Neurotransmitters

Question

Neurotransmitters
A) are released by the postsynaptic neuron
B) are distributed randomly throughout the nervous system
C) can diffuse back into the synaptic knob
D) all of the above

Accepted Answer

Neurotransmitters are released by the presynaptic neuron, cross the synaptic cleft, and bind to receptors on the postsynaptic neuron. However, some neurotransmitters can diffuse back into the synaptic knob, which is known as reuptake, to be reused in a subsequent release. Therefore, option C is the correct answer as it correctly describes one of the functions of neurotransmitters. Option A is incorrect because neurotransmitters are released by the presynaptic neuron, not the postsynaptic neuron. Option B is incorrect because neurotransmitters are not distributed randomly throughout the nervous system but are released at specific synapses where they are required.