how many somatic motor neurons stimulate one muscle fiber?

Dorland's Illustrated Medical Dictionary. Language links are at the top of the page across from the title. The least splanchnic nerves that extend from T12 spinal nerves project to and terminate in the prevertebral renal ganglia (not shown here). Some may contain up to 1000 muscle fibers, such as in the quadriceps, or they may only have 10 fibers, such as in an extraocular muscle. Together, the motor neuron and all the muscle fibers that it controls make up a motor unit. [8], Upper motor neurons originate in the motor cortex located in the precentral gyrus. Cleveland Clinic. This neuron releases ACh to a second neuron called a ganglionic neuron that is located in ganglia. Parasympathetic preganglionic fibers exits the medulla oblongata and travel through the glossopharyngeal nerve (CN IX) to the otic ganglion. Many autonomic target effectors have dual innervation by both divisions of the autonomic nervous system, which determines their activity. (Ed. They are referred to as prevertebral because they are anterior to the vertebral column and descending aorta. However, they have different functions. This influence over the appendicular muscles means that the lateral corticospinal tract is responsible for moving the muscles of the arms and legs. There are typically 23 ganglia in the sympathetic chain on either side of the spinal column. These cells in the adrenal medulla release epinephrine and norepinephrine into the bloodstream, rather than using axons to communicate with target structures. The frontal eye fields are responsible for moving the eyes in response to visual stimuli. Webeach motor neuron innervates how many muscle fibers many one motor neuron and all of the muscle fibers it innervates motor unit areas of fine motor control have _____ The number of somatic motor neurons stimulate one muscle fiber are one. Premotor neurons can be 1) spinal interneurons that have cell bodies in the spinal cord, 2) sensory neurons that convey information from the periphery and synapse directly onto motoneurons, 3) descending neurons that convey information from the brain and brainstem. Examples of reflex actions include: Reflex arcs that impact the organs are called autonomic reflex arcs while those that affect the muscles are referred to as somatic reflex arcs. Reflex arcs include sensory nerves that carry signals to the spinal cord, often connect with interneurons there, then immediately transmit signals down the motor neurons to the muscles that triggered the reflex.

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