백서 근섬유와 그 지배신경 유수섬유와의 량적관계에 대한 관찰

초록

For clarifing the relationships between the number of muscle fibers and rhlated nerve fibes. the superior oblique muscle of eye and the soleus muscle from 3-week old young and 7-month old adult albino rats were investigated by counting total number of the fibers, and measuring the sizes on cross-sections of both the muscle and nerve fibers. 1. The mean numbers of superior oblique muscle fibers were 1,522 in 3-week old rats and 1,660 in adult rats; of soleus muscle, 2,208 in 3-week old and 2,264 in adult. Thus, the number of the muscle fibers was not significantly different between younger and older groups. 2. Of superior oblique muscle, the mean diameters of the central fibers and peripheral fibers in the 3-week old rats were 8.5 microns and 7.3 microns respectively, which were 15.0 microns and 11.9 microns in the adult rats showing 1.8 times and 1.6 times Increase in size respectively. Of soleus muscle, the mean diameter of the 3-week old rats was 13.0 microns, whereas, that of adult 32.3 microns that is, approximately 2.5 times increase in size. 3. Myelinated fibers of trochlear nerve in young rats were 252 and in adult 283 in number; those of soleus branch of the nerve fibers were 129 and 132 in number respectively. 4. The ratio of nerve fibers to muscle fibers in number were 1 : 6 in the ocular muscle and 1 : 17 in the soleus muscle.