myofibrilla has definitions from the field of biology
1
[ noun ] (biology) one of many contractile filaments that make up a striated muscle fiber

Used in print

(J. W. C. Hagstrom et al., "Debilitating muscular...)

In contrast to the nuclear changes described above , another change in muscle nuclei was seen , usually occurring in fibers that were somewhat smaller than normal but that showed distinct cross striations and myofibrillae .

Occasionally there were small basophilic fibers that were devoid_of myofibrillae and contained many vesicular nuclei with prominent nucleoli ( Fig. 5 ) .

*