Respiratory 2

Question 1

Explain perfusion limited and diffusion limited transfer of gases in the alveolus
2021 march
Appears to be unique question

X and X are the two main processes which govern the rate of alveolar-capillary gas transfer

Answer 1

Explain perfusion limited and diffusion limited transfer of gases in the alveolus
2021 march
Appears to be unique question

• Diffusion and perfusion are the two main processes which govern the rate of alveolar-capillary gas transfer

-deranged

Question 2

Explain perfusion limited and diffusion limited transfer of gases in the alveolus
2021 march
Appears to be unique question

• Diffusion -limited gas exchange:

Answer 2

Explain perfusion limited and diffusion limited transfer of gases in the alveolus
2021 march
Appears to be unique question

o Exchange where the rate of gas uptake in the capillary is determined by the rate of diffusion across the blood-gas barrier
 The rate of diffusion from alveolus to blood is very slow
 For all of the length of the capillary, the gradient between the alveolus and the blood remains high
 An increase in the capillary blood flow rate will have minimal effect on gas uptake
 An increase in the partial pressure gradient between the alveolus and the capillary will increase the rate of difffusion
 An example of a diffusion-limited gas is carbon monoxide

-deranged

Question 3

Explain perfusion limited and diffusion limited transfer of gases in the alveolus
2021 march
Appears to be unique question

• Perfusion-limited gas exchange

Answer 3

Explain perfusion limited and diffusion limited transfer of gases in the alveolus
2021 march
Appears to be unique question

• Perfusion-limited gas exchange
  o Exchange where the rate of gas uptake in the capillary is determined by capillary blood flow:
   The rate of gas diffusion into the capillary is very rapid
   Equilibration between the alveolus and capillary occurs shortly after blood enters the alveolar capillary
   For most of its length, the capillary blood is fully saturated with the gas
   Increasing the blood flow rate will increase the rate of total gas uptake, until the capillary transit time is faster than the gas diffusion time
   Increasing the partial pressure gradient between the alveolus and capillary does not significantly increase the rate of gas uptake into the blood if the blood flow remains the same (even more so in the case of oxygen)
   Oxygen, carbon dioxide and nitrous oxide are perfusion-limited.

-deranged

Question 4

Explain perfusion limited and diffusion limited transfer of gases in the alveolus
2021 march
Appears to be unique question

• Examiner comment

Answer 4

Explain perfusion limited and diffusion limited transfer of gases in the alveolus
2021 march
Appears to be unique question

College Answer
This question required detail on those factors affecting gas exchange at the level of the alveolus. A description of the components of the Fick equation was expected - and how this related to oxygen and carbon dioxide transfer at the alveolar capillary membrane. The rapid rate of equilibration (developed tension) was the limiting factor in of blood/alveolar exchange that rendered some gases perfusion limited (examples - N2O, O2 under usual conditions but not all) and the slower rate of others diffusion limited (examples CO and O2 under extreme conditions e.g., exercise, altitude). Estimates of time taken for each gas to equilibrate relative to the time taken for the RBC to travel across the interface was also expected for full marks. CO2 despite rapid equilibration and higher solubility was correctly described as perfusion limited (unless in disease states). Better answers described CO2 as ventilation limited. Some answers also correctly included the component of interaction with the RBC and haemoglobin. Ventilation/perfusion inequalities over the whole lung were not asked for and scored no marks.

-deranged

Question 5

2020 aug, 2017 aug, 2017 march, 2015 aug, 2010 aug

2020 aug Q2
Define functional residual capacity (10% marks). Outline the functions (70% marks) of the functional residual capacity and the factors affecting it (20% marks).

The FRC is:

Answer 5

The volume of gas present in the lung at end expiration during tidal breathing
It is composed of ERV and RV
This is usually 30-35 ml/kg, or 2100-2400ml in a normal sized person
It represents the point where elastic recoil force of the lung is in equilibrium with the elastic recoil of the chest wall, i.e. where the alveolar pressure equilibrates with atmospheric pressure.

deranged

Question 6

2020 aug, 2017 aug, 2017 march, 2015 aug, 2010 aug

2020 aug Q2
Define functional residual capacity (10% marks). Outline the functions (70% marks) of the functional residual capacity and the factors affecting it (20% marks).

what equals
elastic recoil force of the lung is in equilibrium with the elastic recoil of the chest wall

Answer 6

FRC
The volume of gas present in the lung at end expiration during tidal breathing
It is composed of ERV and RV
This is usually 30-35 ml/kg, or 2100-2400ml in a normal sized person
It represents the point where elastic recoil force of the lung is in equilibrium with the elastic recoil of the chest wall, i.e. where the alveolar pressure equilibrates with atmospheric pressure.

deranged

Question 7

2020 aug, 2017 aug, 2017 march, 2015 aug, 2010 aug

2020 aug Q2
Define functional residual capacity (10% marks). Outline the functions (70% marks) of the functional residual capacity and the factors affecting it (20% marks).

Functions of the FRC are:

Answer 7

Functions of the FRC are:
* Oxygen reservoir
o FRC maintains an oxygen reserve which maintains oxygenation between breaths
o This prevents rapid changes in alveolar oxygen tension and arterial oxygen content
.
* Maintenance of small airway patency
o At FRC, the small airway resistance is at its lowest.
o Where closing capacity is greater than the FRC, gas trapping and atelectasis can develop because of small airway collapse
.
* Optimisation of pulmonary vascular resistance
o At FRC, pulmonary vascular resistance is minimal
o The RV afterload and pulmonary blood flow are therefore optimal
.
* Optimisation of respiratory workload
o At FRC, lung compliance is maximal
o The work of breathing required to inflate the lung from FRC is minimum

deranged

Question 8

2020 aug, 2017 aug, 2017 march, 2015 aug, 2010 aug

2020 aug Q2
Define functional residual capacity (10% marks). Outline the functions (70% marks) of the functional residual capacity and the factors affecting it (20% marks).

At FRC, the small airway resistance is at its X

Answer 8

• Maintenance of small airway patency
  o At FRC, the small airway resistance is at its lowest.
  o Where closing capacity is greater than the FRC, gas trapping and atelectasis can develop because of small airway collapse
  .

deranged

note; need a trick to remember, I guess as alveloi fill up they would push on small airways and compress them, thus when the lungs are not filled with air, airways would have less pushing on them and thus lower resistance

Question 9

2020 aug, 2017 aug, 2017 march, 2015 aug, 2010 aug

2020 aug Q2
Define functional residual capacity (10% marks). Outline the functions (70% marks) of the functional residual capacity and the factors affecting it (20% marks).

o At FRC, pulmonary vascular resistance is

Answer 9

• Optimisation of pulmonary vascular resistance
  o At FRC, pulmonary vascular resistance is minimal
  o The RV afterload and pulmonary blood flow are therefore optimal
  .

deranged

note; need a trick to remember, as the lungs will up with air the alveoli compress the blood vessels, sort of like at the top of the lungs where alveoli pressure is higher than arterial and vascular and thus there is more dead space

Question 10

2020 aug, 2017 aug, 2017 march, 2015 aug, 2010 aug

2020 aug Q2
Define functional residual capacity (10% marks). Outline the functions (70% marks) of the functional residual capacity and the factors affecting it (20% marks).

At FRC, lung compliance is X

Answer 10

• Optimisation of respiratory workload
  o At FRC, lung compliance is maximal
  o The work of breathing required to inflate the lung from FRC is minimum

deranged

note; need a trick to remember, , this makes sense alveloli are half full and thus can easily be increased, where if they were already full it would be harder to fill them

Question 11

2020 aug, 2017 aug, 2017 march, 2015 aug, 2010 aug

2020 aug Q2
Define functional residual capacity (10% marks). Outline the functions (70% marks) of the functional residual capacity and the factors affecting it (20% marks).

Factors affecting the FRC are:

Answer 11

Factors affecting the FRC are:
* Factors that increase FRC:
o Male sex
o Large body size
o Emphysema
o PEEP or auto-PEEP
o Open chest
o Erect body position
.
* Factors that decrease FRC:influence lung size (height and gender) - larger lung size increases FRC
o Female sex
o Small stature
o ARDS
o increased intraabdominal pressure
o pregnancy, obesity
o anaesthesia and paralysis
o supine position

deranged

Question 12

2020 aug, 2017 aug, 2017 march, 2015 aug, 2010 aug

2017 aug Q24
What is functional residual capacity and describe how it is measured

• FRC is usually measured by one of three methods:

Answer 12

• FRC is usually measured by one of three methods:

o Body plethysmography
o Inert gas dilution
o Nitrogen washout

deranged

Question 13

2020 aug, 2017 aug, 2017 march, 2015 aug, 2010 aug

2017 aug Q24
What is functional residual capacity and describe how it is measured

summary slide for equations

Answer 13

• FRC is usually measured by one of three methods:

o Body plethysmography
o Inert gas dilution
o Nitrogen washout

deranged

Body plethysmography requires more complex calculations of P1V1= P2V2 (Boyles Law)

note; important equation ; C1V1=C2V2 where V2 = V1+FRC.
note; super important that inert gasses and nitrogen washout use the same formula

2015 aug, - examiner comment
This question requested a definition AND a description of measurement (one method if correctly discussed could and did generate a pass mark) although additional marks were awarded if multiple measurement methods were mentioned or described. Detailed descriptions of the factors effecting FRC and its functions were NOT requested and scored no marks. “Fowlers method” uses 100% oxygen and nitrogen analysis to calculate anatomical dead space - NOT
FRC - so scored no marks. Both Helium dilution and nitrogen washout (with 100%oxygen) enable calculation of FRC using C1V1=C2V2 where V2 = V1+FRC. Body plethysmography requires more complex calculations of P1V1= P2V2 (Boyles Law) applied twice = for the box and then the lung. Few candidates had a clear understanding of this method. Most answers did not demonstrate the depth of understanding of the measurement techniques
that was required to score highly.

Question 14

2020 aug, 2017 aug, 2017 march, 2015 aug, 2010 aug

2017 aug Q24
What is functional residual capacity and describe how it is measured

o Body plethysmography

Answer 14

• FRC is usually measured by one of three methods:

o Body plethysmography
 The subject and the equipment are all confined in a rigid box which contains a known gas volume.
 As the subject exhales:
 Intrathoracic volume decreases, which means the volume of the box increases (as the walls are rigid and there is a finite volume shared by the chest and the box).
 Intrathoracic pressure increases, and therefore box pressure decreases proportionally.
 Though the amount of the gas in the chest is unknown, we know that (according to Boyle’s law) the product of pressure and volume in the chest should be the same as the product of volume and pressure in the box.
 The volume in the box, the pressure in the box and the pressure in the chest are all known variables at this point, leaving the volume of intrathoracic gas as the last unknown

deranged

Question 15

2020 aug, 2017 aug, 2017 march, 2015 aug, 2010 aug

2017 aug Q24
What is functional residual capacity and describe how it is measured

o Inert gas dilution

Answer 15

• FRC is usually measured by one of three methods:

o Inert gas dilution
 A subject is given a known volume (V1) of an inert tracer gas (eg. helium) which has a known concentration (C1)
 The inert tracer gas is inhaled and mixes with intrathoracic as, whcih dilutes the racer.
 The patient then exhales this gas mixture, and the exhaled tracer concentration (C2) can be measured
 From this, the intrathoracic gas volume (V2) can be calculated from the equation:

C1 × V1 = C2 × (V1 + V2)

deranged

note; in the examiner comment its C1V1=C2V2 where V2 = V1+FRC.

note; I helium is a type of inert gas

Question 16

2020 aug, 2017 aug, 2017 march, 2015 aug, 2010 aug

2017 aug Q24
What is functional residual capacity and describe how it is measured

o Nitrogen washout

Answer 16

• FRC is usually measured by one of three methods:

o Nitrogen washout
 The subject is made to breathe 100% FiO2.
 The nitrogen concentration of exhaled gas is measured
 As the intrathoracic nitrogen content approaches zero, the total exhaled nitrogen voume can be calculated from its concentration in the exhaled gas
 The intrathoracic gas volume can then be calculated from the total volume of exhaled nitrogen gas and the nitrogen concentration of the first breath

deranged

Question 17

2020 aug, 2017 aug, 2017 march, 2015 aug, 2010 aug

2017 aug Q24
What is functional residual capacity and describe how it is measured

2015 aug, exact same question and deranged answer same

examiner comment

Answer 17

What is functional residual capacity and describe how it is measured

2017 aug Q24
Most candidates could state 2 methods of measuring FRC. Some candidates (especially for
nitrogen wash out) failed to provide enough information e.g. statements such as “if the amount
of nitrogen is measured then FRC can be derived” were insufficient to score many marks.

2015 aug,
This question requested a definition AND a description of measurement (one method if correctly discussed could and did generate a pass mark) although additional marks were awarded if multiple measurement methods were mentioned or described. Detailed descriptions of the factors effecting FRC and its functions were NOT requested and scored no marks. “Fowlers method” uses 100% oxygen and nitrogen analysis to calculate anatomical dead space - NOT
FRC - so scored no marks. Both Helium dilution and nitrogen washout (with 100%oxygen) enable calculation of FRC using C1V1=C2V2 where V2 = V1+FRC. Body plethysmography requires more complex calculations of P1V1= P2V2 (Boyles Law) applied twice = for the box and then the lung. Few candidates had a clear understanding of this method. Most answers did not demonstrate the depth of understanding of the measurement techniques
that was required to score highly.

note; important equation ; C1V1=C2V2 where V2 = V1+FRC.

note; super important that inert gasses and nitrogen washout use the same formula

Question 18

2020 aug, 2017 aug, 2017 march, 2015 aug, 2010 aug

2017 aug Q24
What is functional residual capacity and describe how it is measured

2015 aug, exact same question and deranged answer same

What is fowlers method??

Answer 18

What is functional residual capacity and describe how it is measured

2015 aug, - examiner comment
This question requested a definition AND a description of measurement (one method if correctly discussed could and did generate a pass mark) although additional marks were awarded if multiple measurement methods were mentioned or described. Detailed descriptions of the factors effecting FRC and its functions were NOT requested and scored no marks. “Fowlers method” uses 100% oxygen and nitrogen analysis to calculate anatomical dead space - NOT
FRC - so scored no marks. Both Helium dilution and nitrogen washout (with 100%oxygen) enable calculation of FRC using C1V1=C2V2 where V2 = V1+FRC. Body plethysmography requires more complex calculations of P1V1= P2V2 (Boyles Law) applied twice = for the box and then the lung. Few candidates had a clear understanding of this method. Most answers did not demonstrate the depth of understanding of the measurement techniques
that was required to score highly.

Question 19

2017 march Q8
Describe the physiological consequences of decreasing the functional residual capacity (FRC) in an adult by 1 litre.

exact same as 2010 aug

Effects of decreased FRC on lung mechanics

Answer 19

Effects of decreased FRC on lung mechanics

• Decreased lung compliance: the decreasing size of alveoli at lower FRCs results in a decreased rate of
• Increased airway resistance: because airway resistance is relatively low at FRC, it is going to increase as the FRC decreases. This is due to the fact that collapsing alveoli tend to stop providing the radial traction which keeps the small airways open.
• Increased work of breathing, owing to the above.
• Decreased tidal volume and increased respiratory rate, due to decreased lung compliance
• Decreased tolerance of position changes, i.e. with a low baseline FRc in the upriht position a patient will not tolerate being supine for very long, as the FRC will drop yet further

deranged

Question 20

2017 march Q8
Describe the physiological consequences of decreasing the functional residual capacity (FRC) in an adult by 1 litre.

exact same as 2010 aug

X tidal volume and X respiratory rate, due to X

Answer 20

Effects of decreased FRC on lung mechanics

• Decreased lung compliance: the decreasing size of alveoli at lower FRCs results in a decreased rate of
• Increased airway resistance: because airway resistance is relatively low at FRC, it is going to increase as the FRC decreases. This is due to the fact that collapsing alveoli tend to stop providing the radial traction which keeps the small airways open.
• Increased work of breathing, owing to the above.
• Decreased tidal volume and increased respiratory rate, due to decreased lung compliance
• Decreased tolerance of position changes, i.e. with a low baseline FRc in the upriht position a patient will not tolerate being supine for very long, as the FRC will drop yet further

deranged

Question 21

2017 march Q8
Describe the physiological consequences of decreasing the functional residual capacity (FRC) in an adult by 1 litre.

exact same as 2010 aug

Effect of decreased FRC on shunt

Answer 21

Effect of decreased FRC on gas exchange
* Decreased oxygen reserves: because the FRC acts as the main oxygen reservoir, the loss of volume here will give rise to an increased fluctuation in the bloodstream oxygen contentbetween breaths, and during episodes of apnoea.
* Increased atelectasis: Decreasing the FRC to below the closing capacity tends to produce resorption atelectasis, as small airways close in expiration.
* Increased shunt: The consequence of abovementioned atelectasis will be shunt, i.e regions of lung which do not participate in gas exchange because they are not ventilated.

deranged

note; decreased amount of air/aoxygen thus more shunt

Question 22

2017 march Q8
Describe the physiological consequences of decreasing the functional residual capacity (FRC) in an adult by 1 litre.

exact same as 2010 aug

Effect of decreased FRC on gas exchange

Answer 22

Effect of decreased FRC on gas exchange
* Decreased oxygen reserves: because the FRC acts as the main oxygen reservoir, the loss of volume here will give rise to an increased fluctuation in the bloodstream oxygen contentbetween breaths, and during episodes of apnoea.
* Increased atelectasis: Decreasing the FRC to below the closing capacity tends to produce resorption atelectasis, as small airways close in expiration.
* Increased shunt: The consequence of abovementioned atelectasis will be shunt, i.e regions of lung which do not participate in gas exchange because they are not ventilated.

deranged

Question 23

2017 march Q8
Describe the physiological consequences of decreasing the functional residual capacity (FRC) in an adult by 1 litre.

exact same as 2010 aug

Effects of decreased FRC on the pulmonary circulation

Answer 23

Effects of decreased FRC on the pulmonary circulation
* Increased pulmonary vascular resistance, partly due to the effect of narrowed alveoli on perialveolar vessel caliber and partly owing to the inevitable increase in collapsed hypoxic lung regions which promote hypoxic pulmonary vasoconstriction.
* Increased right ventricular afterload, which is due to the increase in pulmonary pressure

deranged

note; this is a great explanation of why when FCR decreases you get decrease pulmonary capillary radius and thus increased pulmonary vascular resistance and the reason is because of hypoix pulmonary asoconstriciton

Question 24

2017 march Q8
Describe the physiological consequences of decreasing the functional residual capacity (FRC) in an adult by 1 litre.

exact same as 2010 aug

examiner comment

Answer 24

2017 march Q8
Describe the physiological consequences of decreasing the functional residual capacity (FRC) in an adult by 1 litre.

High scoring answers began with a definition and normal values, followed by a detailed list of the consequences of decreasing the FRC. Some candidates included descriptions of the normal function of FRC, conditions that decrease FRC and ways of improving reduced FRC. These were not required and did not attract marks. Diagrams require correctly labelled axes, values & units.

2010 aug 15
Describe the physiological consequences of decreasing Functional Residual Capacity (FRC) by one litre in an adult.

This is core knowledge and it was expected candidates would describe physiological
consequences accurately. Good answers included a definition of FRC and correct value. A number of candidates omitted this. It was also expected that candidates mention that as FRC falls, alveolar closure occurs, lung compliance decreases and airway resistance increases work of breathing increases, pulmonary vascular resistance, and thus right ventricular afterload increases. Many candidates described alveolar closure as causing increased dead space ventilation rather than altered V/Q.
Syllabus: B1e
References: Nunn’s respiratory physiology, pages 51-56

note; most important points also expected that candidates mention that as FRC falls, alveolar closure occurs, lung compliance decreases and airway resistance increases work of breathing increases, pulmonary vascular resistance, and thus right ventricular afterload increases.

Question 25

tell me all the volumes

Answer 25

remember volume is always smallest
remember my trick there is 4 building blods and 4 combinations

Tidal volume (TV) Amount of air inhaled during a normal breath 0.5 –
.
Expiratory reserve volume (ERV) Amount of air that can be exhaled after a normal exhalation 1.2 –
.
Inspiratory reserve volume (IRV) Amount of air that can be further inhaled after a normal inhalation 3.1 –
.
Residual volume (RV) Air left in the lungs after a forced exhalation 1.2 –
.
.
Vital capacity (VC) Maximum amount of air that can be moved in or out of the lungs in a single respiratory cycle 4.8 ERV+TV+IRV

.
Inspiratory capacity (IC) Volume of air that can be inhaled in addition to a normal exhalation 3.6 TV+IRV
.
Functional residual capacity (FRC) Volume of air remaining after a normal exhalation 2.4 ERV+RV
.
Total lung capacity (TLC) Total volume of air in the lungs after a maximal inspiration 6.0 RV+ERV+TV+IRV
.
Forced expiratory volume (FEV1) How much air can be forced out of the lungs over a specific time period, usually one second ~4.1 to 5.5 –

Question 26

2020 aug Q13
Describe the anatomical (20% marks) and physiological (80% marks) features of the pulmonary circulation.

Anatomy of the pulmonary circulation:

Answer 26

2020 aug Q13
Describe the anatomical (20% marks) and physiological (80% marks) features of the pulmonary circulation.
deranged

Anatomy of the pulmonary circulation:

• Vessel walls which are much thinner and less muscular than the systemic circuit
  o Pulmonary trunk (~ 30mm diameter) divides into pulmonary arteries
  o Pulmonary arteries can be divided into:
   elastic (large)
   muscular (small)
   nonmuscular (the smallest)
• Pulmonary arteries and veins travel with bronchi, nerves and lymphatics in bronchovascular bundles, which are extensions of the visceral pleura
  o The clinical relevance of these structures is the tendency of oedema fluid to accumulate in them, creating “peribronchial cuffing”
• Pulmonary capillaries start from terminal bronchioles, and form a vascular sheet, interrupted by intercapillary posts.
• Pulmonary veins drain into the left atrium and are continuous with it, up to the point where they contain some cardiac myocytes (which can be sources of atrial fibrillation)

Question 27

2020 aug Q13
Describe the anatomical (20% marks) and physiological (80% marks) features of the pulmonary circulation.

Physiological features of the pulmonary circulation:

• The pulmonary circulation:

Answer 27

2020 aug Q13
Describe the anatomical (20% marks) and physiological (80% marks) features of the pulmonary circulation.
deranged

• The pulmonary circulation:
  o A low pressure, highly elastic system
  o Contains ~10% of the circulating blood volume, or about 500ml.

Question 28

2020 aug Q13
Describe the anatomical (20% marks) and physiological (80% marks) features of the pulmonary circulation.

Physiological features of the pulmonary circulation:

Pulmonary blood flow:

Answer 28

2020 aug Q13
Describe the anatomical (20% marks) and physiological (80% marks) features of the pulmonary circulation.
deranged

Pulmonary blood flow:
Pulmonary arterial flow is equal to the cardiac output and consists of mixed venous blood
Pulmonary venous flow: oxygenated pulmonary capillary blood + physiological shunt

Question 29

2020 aug Q13
Describe the anatomical (20% marks) and physiological (80% marks) features of the pulmonary circulation.

Physiological features of the pulmonary circulation:

Pressures in the pulmonary circulation

Answer 29

2020 aug Q13
Describe the anatomical (20% marks) and physiological (80% marks) features of the pulmonary circulation.
deranged

Pressures in the pulmonary circulation
PA systolic pressure = 18-25 mmHg
PA diastolic pressure = 8-15 mmHg
Mean pulmonary arterial pressure = 9-16 mmHg
Pulmonary capillary pressure = 8-10mmHg
Pulmonary venous pressure = 6-12 mm Hg

Question 30

2020 aug Q13
Describe the anatomical (20% marks) and physiological (80% marks) features of the pulmonary circulation.

Physiological features of the pulmonary circulation:

Pulmonary vascular resistance:

Answer 30

2020 aug Q13
Describe the anatomical (20% marks) and physiological (80% marks) features of the pulmonary circulation.
deranged

Pulmonary vascular resistance:
Approximately 1/10th of the systemic (SVR).
PVR is 100-200 dynes/sec/cm-5, or 255 - 285 dynes-sec/cm–5/m2 for PRVI

Question 31

2020 aug Q13
Describe the anatomical (20% marks) and physiological (80% marks) features of the pulmonary circulation.

Physiological features of the pulmonary circulation:

Regulation

Answer 31

2020 aug Q13
Describe the anatomical (20% marks) and physiological (80% marks) features of the pulmonary circulation.
deranged

Regulation
Autonomic (sympathetic nervous system)
Intrinsic (eg. hypoxic pulmonary vasoconstriction)
Humoral (eg. circulating catecholamines)

Question 32

2020 aug Q13
Describe the anatomical (20% marks) and physiological (80% marks) features of the pulmonary circulation.

Physiological features of the pulmonary circulation:

Regional distribution

Answer 32

2020 aug Q13
Describe the anatomical (20% marks) and physiological (80% marks) features of the pulmonary circulation.
deranged

Regional distribution
Hydrostatic and alveolar pressure (West’s Zones describe the distribution of blood flow according to hydrostatic pressure due to gravity and alveolar pressure)
Regional distribution of oxygenation
hypoxic pulmonary vasoconstriction redirects blood flow away from poorly ventilated regions
Dependent on lung volume (relationship between lung volume and PVR is “U”-shaped)

Question 33

2020 aug Q13
Describe the anatomical (20% marks) and physiological (80% marks) features of the pulmonary circulation.

Physiological features of the pulmonary circulation:

Function

Answer 33

2020 aug Q13
Describe the anatomical (20% marks) and physiological (80% marks) features of the pulmonary circulation.
deranged

Function
​​​​​​​Gas exchange
Reservoir of blood (10% of circulating volume)
Filter (particles larger than an RBC are trapped; ~8 μm size barrier)
Modulation of body temperature (heat exchange with alveolar gas)

Question 34

2020 aug Q13
Describe the anatomical (20% marks) and physiological (80% marks) features of the pulmonary circulation.

Physiological features of the pulmonary circulation:

examiner comment

Answer 34

2020 aug Q13
Describe the anatomical (20% marks) and physiological (80% marks) features of the pulmonary circulation.
deranged

The examiners consider that an understanding of the pulmonary circulation is core area of the syllabus. In general, the anatomy section was better answered than the physiological features. As well as a description of the gross anatomy of the pulmonary circulation tracking it from the pulmonary valve to the left atrium, some mention of the microscopic anatomy was required (e.g., that the pulmonary arteries are thin walled with little smooth muscle).

For the second part of the question, a breadth of knowledge was required. Candidates were expected to address the following physiological features of the pulmonary circulation: volume, pressure, resistance, regulation and regional distribution and function. Marks were apportioned to each section, so it was important to write something on each section. Focussing on one section in detail (e.g., a very detailed description of West’s Zones) usually came at the expense of missing one or more of the other sections, most commonly the functions of the pulmonary circulation. Indeed, candidates that scored well provided information on each section and for the functions of the pulmonary circulation mentioned more than gas exchange.

Question 35

Describe the anatomy of the larynx

repeat 2020 august, 2018 august, 2017 march, and 2015 march,, 2012 march, JC made slight alterations to 2020 to make it better

others
Describe the surface anatomy of the anterior neck (30% of marks) and the underlying structures relevant to performing a tracheostomy (70% of marks

Describe the anatomy of the neck and trachea relevant to the insertion of a tracheostomy

Outline the anatomy relevant to performing a percutaneous tracheostomy

question
* Landmarks:

Answer 35

• Landmarks:
  o Laryngeal prominence (“Adam’s apple”)

Laryngeal prominence (“Adam’s apple”)

deranged
2020 august 14
Describe the anatomy of the larynx

Question 36

Describe the anatomy of the larynx

repeat 2020 august, 2018 august, 2017 march, and 2015 march,, 2012 march, JC made slight alterations to 2020 to make it better

others
Describe the surface anatomy of the anterior neck (30% of marks) and the underlying structures relevant to performing a tracheostomy (70% of marks

Describe the anatomy of the neck and trachea relevant to the insertion of a tracheostomy

Outline the anatomy relevant to performing a percutaneous tracheostomy

question
* Basic structural anatomy:

Answer 36

• Basic structural anatomy:
  o Considered part of the respiratory tract
  o Lined by pseudostratified columnar ciliated epithelium
  o Divides the airways into “upper” and “lower”

deranged
2020 august 14
Describe the anatomy of the larynx

Question 37

Describe the anatomy of the larynx

repeat 2020 august, 2018 august, 2017 march, and 2015 march,, 2012 march, JC made slight alterations to 2020 to make it better

others
Describe the surface anatomy of the anterior neck (30% of marks) and the underlying structures relevant to performing a tracheostomy (70% of marks

Describe the anatomy of the neck and trachea relevant to the insertion of a tracheostomy

Outline the anatomy relevant to performing a percutaneous tracheostomy

question
* Relations:

Answer 37

• Relations:
  o Superiorly: bounded by the hyoid bone
  o Anteriorly, covered by skin and protected by the thyroid cartilage
  o Inferiorly: becomes continuous with the trachea at the level of C6
  o Posteriorly: projects into the laryngopharynx
  o Divided by the vocal folds into upper and lower half

o Laryngeal inlet:
 Faces backwards and upwards
 Bounded anteriorly by the upper edge of the epiglottis,
 Bounded laterally and postriorly by the aryepiglottic folds
 Bounded posteriorly by the interarytenoid fissure

deranged
2020 august 14
Describe the anatomy of the larynx

Question 38

Describe the anatomy of the larynx

repeat 2020 august, 2018 august, 2017 march, and 2015 march,, 2012 march, JC made slight alterations to 2020 to make it better

others
Describe the surface anatomy of the anterior neck (30% of marks) and the underlying structures relevant to performing a tracheostomy (70% of marks

Describe the anatomy of the neck and trachea relevant to the insertion of a tracheostomy

Outline the anatomy relevant to performing a percutaneous tracheostomy

question
o Laryngeal inlet:

Answer 38

o Laryngeal inlet:
 Faces backwards and upwards
 Bounded anteriorly by the upper edge of the epiglottis,
 Bounded laterally and postriorly by the aryepiglottic folds
 Bounded posteriorly by the interarytenoid fissure

deranged
2020 august 14
Describe the anatomy of the larynx

Question 39

Describe the anatomy of the larynx

repeat 2020 august, 2018 august, 2017 march, and 2015 march,, 2012 march, JC made slight alterations to 2020 to make it better

others
Describe the surface anatomy of the anterior neck (30% of marks) and the underlying structures relevant to performing a tracheostomy (70% of marks

Describe the anatomy of the neck and trachea relevant to the insertion of a tracheostomy

Outline the anatomy relevant to performing a percutaneous tracheostomy

question
* Blood supply:

Answer 39

• Blood supply:
  o Upper half: superior laryngeal branch of the superior thyroid artery
  o Lower half: inferior laryngeal branch of the inferior thyroid artery

deranged
2020 august 14
Describe the anatomy of the larynx

Question 40

Describe the anatomy of the larynx

repeat 2020 august, 2018 august, 2017 march, and 2015 march,, 2012 march, JC made slight alterations to 2020 to make it better

others
Describe the surface anatomy of the anterior neck (30% of marks) and the underlying structures relevant to performing a tracheostomy (70% of marks

Describe the anatomy of the neck and trachea relevant to the insertion of a tracheostomy

Outline the anatomy relevant to performing a percutaneous tracheostomy

question
* Venous drainage:

Answer 40

• Venous drainage:
  o Upper half: superior laryngeal veins which empty into the superior thyroid veins
  o Lower half:inferior laryngeal veins to the inferior thyroid veins, which drain into the brachiocephalic veins

deranged
2020 august 14
Describe the anatomy of the larynx

Question 41

Describe the anatomy of the larynx

repeat 2020 august, 2018 august, 2017 march, and 2015 march,, 2012 march, JC made slight alterations to 2020 to make it better

others
Describe the surface anatomy of the anterior neck (30% of marks) and the underlying structures relevant to performing a tracheostomy (70% of marks

Describe the anatomy of the neck and trachea relevant to the insertion of a tracheostomy

Outline the anatomy relevant to performing a percutaneous tracheostomy

question
* Lymphatic drainage:

Answer 41

• Lymphatic drainage:
  o upper and lower groups of deep cervical nodes

deranged
2020 august 14
Describe the anatomy of the larynx

Question 42

Describe the anatomy of the larynx

repeat 2020 august, 2018 august, 2017 march, and 2015 march,, 2012 march, JC made slight alterations to 2020 to make it better

others
Describe the surface anatomy of the anterior neck (30% of marks) and the underlying structures relevant to performing a tracheostomy (70% of marks

Describe the anatomy of the neck and trachea relevant to the insertion of a tracheostomy

Outline the anatomy relevant to performing a percutaneous tracheostomy

question
* Ligaments:

Answer 42

• Ligaments:
  o Intrinsic: cricothyroid ligament and quadrangular membrane
  o Extrinsic: thyrohyoid membrane, median and lateral thyrohyoid ligament, hyo-epiglottic ligament, cricotracheal ligament.

deranged
2020 august 14
Describe the anatomy of the larynx

Question 43

Describe the anatomy of the larynx

repeat 2020 august, 2018 august, 2017 march, and 2015 march,, 2012 march, JC made slight alterations to 2020 to make it better

others
Describe the surface anatomy of the anterior neck (30% of marks) and the underlying structures relevant to performing a tracheostomy (70% of marks

Describe the anatomy of the neck and trachea relevant to the insertion of a tracheostomy

Outline the anatomy relevant to performing a percutaneous tracheostomy

question
* Muscles:

Answer 43

• Muscles:
  o Intrinsic: cricothyroid, thyroarytenoid, posterior cricoarytenoid, lateral cricoarytenoid, transverse and oblique arytenoids.
  o Extrinsic: supra and infrahyoid group of muscles: digastric, mylohyoid, stylohyoid, omohyoid, thyrohyoid. Also sternohyoid and sternothyroid.

deranged
2020 august 14
Describe the anatomy of the larynx

Question 44

Describe the anatomy of the larynx

repeat 2020 august, 2018 august, 2017 march, and 2015 march,, 2012 march, JC made slight alterations to 2020 to make it better

others
Describe the surface anatomy of the anterior neck (30% of marks) and the underlying structures relevant to performing a tracheostomy (70% of marks

Describe the anatomy of the neck and trachea relevant to the insertion of a tracheostomy

Outline the anatomy relevant to performing a percutaneous tracheostomy

question
* Innervation:

Answer 44

• Innervation:
  o All the muscles of the larynx are supplied by the recurrent laryngeal nerve except cricothyroid which is innervated on its external surface by the external laryngeal nerve.

deranged
2020 august 14
Describe the anatomy of the larynx

Question 45

Describe the anatomy of the larynx

repeat 2020 august, 2018 august, 2017 march, and 2015 march,, 2012 march, JC made slight alterations to 2020 to make it better

others
Describe the surface anatomy of the anterior neck (30% of marks) and the underlying structures relevant to performing a tracheostomy (70% of marks

Describe the anatomy of the neck and trachea relevant to the insertion of a tracheostomy

Outline the anatomy relevant to performing a percutaneous tracheostomy

question
* Function

Answer 45

• Function
  o Respiration (conductive airway)
  o Swallowing
  o Phonation
  o Cough reflex

deranged
2020 august 14
Describe the anatomy of the larynx

Question 46

Describe the anatomy of the larynx

repeat 2020 august, 2018 august, 2017 march, and 2015 march,, 2012 march, JC made slight alterations to 2020 to make it better

others
Describe the surface anatomy of the anterior neck (30% of marks) and the underlying structures relevant to performing a tracheostomy (70% of marks

Describe the anatomy of the neck and trachea relevant to the insertion of a tracheostomy

Outline the anatomy relevant to performing a percutaneous tracheostomy

examiner comments

Answer 46

2020 august 14
Describe the anatomy of the larynx

For this question, candidates were expected to address the location of the larynx, its relations, the cartilages (single and paired), ligaments, muscles (intrinsic and extrinsic), innervation (sensory and muscular) and blood supply (including venous drainage). Marks were apportioned to each section, so whilst some detail was required, breadth of knowledge was also important. Most candidates had a grasp of the gross anatomy, the main relations and at least the innervation provided by the recurrent laryngeal nerve. However, an understanding of the functional anatomy of the cartilages was not always apparent. It should be noted that not every single muscle needed to be named (especially for the extrinsic muscles), but an understanding of the major muscle groups should have been included.

2018 august Q1
Answers required a description of the surface anatomy outlining the midline structures including the hyoid bone and cartilages. The tissue layers should have been mentioned as should the relevant tracheal anatomy. The anterior, posterior and lateral relations of the trachea should also have been included along with the relevant nerves and blood vessels. Diagrams were not essential but could have been included.
Candidates should note that marks were not awarded for a description of how to perform a tracheostomy

2017 march 11
Describe the anatomy of the neck and trachea relevant to the insertion of a tracheostomy

Many candidates described how to perform a tracheostomy or the structure of the trachea rather than the relevant anatomical relations. It was expected that answers include anterior, posterior and lateral relations at the correct tracheal level including relevant vascular structures.

2015 marchQ24
Outline the anatomy of the larynx

It was expected that an answer would include the names of the three single and three paired laryngeal cartilages, intrinsic and extrinsic muscles (names were not required), nerve supply (motor and sensory) and blood supply. Many candidates had good illustrations though a
drawing was not essential. The majority of candidates failed to name the laryngeal cartilages. There was much confusion about whether certain structures were bones or cartilage or even muscle. The relation of the larynx to the thyroid gland was frequently misunderstood
Many answers focussed on the relations of the larynx but omitted basic information about the larynx itself. No marks were awarded for the contents of the carotid sheath or the course of the recurrent laryngeal nerve both of which were frequently included in answers.

2012 march Q10
10 Describe the anatomy of the neck and trachea relevant to the insertion of a tracheostomy
For a good answer candidates were expected to mention surface anatomy of the anterior of the neck from the superior to inferior aspects (e.g. hyoid bone, thyroid cartilage, cricothyroid ligament, cricoid cartilage and thyroid gland with sternohyoid muscle just lateral to the midline structures, the pathway of the trachea from anterior at level of larynx to more posterior as it enters the chest behind the sternal notch, nature of the tracheal rings (C shaped cartilages (first cartilage is bigger than the others in the cervical trachea) joined vertically by fibro-elastic tissue and connected posteriorly by the trachealis muscle, layers of dissection for tracheostomy (e.g. skin, subcutaneous tissue, fat, pre-tracheal fascia (superficial and deep), trachea and the relationship of thyroid to the trachea and surrounding vessels. There were some good answers amongst the successful candidates, whereas those who failed to pass this question did so because of a lack of detailed knowledge and relational anatomy. Candidates were not asked, and thus did not receive marks for, describing how to perform a tracheostomy.

2009 feb 8
Outline the anatomy relevant to performing a percutaneous tracheostomy.
Surface landmarks, anatomy of the trachea and its important relationships with the thyroid,
carotid sheath and oesophagus were required to pass this question. Several candidates
described the procedure of percutaneous tracheostomy in great detail. Descriptions of the
procedure gained no marks.
Syllabus B1b2g
Reference: Anatomy for the Anaesthetist, Ellis and Feldman.