Kaplan Nursing Entrance Exam Practice 2025 – Comprehensive Prep

Smooth muscle is characterized as involuntary and is prominently found in the walls of various organs. Unlike skeletal muscle, which is under conscious control and typically found attached to bones to facilitate movement, smooth muscle operates without conscious thought. This muscle type plays a crucial role in various physiological processes, such as peristalsis in the gastrointestinal tract, regulation of blood vessel diameter, and controlling the flow of air through the respiratory system.

Smooth muscle fibers are non-striated and have a single nucleus, which differentiates them from skeletal muscle fibers that are striated and multinucleated. This unique structure allows smooth muscle to contract in a more sustained and rhythmical way, making it well-suited for its role in involuntary movements that's necessary for maintaining homeostasis within the body's organs.

In contrast, cardiac muscle, while also involuntary, is specifically found only in the heart and is responsible for pumping blood. Skeletal muscle, as previously mentioned, is under voluntary control, and connective tissue primarily serves to support and bind other tissues and organs rather than facilitating movement. Thus, smooth muscle's involuntary nature and location in the walls of organs make it the correct answer in this context.