Which of the following statements about alveolar pressure (Palv) ...

[go.lag]

Which of the following statements about alveolar pressure (Palv) during normal quiet breathing is true?
 
  a. It is positive during inspiration and nega-tive during expiration.
  b. It is the same as intrapleural pressure (Ppl).
  c. It is negative during inspiration and posi-tive during expiration.
  d. It always remains less than atmospheric pressure.

Question 2

Which of the following pressure gradients is responsible for maintaining alveolar inflation?
 
  a. Transpulmonary pressure gradient (Palv  Ppl)
  b. Transthoracic pressure gradient (Ppl  Pbs)
  c. Transcardiac pressure gradient (Pca  Palv)
  d. Transrespiratory pressure gradient (Palv  Pao)

[coyin]

Answer to Question 1

ANS: C
During inspiration the pleural pressure drops, the transpulmonary pressure gradient widens, caus-ing the alveoli pressure to become sub-atmospheric and gas to enter the lung. During expiration the passive recoil of the lungs cause a supra-atmospheric pressure in the alveoli that causes gas to exit the lung.

Answer to Question 2

ANS: A
Transpulmonary or PL is the pressure difference that maintains alveolar inflation.

[go.lag]

TYSM

[Animal_Goddess]

Gracias!