all the motor neurons that control the skeletal muscles are
efferent nerves Somatic motor neurons Somatic
title: Motor neuron text: categories: Somatic motor neurons originate in the central nervous system, project their axons to skeletal muscles (such as the muscles of the limbs, abdominal, and intercostal muscles), which are involved in locomotion. The three types of these neurons are the "alpha efferent neurons", "beta efferent neurons", and "gamma efferent neurons". They are called efferent to indicate the flow of information from the central nervous system (CNS) to the periphery. In addition to voluntary skeletal muscle contraction, alpha motor neurons also contribute to muscle tone, the continuous force generated by noncontracting muscle to oppose stretching. When a muscle is stretched, sensory title: Acetylcholine text: heart, lungs, upper gastrointestinal tract, and sweat glands. Acetylcholine is the substance the nervous system uses to activate skeletal muscles, a kind of striated muscle. These are the muscles used for all types of voluntary movement, in contrast to smooth muscle tissue, which is involved in a range of involuntary activities such as movement of food through the gastrointestinal tract and constriction of blood vessels. Skeletal muscles are directly controlled by motor neurons located in the spinal cord or, in a few cases, the brainstem. These motor neurons send their axons through motor nerves, from which they emerge to connect title: Upper motor neuron text: Upper motor neuron Upper motor neurons (UMNs) are the main source of voluntary movement. They are found in the brain and carry motor information down the spinal cord to activate the lower motor neurons, which in turn directly signal muscles to contract. They are a type of giant pyramidal cell called "Betz cells" and are found just below the surface of the cerebral cortex within layer V of the primary motor cortex. The cell bodies of "Betz cell" neurons are the largest in the brain, approaching nearly 0.1mm in diameter. The primary motor cortex, or precentral gyrus, is one of title: Motor neuron text: PNS, which synapses onto the muscle. All vertebrate motor neurons are cholinergic, that is, they release the neurotransmitter acetylcholine. Parasympathetic ganglionic neurons are also cholinergic, whereas most sympathetic ganglionic neurons are noradrenergic, that is, they release the neurotransmitter noradrenaline. (see Table) Motor neuron A motor neuron (or motoneuron) 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. There are two types of motor neuron – upper title: Motor pool (neuroscience) text: each motor pool is tightly controlled by complex developmental pathways. Distinct skeletal muscles are controlled by groups of individual motor units. Such motor units are made up of a single motor neuron and the muscle fibers that it innervates. Motor neurons are located in the ventral horn of the spinal cord and the brainstem. These neurons innervate skeletal muscle fibers through the propagation of action potentials down their axons (through ventral roots and cranial nerves), and they stimulate skeletal muscle fibers at neuromuscular junctions where they synapse with the motor end plates of muscle fibers. In humans, these axons can