Final answer:
Transmission of messages in humans occurs through the nervous system via a process called synaptic transmission.
Step-by-step explanation:
Transmission of messages in humans occurs through the nervous system. The nervous system is composed of neurons, which are specialized cells that transmit electrical signals called action potentials. When a message needs to be transmitted from one neuron to another, it is done so through a process called synaptic transmission. In this process, an action potential reaches the end of the presynaptic neuron and triggers the release of neurotransmitters into the synapse, which is the tiny gap between the presynaptic and postsynaptic neurons. The neurotransmitters bind to receptors on the postsynaptic neuron and generate a new action potential, continuing the transmission of the message.