Postnatal development of masticatory and digestive organs and their regulation factors

Postnatal development of masticatory and digestive organs and their regulation factors were reviewed.In the morphogenesis of the skull, the differentiation of the chondrocranium is almost exclusively governed by intrinsic genetic factors, but the desmocranial growth, particularly in the upper and lower jaws, is influenced by many epigenetic factors originating from adjacent head structures and by local environmental factors occurring in form of pressure and tension forces from the masticatory muscles and other soft tissues. Each of the soft tissues associated with various functions in the skull was termed the “functional matrix” by Moss (1968). Growth and maintenance of the skull unit may depend exclusively upon its related functional matrix.Moreover, in a series of experiments using rats and mice, it was shown that hormones and diets affected the postnatal development of the skull. Also, in the masticatory muscle and parotid gland, these factors influenced their development, and the same controlled the postnatal development of other digestive organs like the stomach and pancreas. Thus, in the masticatory and digestive organs, many factors are involved in their development, and some of these organs are controlled by the same factors.Moreover, recently, many regulatory factors for bone formation have been found in vivo and in vitro.Therefore, further studies are needed for analysis of the control factors involved in the postnatal developmnt of masticatory and digestive organs, their regulation systems and interelationships between them.