Gourt > Health > Conditions and Diseases > Neurological Disorders > Peripheral Nervous System > Neuromuscular Junction Diseases (2)
A neuromuscular junction is the synapse or junction of the axon terminal of a motoneuron with the motor end plate, the highly-excitable region of muscle fiber plasma membrane responsible for initiation of action potentials across the muscle's surface, ultimately causing the muscle to contract. The signal passes through the neuromusclar junction via the neurotransmitter acetylcholine.
Anatomy
Motor neuron (efferent) axons originating in the spinal cord contact muscle fibers via a structure known as the motor endplate. Here, motor neuron axons lose their myelin sheath and branch into multiple endings, which occupy depressions in the sarcolemma. Motor neurons can innervate from one to over 100 muscle fibers, but each muscle fiber receives only inputs from only one motor neuron. In the terminal branches of the motor nerve, structures known as presynaptic active zones accumulate synaptic vesicles filled with the neurotransmitter acetylcholine. On the muscle side of the junction, the muscle fiber is folded into grooves called postjunctional folds that mirror the presynaptic active zones, the spaces between the folds contain acetylcholine receptors. The muscle surface is covered by the synaptic basal lamina. Postjunctional folds are characteristic of skeletal muscle, particularly in fast muscle fibers.
Mechanism of Action
More on [ Neuromuscular junction ]
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Disorders of the Neuromuscular Junction - An introduction to disorders of the neuromuscular junction from Baylor College of Medicine.
Lincolnshire Post-Polio Library: Neuromuscular Junction Transmission Defects - Article about anticholinesterase-responsive neuromuscular junction transmission defects in post-poliomyelitis fatigue.
Meta Description: [ Lincolnshire Post-Polio Library [Anticholinesterase-responsive neuromuscular junction transmission defects in post-poliomyelitis fatigue] Disabling generalized fatigue and muscle fatiguability are common features of post-poliomyelitis syndrome (PPS). ]
Neuromuscular Disease Center - Review of various muscle, nerve and neuromuscular disorders; links to relevant sites.
Meta Description: [ fellowship, muscle, nerve, myopathy, neuropathy, ataxia, cerebellar, spinal, antibody, neuromuscular, dystrophy, pain, hereditary, immune, biopsy, als, motor, sensory, autonomic, ion, channel, trophic, pathology, gm1, mag, sulfatide, toxin, axon, alan pestronk, myositis, spastic, paraplegia, dise... ]
Neuromuscular Junction Effects - Description of acetylcholinesterase inhibitors producing destructive changes at the neuromuscular junction. For medical professionals.
Sofija Kelic: Effects of Virus Infection of the Neuromuscular Junction in Vitro. - From the Karolinska Institutet in Sweden, an article about how toxic and infectious agents can disturb normal development of the neuromuscular junction.
