The surfaces of a pair of the 3T3 cells appear to boil, but the rapid bubbling is in reality the result of rapid changes in the actin cortices of the cells rather than exposure to heat. The hemispherical mounds that quickly appear and recede are called blebs. Remnants of the spherical form that fibroblast cells typically assume when they are first placed in a culture dish or are preparing to divide, blebs generally completely disappear when the cells fully spread out over the substratum.

The cell on the left in the first part of this time-lapse sequence extends a skirt of lamellipodia around its periphery more quickly than the cell on the right, which undergoes a lengthy series of contortions. Accordingly, the cell on the left-hand side correspondingly experiences a swifter decrease in the number of blebs upon its surface. The entire cycle of a cell developing spherical geometry, dividing, undergoing a flurry of bleb formation and recession, and finally flattening on the chamber surface can subsequently be observed several times in the video.

Once the fibroblasts are allowed to settle on the substratum, their large nuclei can be easily observed. Each nucleus is surrounded by an abundance of mitochondria, which exhibit a granular appearance during the high speed playback of the time-lapse sequence. The outlines of the multiple nucleoli contained inside the nuclei are much clearer than those of the mitochondria, which are much smaller in size.

Fibroblast locomotion often involves the extension of both lamellipodia and filopodia, which are small, narrow surface projections. Filopodia can also be utilized by an animal cell, however, to explore its environment. In such instances, the finger-like structures, which may be extended in multiple directions at any single moment, serve as feelers that provide environmental information to the body of the cell. This new data sometimes causes the cell to modify its migratory path or alter its morphology. Some cells exploit the sensory capabilities of filopodia to detect and capture bacteria or other foreign materials.