The correct answer is: D) Binding of the neurotransmitter causes chemically gated sodium channels to open in the motor end plate (junctional folds of the sarcolemma) and sodium enters the cell.
The motor neuron cell is connected to muscle cell via synaptic cleft, where neurotransmitter is released. The muscle side of this synapse is called motor end plate. Released neurotransmitter is acetylcholine and it binds to its receptor (ACh receptor) on the motor end plate. As it binds, ion channels open, and Na+ gets into the muscle cell. This event reduces the voltage difference between the inside and outside of the cell and causes depolarization which creates a wave through the entire muscle cell (its membrane-sarcolema). As a consequence, Ca2+ is released from the sarcoplasmic reticulum which will cause the contraction of the muscle cell.
The epicenter of a hypothetical Earthquake is the place where the fault begins to rupture. The tectonic movements within the epicenter is actually the area with the greatest damage after an Earthquake occurs.
The epicenter is the most dangerous zone during an Earthquake because the ground is very much unstable, but as the seismic activity dissipates it is the first one to set and stabilize because this is where the plates will converge.
The correct answer is: [B]: "behavioral" .
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