 Dear students, in this topic we shall discuss the neural control of muscle contraction. You know that animal movement involves simultaneous contraction of many muscles and their fibres. These contractions need to be correctly timed and coordinated with respect to one another. The muscle coordination is controlled by the nervous system that sends neuronal impulses which are conducted through the alpha motor neurons to the neuromuscular junctions. The nervous system also regulates the strength of contraction of muscles and also determines the number and type of muscle fibres activated at a time. Dear students, all vertebrate skeletal muscles are innervated by spinal motor neurons. In spinal motor neurons' cell bodies, spinal cord's gray matter's ventral horn is located. The axons of these spinal motor neurons leave through the ventral root. Axons of these motor neurons reach muscles through peripheral nerves. In muscles, they branch off repeatedly. These branches are innervated by skeletal muscle fibres and one neuron's innervates hundreds of skeletal muscles. Dear students, a motor neuron and all the muscle fibres which are innervating these fibres form a motor unit. Dear students, spinal motor neurons hud inputs receiv karte hain 2 triko se. Number one, the sensory motor neurons provide inputs to the spinal motor neurons. These sensory motor neurons innervate the muscle fibres. Dusra source brain se aane wale long tracks interneurons ke hain jo ke spinal motor neurons ko inputs provide karte hain. Dear students, ye jo spinal motor neurons hain, they are the only means for controlling the contraction of muscles. So, they are known as the final common pathway of neural output. Dear students, ye jo synaptic inputs hain, motor neurons may action potential initiate karte hain. These action potentials spread to all of its terminal branches. As a result, they activate all of its end plates jinn ko ye wale fibres innervate karte hain. Dear students, all spinal alpha motor neurons produce the neurotransmitter acetylcholine. Ye jo acetylcholine hain that is released onto all of the terminal fibres in a in a single motor unit. Ek motor unit ke jitne bhi fibres hain un sab me acetylcholine at a time release hoti hain. Iskantee ja ye ke ek motor unit me mojood tamam muscle fibres ek action potential kantee jae me simultaneously contract karte hain. The frequency of action potentials determines whether a single muscle to H or a technique contraction is produced.