Five A-10 myoblast cells tightly adhere to one another before one breaks away as it prepares to undergo mitosis. The division process of the cell occurs out of the field view, but soon after the daughter cells can be seen in the upper right-hand corner, where they both form connections with the original group of cells. This process is repeated several times in the video, eventually resulting in a group of ten myoblasts closely associated with one another.

Vertebrate myoblasts are the precursor cells of muscle tissue, and when they are grown in culture will often fuse into long multinucleated myotubes over time. Though normally only a small number of cell divisions occur before this morphological change takes place in myoblasts harvested from an embryo, some myoblast cell lines are capable of undergoing the cell cycle ad infinitum when fibroblast growth factor is contained in their culture medium. Elimination of the growth factor can incite differentiation in such cells. The A-10 cells featured in this time-lapse sequence are not fully differentiated, but they do display many of the characteristics of smooth muscle cells, including an obvious tendency to adhere to one another, which is a necessary antecedent to cell fusion.

In the regions where neighboring cells overlap, there appears to be little cytoplasmic activity. The free edges of the myoblasts, however, demonstrate a rapid extension and folding back of lamellipodia and filopodia that result in a flame-like flickering during high speed playback of time-lapse sequences. Known as ruffling, the phenomenon demonstrates an overall rearward movement of cell surface extensions. Accordingly, any particles that adhere to the surface of a motile cell are carried toward the back of that cell by ruffling membranes.

Upon close inspection, vacuoles can be observed migrating from the outer edges of the A-10 myoblasts in this time-lapse sequence to other locations in the cells. The numerous vacuoles likely contain small amounts of culture medium, from which the cells gain nutrients upon digestion. Vacuoles are formed via endocytosis, a cellular ingestion process involving a folding inward of the plasma membrane to convey materials into the cell.