Rehaan Case 6 SBA Circuits

A 28-year-old pregnant woman is admitted to the hospital and gives birth to a baby boy at 31 weeks gestation. The baby appears visibly distressed with tachypnoea, tachycardia, expiratory grunting, nasal flaring, and chest wall recession.​

Which type of cell normally produces the substance that this baby is deficient in?​

• Type 1 alveolar cells​

• Type 2 alveolar cells

• Neuroendocrine cells​

• Goblet cells​

• Ciliated cells​

Select the statement that most correctly describes the pathway of oxygen from the alveoli to the blood.​

• Across alveolar epithelium, along capillary endothelium​

• Across alveolar endothelium, along capillary epithelium​

• Across alveolar cell wall, along capillary endothelium​

• Across alveolar cell membrane, along capillary cell membrane

• Across alveolar elastic walls, along capillary endothelium​

Select the main driver of ventilation in a healthy adult.​

• High arterial [H+] concentration

• High PaCO2​

• Low PaCO2​

• Low PaO2

• Low arterial [H+] concentration

Select the statement that best describes the effects of the parasympathetic nerves on the respiratory tract​

• Bronchoconstriction, increased mucus secretion

• Bronchodilation, decreased mucus secretion​

• Bronchoconstriction, decreased mucus secretion​

• Bronchodilation, increased mucus secretion​

• Bronchodilation, no change to mucus secretion​

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The anatomical landmark to decompress a tension pneumothorax with a chest drain is the 5th intercostal space, mid-axillary line. Select the label which correctly identifies this landmark. ​

• A

• B

• C

• D

• E

A healthy 6 year old takes a very deep breath in while preparing to blow her birthday candles out. Her lungs are momentarily hyperinflated. ​

Select the statement which correctly describes the behaviour of her lungs in this state.

• Interpleural pressure is relatively close to 0​

• Decreasing the interpleural pressure will cause deflation of the lungs​

• The lung tissue is nearing its elastic limit​

• The lung tissue has a relatively high compliance compared to a normal level of inflation​

• Interpleural pressure may reach +2kPa​

Select the best statement describing why patients with alveolar fibrosis have reduced lung compliance.​

• Change in lung volume is more than lung pressure meaning there is an increased difference in (overall) pressure.​

• Change in lung pressure is less than lung volume meaning there is a decreased difference in (overall) pressure.​

• Change in lung pressure is more than change lung volume meaning there is an increased in the difference in (overall) pressure.​

• Change in lung volume is less than change in lung pressure meaning there is an increased difference in (overall) pressure.​

Which statement correctly describes the difference between obstructive and restrictive lung diseases?​

• In obstructive lung disease, FEV1: FVC ratio is normal as FVC increases more than FEV1 whereas in restrictive lung disease, FEV1: FVC ratio is normal as both FEV1 and FVC are increased.​

• In obstructive lung disease, FEV1: FVC ratio is reduced as FEV1 increases more than FVC whereas in restrictive lung disease, FEV1: FVC ratio is reduced as FEV1 increases more than FVC.​

• In obstructive lung disease, FEV1: FVC ratio is normal as FEV1 decreases more than FVC whereas in restrictive lung disease, FEV1: FVC ratio is normal as both FEV1 and FVC are reduced. ​

• In obstructive lung disease, FEV1: FVC ratio is reduced as FVC decreases more than FEV1 whereas in restrictive lung disease, FEV1: FVC ratio is normal FEV1 reduces more than FVC.​

Which statement correctly describes the changes to the values of PAO2 and PACO2 when there is V/Q mismatch in the lungs?​

• When V > Q, PAO2 falls and PACO2 rises​

• When Q > V, PAO2 rises and PACO2 falls​

• When Q > V, PAO2 falls and PACO2 rises​

• When V > Q, PAO2 rises and PACO2 rises​

Select the statement that correctly describes the mechanisms to regulate V/Q between individual alveoli.​

• Hypercapnic pulmonary vasoconstriction restores optimal V/Q when there is relative overperfusion​

• The Hering-Breuer reflex reduces respiratory rate to prevent overventilation which would give too high a V/Q ​

• Hypoxia-induced bronchoconstriction restores optimal V/Q when there is relative overventilation​

• The pontine respiratory group induces phase-switching to expiration to prevent overventilation which would give too high a V/Q​

• The last in-first out principle increases oxygen delivery to relatively more obstructed alveoli​