During inspiration, muscular contraction of the diaphragm causes ...

[a0266361136]

During inspiration, muscular contraction of the diaphragm causes air to move into the lung. The mechanism that drives air movement during inspiration results in a(n):
 
  a. decrease in intra-alveolar pressure and shortening of the rib cage.
  b. decrease in the size of the thorax and alveolar expansion.
  c. increase in the size of the thorax and decrease in intrapleural pressure.
  d. increase in atmospheric pressure and intrapleural pressure.

Question 2

If an individual with respiratory difficulty were retaining too much carbon dioxide, which of the following compensatory responses would the nurse expect to be initiated?
 
  a. Increase in respiratory rate
  b. Decrease in ventilation rate
  c. Increase in tidal volume
  d. Vasodilation of the pulmonary arterioles

[Jordin Calloway]

Answer to Question 1

ANS: C
Inspiration occurs due to an increase in the size of the thorax and a decrease in intrapleural pres-sure, thus creating a negative pressure that draws air into the lungs. The rib cage lengthens, not shortens. The size of the thorax increases, not decreases. Intrapleural pressure decreases, not in-creases.

Answer to Question 2

ANS: A
To rid the body of excess carbon dioxide, the rate and depth of respiration are increased. A de-crease in ventilation rate would increase carbon dioxide. An increase in tidal volume would not decrease carbon dioxide. Vasodilation of the pulmonary arterioles will not rid the body of carbon dioxide.