Which is not a feature of Skeletal muscle
**Core Concept**
Skeletal muscle is a type of striated muscle that is attached to bones and plays a crucial role in movement, posture, and locomotion. It is characterized by its multinucleated fibers, striated appearance under the microscope, and its ability to contract and relax.
**Why the Correct Answer is Right**
Skeletal muscle exhibits several key features, including voluntary control, striated appearance, multinucleated fibers, and a high concentration of mitochondria. These characteristics are essential for its role in movement and energy production. The correct answer is a feature that does not align with these characteristics.
**Why Each Wrong Option is Incorrect**
**Option A:** Multinucleated fibers - This is a feature of skeletal muscle, as it arises from the fusion of multiple myoblasts during development.
**Option B:** Striated appearance - This is also a feature of skeletal muscle, as it is composed of myofibrils that are arranged in a regular pattern, giving it a striated appearance under the microscope.
**Option C:** Ability to contract and relax - This is a fundamental property of skeletal muscle, as it is designed to move bones and maintain posture.
**Option D:** Autonomic control - This is not a feature of skeletal muscle, as it is primarily under voluntary control, with some involuntary control via the autonomic nervous system, but not in the same way as smooth muscle.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that skeletal muscle is composed of two types of fibers: slow-twitch (Type I) and fast-twitch (Type II). Slow-twitch fibers are more fatigue-resistant and are involved in endurance activities, while fast-twitch fibers are more powerful but fatigue quickly and are involved in explosive activities.
**Correct Answer: D. Autonomic control**