AJP - Regulatory, Integrative and Comparative Physiology, Vol 249, Issue 4 477-R481, Copyright © 1985 by American Physiological Society
Distribution of ventilation in American alligator Alligator mississippiensis
P. E. Bickler, R. G. Spragg, M. T. Hartman and F. N. White
The regional distribution of ventilation in the multicameral lung of
spontaneously ventilating alligators (Alligator mississippiensis) was
studied with 133Xe scintigraphy. Frequent gamma camera images of 133Xe
washin and washout were obtained and processed to allow evaluation of
regional ventilation. Washin of 133Xe to equilibrium occurred in three to
four breaths in anterior, central, and posterior compartments. Washin was
most rapid in the posterior compartment and slowest in the anterior. The
structure of the lungs and distribution of ventilation of inspired gas is
consistent with the rapid radial spread of gas through a parallel
arrangement of lung units surrounding the central intrapulmonary bronchus.
Washout to equilibrium of 133Xe from all compartments occurred within three
to four breaths. This rapid washin and washout of gas to all parts of the
lung stands in contrast to the lungs of turtles and snakes, in which the
caudal air sacs are relatively poorly ventilated.
