An additional mechanismavailable to internally and externally
pipped embryos to influence V ·
O2lung is the alteration of lung
ventilation patterns. Externally pipped embryos increased tidal
volume (VT) with a relatively constant ventilation frequency ( f )
in response to ventilating their lungs with hypoxic and
hypercapnic gas (Menna and Mortola, 2003). It is possible that
the internally pipped embryo may have the ability to alterV ·
O2lung
by changing ventilation patterns much like the externally pipped
embryo to help compensate for changes in air cell O2 content.