The motor unit consists of muscle fibers and a:

• A. neuroglial cell
• B. sensory neuron
• C. capillary
• D. motor neuron

Answer: (D)

Verified step by step guidance

1. Understand the concept of a motor unit: A motor unit is the functional unit of the neuromuscular system, consisting of a motor neuron and all the muscle fibers it innervates. This allows for coordinated muscle contraction.
2. Review the role of a motor neuron: A motor neuron is a type of nerve cell that transmits signals from the central nervous system to skeletal muscles, initiating muscle contraction.
3. Eliminate incorrect options: Neuroglial cells provide support and protection for neurons but are not involved in forming motor units. Sensory neurons transmit sensory information to the central nervous system and are not part of motor units. Capillaries are small blood vessels that supply oxygen and nutrients to tissues but are not directly involved in the motor unit.
4. Identify the correct answer: The motor neuron is the component that, along with muscle fibers, forms the motor unit.
5. Conclude: The motor unit consists of muscle fibers and a motor neuron, which work together to produce muscle contractions in response to neural signals.