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It allows the motor neuron to transmit a signal to the muscle fiber, causing muscle contraction. [2] Muscles require innervation to function—and even just to maintain muscle tone, avoiding atrophy. In the neuromuscular system, nerves from the central nervous system and the peripheral nervous system are linked and work together with muscles. [3]
The acoustic reflex (also known as the stapedius reflex, [1] stapedial reflex, [2] auditory reflex, [3] middle-ear-muscle reflex (MEM reflex, MEMR), [4] attenuation reflex, [5] cochleostapedial reflex [6] or intra-aural reflex [6]) is an involuntary muscle contraction that occurs in the middle ear in response to loud sound stimuli or when the person starts to vocalize.
Efferent nerve fibers carry motor nerve signals from the anterior horn to the muscles Effector muscle innervated by the efferent nerve fiber carries out the response. A reflex arc, then, is the pathway followed by nerves which (a.) carry sensory information from the receptor to the spinal cord, and then (b.) carry the response generated by the ...
Groups of motor units often work together as a motor pool to coordinate the contractions of a single muscle. The concept was proposed by Charles Scott Sherrington. [2] Usually muscle fibers in a motor unit are of the same fiber type. [3] When a motor unit is activated, all of its fibers contract.
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.
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]
The amygdala is known to have a role in the "fight-or-flight response", and the hippocampus functions to form memories of the stimulus and the emotions associated with it. [13] The role of the BNST in the acoustic startle reflex may be attributed to specific areas within the nucleus responsible for stress and anxiety responses. [ 12 ]
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 ...