Gas Exchange: Topic 6.4

Question 1

Outline the function of type I and type II pneumocytes.

Answer 1

Type I: flattened (squamous) and extremely thin to decrease diffusion distance and increase surface area for gas exchange
Type II: cuboidal, purpose is to make the surfactant that reduces surface tension ensuring all alveoli expand at the same rate and none collapse

Question 2

Calculate ventilation rate using a graph of spirometer data.

Answer 2

Breaths per minute

Question 3

Outline the processes of inspiration and exhalation (including the roles of antagonistic muscles)

Answer 3

Inspiration: Diaphragm muscles contract and external intercostal muscles contract pulling ribs up and out, thoracic cavity volume and lung volume increase while pressure in the lungs decreases causing air to rush in
Exhalation: Diaphragm muscles relax, abdominal wall muscles contract, external intercostal muscles relax letting the ribs fall and internal intercostal muscles contract pulling the ribs down causing thoracic cavity and lung volume to decrease while pressure increases causing air to rush out