CRL Quiz 1 2007

1

Which one of the following statements regarding the structure of the lungs is correct?


  The terminal bronchioles are the smallest airways without alveoli.

  The respiratory bronchioles make up part of the anatomic dead space.

  The bronchioles have cartilage in their walls.

  The alveolar-capillary membrane has a surface area of 10m2 and a thickness of 0.5mm.

2

Which one of the following statements regarding inspiration is correct?


  At rest inspiration is an active process accounting for 20% of the total oxygen consumption.

  Work is required to inflate the lungs from residual volume (RV) to functional residual capacity.

  During inspiration pleural pressure is more negative at the lung bases than the apices in an erect individual.

  Vital capacity (VC) is the difference between total lung capacity (TLC) and RV.

3

Which one of the following statements regarding spirometry is correct?


  Spirometry measures the time course of the expiratory flow from TLC to RV.

  A restrictive ventilatory defect is not the only cause of a reduced VC.

  In a normal young adult the FEV1/VC is usually less than 80%.

  Airflow obstruction usually causes a fall in FEV1 and VC.

4

Which one of the following statements concerning gas exchange across the alveolar-capillary membrane (A-C) is NOT correct?


  Under normal conditions, diffusion does not limit gas exchange.

  Hypoxaemia due to low V/Q units improves with supplemental oxygen.

  Carbon dioxide diffuses more readily than oxygen because it is more soluble.

  Nitrogen is in the alveoli but does not cross the A-C membrane.

5

Which one of the following statements concerning the pulmonary circulation is NOT correct?


  It receives the same cardiac output as the systemic circulation.

  Pressure remains relatively low with increased cardiac output.

  Regional blood flow is controlled by contraction of the pulmonary venules.

  There is a net flow of fluid from the pulmonary capillaries into the interstitial spaces.

  The pressure difference between pulmonary arterioles and pulmonary venules is low.

6

Which one of the following statements about short acting β2-adrenoceptor agonists, for example salbutamol, is NOT correct?


  They have substantial anti-inflammatory effects.

  They are used "only as required" to treat or prevent bronchospasm.

  They act through regulation of cytoplasmic calcium levels.

  They are used to relieve acute asthma attacks.

  They show more tolerance on inflammatory cells than smooth muscle.

7

Which one of the following statements regarding respiratory function is NOT correct?


  Ventilation is greatest in the dependent part of the lungs.

  At functional residual capacity (FRC), outward chest recoil is balanced by inward lung elastic recoil.

  Airway closure at low lung volumes is a determinant of residual volume (RV).

  Closing volume is normally higher than FRC.

  Chest wall stiffness is a determinant of both residual volume (RV) and total lung capacity (TLC).

8

Which one of the following statements regarding the blood vessels is NOT correct?


  The blood flow velocity is slowest in the capillaries.

  Small arteries are important determinants of total peripheral resistance.

  Blood in the pulmonary artery is oxygenated.

  The large arteries act as diastolic pumps.

9

Which one of the following statements regarding blood pressure is NOT correct?


  Pulse pressure will be higher if the large arteries are more compliant.

  Mean arterial pressure is determined by total peripheral resistance.

  Mean arterial pressure is determined by cardiac output.

  Pulse pressure is the difference between systolic blood pressure and diastolic blood pressure.

10

Which one of the following statements about a typical intercostal nerve is NOT correct?


  It is accompanied by an arterial branch of the aorta.

  It is accompanied by a tributary to the azygos system of veins.

  It is located in the upper part of an intercostal space.

  It is located above the accompanying vessels in the intercostal space.

11

In a normal plain chest radiograph (plane CXR) taken to obtain a P-A view:


  The anterior parts of ribs are more magnified than posterior parts.

  The heart occupies about half the diameter of the thoracic cage.

  The right border of the heart shadow includes the right ventricle.

  The film should be taken in full expiration.

12

Which one of the following statements regarding pleura is NOT correct?


  The two pleural cavities do not connect.

  The costodiaphragmatic recess is occupied by lung tissue throughout expiration.

  Parietal pleura is supplied by intercostal nerves.

  Parietal pleura is supplied by phrenic nerve.

13

Which one of the following is NOT a function of the upper airway?


  Cough.

  Swallowing.

  Defence of the lower respiratory system.

  Control of airflow in respiration.

  Gas exchange.

14

Regarding the function of the respiratory system, which one of the following statements is correct?


  The respiratory system regulates body pH by excreting bicarbonate.

  Reduced PaO2 does not necessarily result in reduced tissue oxygen delivery.

  The functional reserve of the lungs is small and humans become incapacitated by minor reductions in lung capacity or modest increases in demand.

  The respiratory system is poorly protected to withstand injury by inhaled and circulating triggers of inflammation.

  Breathlessness is a sensitive and specific symptom of dysfunction of the respiratory system.

15

Which one of the following statements regarding the pulmonary circulation is correct?


  There is a small nett flow of fluid from the pulmonary capillary bed.

  The pulmonary vessels are thin walled because they receive only a proportion of the cardiac output from the right ventricle.

  Spasm of the capillaries diverts blood away from poorly ventilated areas.

  Giving supplemental oxygen improves the reduced PaO2 due to low V/Q units but it does not relieve the arteriolar spasm associated with these units.

  Mean pulmonary artery pressure is about 50% of mean systemic arterial pressure.