noun, plural: efferent neurons
Depending on the associated direction of nerve impulses, neurons may be efferent or afferent. Neurons that transmit nerve impulses peripherally, i.e. away from the central nervous system are referred to as efferent neurons. In contrast, neurons that relay nerve impulses towards the central nervous system are called afferent neurons. A chain of efferent neurons makes an efferent nerve. Motor neurons, particularly the lower motor neurons, are regarded as efferent neurons because they carry nerve impulses from the central nervous system. In general, motor neurons are neurons in which their cell body is in the spinal cord whereas their axon are projecting outside the spinal cord and innervate muscles or glands. They effect or produce movement to the target muscle cell while secretion to the target gland. In vertebrates, the lower motor neurons stimulate muscle fibers by releasing neurotransmitters at the neuromuscular junction. They may also effect many action potentials in a muscle fiber, such as in the case of summation or tetanus.
Word origin: Latin efferēns, efferō (bring or carry out), from ē (out of), short form of ex, + ferō (carry)
- efferent neurone