Three major types of neurons: sensory: receives information from the external world and covey this information to the brain via the spinal cord, motor: carry"s signals from spinal cord to the muscles to produce movements. Interneurons: which connect sensory neurons, motor neurons and other interneuron"s. What are neurotransmitters: are released in the synapse. Is a means of communication between cells e. g. , acetylcholine (memory & learning), dopamine (pleasure, movement), serotonin (mood, appetite), norephinephrine (mood, sleep), gaba (inhibition), glutamate (memory) : a neurotransmitter that influences mood and arousal www. notesolution. com: endorphins. : are chemicals that act within the pain pathways and emotion centers of the brain. Somatic nervous system: is a set of verves that conveys information into and out of the central nervous. Autonomic nervous system: is a set of nerves that carries involuntary and automatic commands that control blood vessels, body organs and glands. Sympathetic: (arousing) is the set of nerves that prepares the body for action in threatening situations.