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Question 1

Where in the respiratory tract is the greatest resistance to airflow?

Answer 1

In the trachea and large bronchi (dropping away after ~7 branching generations)

(For any tube: resistance is inversely proportional to the 4th power of the radius)

Question 2

What do type I pneumocytes do?

Answer 2

Gas exchange

~95% of the surface area of the alveolar surface of the lung is type I pneumocytes

Question 3

What do type II pneumocytes do?

Answer 3

• Repair alveolar epithelium
• produce secrete pulmonary surfactant

~5% of the alveolar surface area of the lungs is type II pneumocytes

Question 4

Where are central receptors and what do they do?

Answer 4

Located in the medulla oblongata and detect changes in the pH of spinal fluid.

CO2 is converted into carbonic acid in the bloodstream so changes the concentration of H+ ions (and thus pH)

Question 5

Where are peripheral chemoreceptors and what do they do?

Answer 5

Found in the aortic body and detect changes in the blood oxygen and CO2 levels (but not pH).
Found in the carotid body which detects all 3

Question 6

What is type 1 respiratory failure?

Answer 6

Low levels of O2 in the blood (hypoxemia) without an increased level of CO2 in the blood (hypercapnia)

Question 7

What is type 2 respiratory failure?

Answer 7

Low level of O2 in the blood (hypoxemia) with high levels of CO2 in the blood (hypercapnia)