Final answer:
The axon is the tail-like structure in a neuron responsible for carrying electrical signals to target cells, possibly being insulated by the myelin sheath and ending at axon terminals where it synapses with other cells.
Step-by-step explanation:
The tail-like portion of a neuron upon which electrical signals are carried is called the axon. The axon transmits electrical signals from the neuron's cell body, or soma, to target cells. Neurons can be myelinated, where an insulating layer known as the myelin sheath surrounds the axon to increase the speed of signal transmission. At the end of the axon are axon terminals or terminal buttons which contain synaptic vesicles. These vesicles house neurotransmitters, which are released into the synapse, the gap between nerve cells, to communicate with other neurons or target cells like muscles or glands.