In humans, transmission of nerve impulses across a synaptic cleft is carried out by neurotransmitter.
Step-by-step explanation:
In humans, nerve impulses are carried out by neurotransmitter diffusion. Communication between the cells occur through the small gap called the synapses.
The transmission happens through the neurotransmitter which helps by diffusing across the synaptic cleft and binding the receptor molecule to the synaptic membrane hence sharing information and transmitting them.
The chemical found inside the neuron is responsible and it is depolarized within the neuron and sent as an information by the synaptic receptors transmitted by the neurotransmitter .