Search results
Results From The WOW.Com Content Network
A motor neuron (or motoneuron or efferent neuron[1]) is a neuron whose cell body is located in the motor cortex, brainstem or the spinal cord, and whose axon (fiber) projects to the spinal cord or outside of the spinal cord to directly or indirectly control effector organs, mainly muscles and glands. [2] There are two types of motor neuron ...
The brain is the central organ of the human nervous system, and with the spinal cord makes up the central nervous system. It consists of the cerebrum, the brainstem and the cerebellum. The brain controls most of the activities of the body, processing, integrating, and coordinating the information it receives from the sense organs, and making ...
Upper motor neuron. Upper motor neurons (UMNs) is a term introduced by William Gowers in 1886. They are found in the cerebral cortex and brainstem and carry information down to activate interneurons and lower motor neurons, which in turn directly signal muscles to contract or relax. UMNs represent the major origin point for voluntary somatic ...
The first-order neurons are sensory neurons located in the dorsal root ganglia, that send their afferent fibers through the two dorsal columns. [3] The first-order axons make contact with second-order neurons of the dorsal column nuclei (the gracile nucleus and the cuneate nucleus) in the lower medulla. The second-order neurons send their axons ...
Glutamate released from the upper motor neurons triggers depolarization in the lower motor neurons in the anterior grey column, which in turn causes an action potential to propagate the length of the axon to the neuromuscular junction where acetylcholine is released to carry the signal across the synaptic cleft to the postsynaptic receptors of the muscle cell membrane, signaling the muscle to ...
A gamma motor neuron (γ motor neuron), also called gamma motoneuron, or fusimotor neuron, is a type of lower motor neuron that takes part in the process of muscle contraction, and represents about 30% of (Aγ) fibers going to the muscle. [1][2] Like alpha motor neurons, their cell bodies are located in the anterior grey column of the spinal cord.
Motor nerve. A motor nerve, or efferent nerve, is a nerve that contains exclusively efferent nerve fibers and transmits motor signals from the central nervous system (CNS) to the muscles of the body. This is different from the motor neuron, which includes a cell body and branching of dendrites, while the nerve is made up of a bundle of axons.
Alpha motor neurons are derived from the basal plate (basal lamina) of the developing embryo. Alpha (α) motor neurons (also called alpha motoneurons), are large, multipolar lower motor neurons of the brainstem and spinal cord. They innervate extrafusal muscle fibers of skeletal muscle and are directly responsible for initiating their contraction.