A Level Biology Practice Exam

What type of muscle is smooth muscle?

1. Voluntary muscle that requires conscious thought

2. Involuntary muscle that contracts without conscious thought

3. Skeletal muscle that aids in movement

4. Cardiac muscle found only in the heart

The correct answer is: Involuntary muscle that contracts without conscious thought

Smooth muscle is indeed categorized as involuntary muscle, meaning it operates without conscious control. This type of muscle is found in various internal structures, such as the walls of hollow organs like the intestines, blood vessels, and the bladder. Its contractions are automatic and regulated by the autonomic nervous system, allowing for critical functions like digestion and regulation of blood flow to occur seamlessly. Smooth muscle cells are spindle-shaped and unique in that they do not have the striations seen in skeletal and cardiac muscle, which reflects their different functional roles in the body. The ability of smooth muscle to contract rhythmically and sustain contractions over longer periods is essential for the physiological processes that keep our organs functioning without the need for conscious awareness.