Academy of Doctors of Audiology. Advanced Beneficiary Notice FAQ. The Advanced Beneficiary Notice of Noncoverage (ABN) is a Medicare document that is used to notify Medicare beneficiaries of their potential financial responsibilities prior to the rendering of a service or the dispensing of an item.
primary sensory neuron. A sensory neuron that is the first in an afferent pathway, beginning at the receptor and ending at a synapse with a secondary sensory neuron, often within a nucleus of the central nervous system. One common type is the pseudounipolar neuron. 1  pseudounipolar neuron.  secondary sensory neuron.
A nerve is a bundle of axons. A sensory neuron is a nerve cell that transmits impulses from a sense receptor such as those in the eye or ear to the brain or spinal cord. A motor neuron is a nerve cell that transmits impulses from the brain or spinal cord to a muscle or gland.A relay neuron connects sensory and motor neurons and is found in the brain or spinal cord (see diagrams 14.1 and 14.2).iagram 14.1 - A motor neuron. The cell body of neurons is usually located in the brain or spinal cord while the axon extends the whole distance to the organ that it supplies. The neuron carrying impulses from the spinal cord to the hind leg or tail of a horse, for example, can be several feet long.