Nonlinear Control of Breathing Activity in Early Development
Spontaneous breathing movements have been described in the fetal sheep, fetal baboon and the human fetus prior to birth. In the fetal lamb and baboon, breathing movements can be observed as electromyographic activity in the diaphragm coupled with negative changes in intratracheal pressure,. Movements of the fetal chest wall and diaphragm can readily be seen with the use of real-time ultrasound in the human. Although they do not regulate fetal oxygenation, fetal breathing movements are similar to postnatal respiratory activity in that they involve phrenic nerve firing and are modulated by a variety of chemical signals including hypoxia, hypercarbia and pharmacological agents such as opiates. However, the dynamics of fetal breathing movements are quite unique and very different from the postnatal breathing pattern.
KeywordsBreathing Pattern Human Fetus Breathing Rate Breathing Movement Fetal Sheep
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