Question

Which is not true of a synapse?
A. Neurotransmitters affect postsynaptic neurons
B. Many neurons may be involved
C. A synaptic cleft separates the neurons of the synapse
D. Neurotransmitters are released from dendrites

Answer 1

Neurons use action potential to transmit signals along the axon to the synaptic terminals. Neurotransmitters are released into the axon terminal into the synapse for the purpose of signal transmission.

Complete answer:
The cell body of a neuron is like a typical cell, consisting of a nucleus, mitochondria and other cell organelles. From the cell body, numerous filaments extrude, these are called dendrites. The elongated projections called axons extend out to form synaptic knobs. The axon is covered by a myelin sheath. The myelin sheath helps in the smooth conduction of a nerve impulse. The space between the axon terminal of a neuron (presynaptic neuron) and the dendrites of the following neuron (postsynaptic neuron) is called a synapse. In this space, only the neurotransmitters of the presynaptic neuron get released and reach their respective receptors present on the postsynaptic neuron membrane. Neurotransmitters are retained in the axon terminal's synaptic vesicles and are released into the synaptic cleft. The nerve impulse is transmitted in the form of electrical or chemical signals. It works in association with the central and peripheral nervous system.

So, the correct answer is option D.

Note: Cells of the central nervous system are called neurons. These are unique in many ways and different from other somatic cells. It has an indefinite and elongated shape. Cell body, axon and dendrites are the parts of a neuron. The nerve cells that are stimulated by sensory feedback from the environment are sensory neurons.