Definition

1. Noun:
   • A nerve fiber that carries impulses toward the muscles or glands: An "efferent fiber" is a type of nerve fiber (axon) that transmits motor commands or signals away from the central nervous system (the brain and spinal cord) to effector organs, such as muscles or glands, to stimulate action.

Examples of Usage

• Noun:
  • The sciatic nerve contains both afferent and efferent fibers.
  • Damage to the efferent fibers can result in paralysis of the affected muscles.
  • The signal travels along an efferent fiber to stimulate the salivary gland.

Advanced Usage

• In neuroanatomy: The term is often used in contrast to "afferent fiber." While efferent fibers carry signals to effectors, afferent fibers carry sensory signals to the central nervous system.
  • The reflex arc involves a sensory afferent fiber and a motor efferent fiber.

Variants and Related Words

• Efferent (adj): Conducting or carrying outward or away from a central structure. Often used to describe nerves or pathways.
  • The efferent pathway of the autonomic nervous system.
• Efferent neuron (n): A neuron whose axon is an efferent fiber; a motor neuron.
  • The cell body of the efferent neuron is located in the spinal cord.
• Motor fiber (n): A common synonym for efferent fiber, emphasizing its role in causing movement.
  • The motor fibers control the contraction of skeletal muscle.

Synonyms

• Motor fiber: A nerve fiber that carries impulses to muscles.
• Efferent nerve fiber: A more formal, equivalent term.
• Efferent axon: Specifically denotes the elongated projection of a neuron that functions as an efferent fiber.

Related Phrases / Compound Terms

• Efferent pathway: The route formed by efferent fibers from the central nervous system to an effector.
  • The efferent pathway for the pupillary light reflex is complex.
• Efferent division: Refers to the part of the peripheral nervous system composed of efferent neurons and fibers.
  • The efferent division is subdivided into somatic and autonomic systems.

Notes on Meaning

• The core concept is directionality: efferent means "conducting outward." Therefore, an "efferent fiber" is defined by its function of carrying neural commands the central nervous system to produce an effect (e.g., muscle contraction, gland secretion). It is a fundamental component of the motor system.

Noun

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