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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]
Betz cells (also known as pyramidal cells of Betz) are giant pyramidal cells located within the fifth layer of the grey matter in the primary motor cortex.These neurons are the largest in the central nervous system, sometimes reaching 100 μm in diameter.
In that view, a neuron in the motor cortex sends an axon or projection to the spinal cord and forms a synapse on a motor neuron. The motor neuron sends an electrical impulse to a muscle. When the neuron in the cortex becomes active, it causes a muscle contraction. The greater the activity in the motor cortex, the stronger the muscle force.
A neuroeffector junction is a site where a motor neuron releases a neurotransmitter to affect a target—non-neuronal—cell. This junction functions like a synapse.However, unlike most neurons, somatic efferent motor neurons innervate skeletal muscle, and are always excitatory.
Nervous tissue, also called neural tissue, is the main tissue component of the nervous system.The nervous system regulates and controls body functions and activity. It consists of two parts: the central nervous system (CNS) comprising the brain and spinal cord, and the peripheral nervous system (PNS) comprising the branching peripheral nerves.
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 ...
Central pattern generators are groups of neurons in the spinal cord that are responsible for generating stereotyped movement. It has been shown that in cats, rhythmic activation patterns are still observed following removal of sensory afferents and removal of the brain., [1] indicating that there is neural pattern generation in the spinal cord independent of descending signals from the brain ...
Corticospinal neurons synapse directly onto alpha motor neurons for direct muscle control. Betz cells are very large cells that are very visible under a microscope, and while they account for only about 5% of cells projecting to the spinal cord, they are often considered most crucial for communication of motor signals. [2]