acetylcholine - a neurotransmitter that is part of the autonomic nervous system. Acts on both the central and peripheral nervous system and is used in the motor division of the somatic nervous system. Acts as an inhibitor in cardiac tissue which slows the heart rate. action potential - a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory.
Autonomic Nervous System - is the part of the peripheral nervous system that acts as a control system that functions largely below the level of consciousness to control visceral functions, including heart rate, digestion, respiration rate, salivation, perspiration, pupillary dilation, micturition
(urination), sexual arousal, breathing and swallowing. axon - a long, slender projection of a nerve cell, or neuron, that typically conducts electrical impulses away from the neuron's cell body. brain - an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals—only a few invertebrates such as sponges, jellyfish, adult sea squirts and starfish do not have a brain, even if diffuse neural tissue is present. cell body - The part of a neuron containing the nucleus but not incorporating the axon and dendrites.
Central Nervous System - the part of the nervous system consisting of the brain and spinal cord. cerebellum - a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses cerebrum - the parts of the brain containing the cerebral cortex, as well as several subcortical structures, including the hippocampus, basal ganglia, and olfactory bulb. Controls voluntary functions. dendrite - a short branched extension of a nerve cell, along which impulses received from other cells at synapses are transmitted to the cell body. ganglia - a nerve cell cluster or a group of nerve cell bodies located in the peripheral nervous system. medulla oblongata - the lower half of the brainstem, which is continuous with the spinal cord, the upper half being the pons. Deals with the autonomic (involuntary) functions of breathing, heart rate and blood pressure. mixed nerve - an enclosed, cable-like bundle of axons (the long, slender projections of neurons) in the peripheral nervous system. motor nerve - a nerve that conveys impulses toward or to muscles or glands

nerve impulse - A nerve impulse is an electrical signal that travels along an axon. neuron - an electrically excitable cell that processes and transmits information through electrical and chemical signals. neurotransmitter - are endogenous chemicals that transmit signals across a synapse from one neuron (brain cell) to another 'target' neuron.
Parasympathetic Nervous System - one of the three main divisions of the autonomic nervous system (ANS), the other two being the sympathetic (SNS) and enteric systems.
Peripheral Nervous System - the part of the nervous system that consists of the nerves and ganglia outside of the brain and spinal cord. reflex - an involuntary and nearly instantaneous movement in response to a stimulus. response - An action or movement due to the application of a stimulus. resting potential - as opposed to the specific dynamic electrochemical phenomena called action potential and graded membrane potential. sensory nerve - is an enclosed, cable-like bundle of sensory nerve fibers in the peripheral nervous system. sodium-potassium pump - The pump is an enzyme that transports two potassium ions in exchange for three sodium ions in a reaction driven by hydrolysis of one molecule of ATP to form ATP plus one inorganic phosphate ion. Synonym(s) sodium-potassium ATPase. spinal cord - the cylindrical bundle of nerve fibers and associated tissue that is enclosed in the spine and connects nearly all parts of the body to the brain, with which it forms the central nervous system. stimulus - a