Definition

Noun: A nerve fiber that transmits signals from the central nervous system to muscles or glands, causing them to contract or secrete.

Usage

This is a specialized anatomical and physiological term. It refers to the specific part of a neuron (nerve cell) that carries outgoing commands, known as efferent impulses. It is the opposite of a sensory fiber.

Examples

• Noun:
  • Damage to the motor fibers can result in paralysis of the affected muscle.
  • The signal travels along the motor fiber to stimulate the gland.
  • The neurologist tested the function of the patient's motor fibers.

Advanced Usage

• "Lower motor fibers": Refers to motor fibers whose cell bodies are located in the spinal cord or brainstem and that directly innervate muscles.
• "Upper motor fibers": Refers to motor fibers that originate in the brain's motor cortex and carry signals down to connect with lower motor neurons.

Variants and Related Words

• Motor neuron (n): A nerve cell that includes a motor fiber (axon) as part of its structure.
• Efferent fiber (n): A synonym for motor fiber, emphasizing its function of carrying signals from the central nervous system.
• Motor nerve (n): A bundle of many motor fibers (axons) bound together within a nerve trunk.

Synonyms

• Efferent nerve fiber: The formal synonym, highlighting the direction of impulse conduction.
• Motoneuronal axon: A more technical term specifying the part of the motor neuron.

Related Phrases

• Motor unit: A single motor neuron and all the muscle fibers it innervates.
• Motor pathway: The route or tract formed by chains of motor fibers/neurons from the brain to the muscle.

Noun

1. a nerve fiber that carries impulses toward the muscles or glands