Final answer:
The synchronization of adjacent smooth muscle cells is due to gap junctions that allow these cells to contract as a single unit, which is essential for the function of organs with visceral muscle.
Step-by-step explanation:
The synchronization of adjacent smooth muscle cells reflects the ability of these cells to work in unison to coordinate contractions, particularly in single-unit smooth muscle tissue. This tissue type contains gap junctions which allow for the synchronization of membrane depolarization and contractions. As a result, the muscle contracts as a coordinated single unit, which is crucial in the functioning of visceral muscles found in the walls of organs. These muscles exhibit a stress-relaxation response that allows an organ to expand, contract, and relax smoothly. On the other hand, multiunit smooth muscle cells, which lack gap junctions, do not synchronize and contract individually in response to stimulation from autonomic nerves or hormones.
It's important to recognize that smooth muscle contraction, just like in skeletal muscle, is driven by the sliding of actin-myosin filaments. However, due to the lack of striations and a differently organized arrangement of these filaments in smooth muscle, the tissue has a uniform, nonstriated appearance, thus being named 'smooth muscle'. Despite its appearance, smooth muscle effectively regulates vital functions, such as blood pressure regulation by arterial walls and material movement through the body's internal passageways.