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In order for muscle contraction to occur, cross-bridges form between: actin and myosin. At neuromuscular junctions, acetylcholine binds to ______. receptors in the muscle fiber membrane. The functional connection between a neuron and a muscle cell is called a. neuromuscular junction.
The neuromuscular junction accomplishes this by turning the electrical signal from the nervous system into a chemical signal that can be moved across the synaptic cleft. The chemical in this case is acetylcholine (ACh), an example of a neurotransmitter that allows neurons to communicate with other cells.
Neuromuscular junctions are excitatory chemical synapses that use acetylcholine as the neurotransmitter. Neuromuscular junctions form between nerve terminals of spinal cord motor neurons and skeletal muscles and are covered by perisynaptic Schwann cells and kranocytes.
As a result, acetylcholine floods the synaptic cleft, where it can reach the postsynaptic membrane by diffusion. Acetylcholine binds to acetylcholine receptors, also called nicotinic acetylcholine receptors. These are present in the many folds of the postsynaptic membrane (the sarcolemma).
Acetylcholine has different roles and functions at different synapses throughout the body. In the somatic nervous system, acetylcholine is used at the neuromuscular junctions, triggering the firing of motor neurons and affecting voluntary movements.
Different vesicular (SNAP-25, syntaxin) and nerve terminal membrane proteins (synaptobrevin and synaptotagmin) play a role in the fusion of SVs to active zones and exocytosis of ACh into the synaptic cleft. The released ACh subsequently binds to nicotinic ACh receptors on the junctional folds of the motor endplate.
In vertebrates, the acetylcholine receptor subtype that is found at the neuromuscular junction of skeletal muscles is the nicotinic acetylcholine receptor (nAChR), which is a ligand-gated ion channel.
The neuromuscular junction (NMJ) is the connecting area between the end of a motor neuron and a muscle. It is here that the acetylcholine-dependent nerve impulse (action potential) is transmitted from neuron to muscle – hence the term neuromuscular.
Neuromuscular junction (NMJ) is responsible for the chemical transmission of the electrical impulse from a nerve to the muscle( skeletal/ smooth/ cardiac) in order to produce an appropriate muscle contraction.
Upon stimulation by a nerve impulse, the terminal releases the chemical neurotransmitter acetylcholine from synaptic vesicles. Acetylcholine then binds to the receptors, the channels open, and sodium ions flow into the end plate. This initiates the end-plate potential, the electrical event that leads to contraction of the muscle fibre.