Robbins 9th ed - Chapter 15 - Lungs (2)

Question 1

What type of epithelium lines the entire respiratory tract (except for the vocal cords)?

Answer 1

Pseudostratified, tall, columnar, ciliated epithelium. “Pseudostratified” means that in truth there is only a single layer of epithelial cells, but the variable location of the nucleus makes it look like it’s stratified. This type of epithelium lines the trachea, bronchi, and respiratory zone.

Question 2

What is a Type I pneumocyte?

Answer 2

This is the flattened cell type that makes up 95% of the alveolar surface.

Question 3

What is a Type II pneumocyte?

Answer 3

This is the rounded cell type that makes up 5% of the alveolar surface. Type II pneumocytes synthesize surfactant.
They also give rise to Type I pneumocytes in order to repair damaged alveolar epithelium.

Question 4

What are the Pores of Kohn?

Answer 4

These are the pores between alveoli. Bacteria and fluid can pass through these pores.

Question 5

What is compressive atelectasis?

Answer 5

This is when the airways are forced to collapse by any significant volume of fluid (e.g. ascites), air (e.g. pneumothorax) or tumour. The mediastinum moves AWAY from the lesion.

Question 6

What is resorptive atelectasis?

Answer 6

This occurs as a result of complete airway obstruction (e.g. from mucous plugging, inhaled foreign body), and over time the airways distal to the obstruction collapse due to resorption of the air within them. The mediastinum moves TOWARDS the lesion.

Question 7

What is contraction atelectasis?

Answer 7

This occurs when there is prevention of full lung expansion (e.g. neonatal atelectasis, chronic fibrosis)

Question 8

What proportion of pulmonary emboli result in infarction? What type of patient population does PE result in infarction?

Answer 8

10% (usually in patients with cardiac failure, and thus compromised pulmonary circulation)