Final answer:
A nerve impulse is typically transmitted across a synapse from a presynaptic to a postsynaptic cell via the release of neurotransmitters, which bind to receptors on the postsynaptic neuron to elicit a response.
Step-by-step explanation:
A nerve impulse is usually transmitted across a synapse from a presynaptic to a postsynaptic cell via neurotransmitters. This process occurs at a chemical synapse, where the presynaptic neuron releases neurotransmitter chemicals into the synaptic cleft, which then travel across to the postsynaptic neuron and bind to specific receptors on its membrane. This binding can generate a postsynaptic potential, leading to an action potential if the threshold is reached and thereby transmitting the signal to the next neuron.
Transmission at an electrical synapse, conversely, involves a direct connection that allows ions to pass between neurons. However, the majority of synapses in the human nervous system are chemical synapses, making neurotransmitter release the most common mechanism for nerve impulse transmission in humans. Neurotransmitters can have various effects on the postsynaptic cell, including excitatory or inhibitory influences on the generation of action potentials.