Final answer:
Nerve impulses are conducted along an axon and are transmitted to the next neuron or cell at synapses using chemical neurotransmitters. These neurotransmitters are released in response to an action potential, crossing the synaptic cleft and binding to receptors on the postsynaptic cell, which may then carry the nerve impulse.
Step-by-step explanation:
Nerve impulses are how neurons communicate and lead to actions such as muscle movement or the sensation of touch. In a neuron, an electrical signal called an action potential travels along the axon until it reaches the end, or axon terminal. At this point, the neuron comes in close proximity to another neuron or cell, but they do not physically touch. The gap between them is called the synapse. When the action potential reaches the axon terminal, it causes synaptic vesicles to release neurotransmitters into the synapse. These chemical messengers then travel across the synaptic cleft and bind to receptors on the membrane of the postsynaptic cell. Upon binding, the neurotransmitters stimulate the next neuron or muscle cell to propagate the nerve impulse or induce an action.
Neurotransmitters have different effects on the postsynaptic cell, and they can be excitatory or inhibitory, either promoting or preventing the generation of a new action potential in the postsynaptic neuron. This precise process is crucial for the functioning of the nervous system, coordinating everything from simple reflexes to complex thoughts.