a rise in PaCO2 and CSF pH.

Question 123

Peripheral chemoreceptors: | Are stimulated by elevated levels of carboxyhaemoglobin

Answer 123

False.

Question 124

Peripheral chemoreceptors: | Give rise to increased afferent signals when PaO2 falls below 13 kPa

Answer 124

True. The carotid body is the prime O2 sensory organ.

Question 125

Peripheral chemoreceptors: | Maintain PaCO2 within the range 4.5-6.0 kPa

Answer 125

False. see part D.

Question 126

Carbon dioxide: | Freely diffuses across the blood : brain barrier

Answer 126

True. Unlike H+ ions and HCO3-.

Question 127

Carbon dioxide: | Is lagely transported unchanged

Answer 127

False. Most is transported as bicarbonate. Around 5% is transported unchanged in the blood.

Question 128

Carbon dioxide: | Gives rise to the same pH change in CSF as it does in blood

Answer 128

False. pH changes are greater in the CSF due to the lack of buffers.

Question 129

Carbon dioxide: | Transport by haemoglobin is inhibited by rising oxygen saturation

Answer 129

True. By the Haldane effect.

Question 130

Carbon dioxide: | Has direct sympathomimetic activity

Answer 130

False. But it does increase activation of the sympathetic system.

Question 131

Pulmonary blood flow: | Is normally less than the cardiac output

Answer 131

True. A small proportion of the cardiac output will be anatomical shunt.

Question 132

Pulmonary blood flow: | Has a mean arterial pressure of 25-30 mmHg

Answer 132

False. Mean pressure is around 15 mmHg. 25 -30mmHg would be the systolic pressure.

Question 133

Pulmonary blood flow: | In West zone 1, occurs mainly during diastole

Answer 133

False. In West zone 1 pA>pa>pv therefore the pulmonary capillary is completely compressed by by the alveolus ceasing. This results in a very high V/Q ratio

Question 134

Pulmonary blood flow: | Of 6000 ml/min with a minute ventilation of 4000 ml/min suggests the presence of a shunt

Answer 134

True. As perfusion is significantly greater than ventilation.

Question 135

Pulmonary blood flow: | Is maximal in zone 2

Answer 135

False. It is maximal in zone 3.

Question 136

Restrictive lung disease is characterized by: | A fall in FEV1

Answer 136

True. Pulmonary function tests generally reveal a decrease in both FEV1 and FVC with a normal FEV1/FVC ratio.

Question 137

Restrictive lung disease is characterized by: | A fall in arterial PO2

Answer 137

True. A fall in FRC causes alveolar collapse with a resultant shunt.

Question 138

Restrictive lung disease is characterized by: | A fall in FEV1/FVC ratio

Answer 138

False.

Question 139

Restrictive lung disease is characterized by: | Carbon dioxide retention

Answer 139

False.

Question 140

Restrictive lung disease is characterized by: | A fall in vital capacity

Answer 140

True. As does TLC and FRC.

Question 141

During intermittent positive pressure ventilation: | Mean intrathoracic pressure will be lower than during spontaneous breathing

Answer 141

False.

Question 142

During intermittent positive pressure ventilation: | Right ventricular filling falls compared with spontaneous ventilation

Answer 142

True. Which will reduce cardiac output.

Question 143

During intermittent positive pressure ventilation: | PEEP will reinflate collapsed alveoli

Answer 143

False. PEEP will prevent collapse, but would not normally be high enough to re-inflate collapsed lung.

Question 144

During intermittent positive pressure ventilation: | Right ventricular workload may increase

Answer 144

True. PVR may rise during IPPV due to hyperinflation or alveolar collpase (PVR is lowest at FRC and rises above or below this).

Question 145

During intermittent positive pressure ventilation: | Left ventricular workload may decrease

Answer 145

True. IPPV reduces LV afterload by decreasing LV cavity size and transluminal wall tension.

Question 146

Hyperventilation produces: | Muscle spasm

Answer 146

True. Alkalosis decreases the proportion of ioised calcium, causing tetany.

Question 147

Hyperventilation produces: | A raised pH

Answer 147

True.

Question 148

Hyperventilation produces: | Decreased cerebral blood flow

Answer 148

True.

Question 149

Hyperventilation produces: | Peripheral vasodilatation

Answer 149

False. Hypocarbia causes vasoconstriction by a direct effect.

Question 150

Hyperventilation produces: | Increased cardiac output

Answer 150

False. Hypercarbia causes an increase in cardiac output due to increased sympathetic activity. The direct effect of vasoconstriction from hypocarbia will reduce cardiac output.