| A | B |
|---|
| central nervous system | the brain and the spinal cord |
| endocrine system | the chemical regulator of the body, composed of the glands that secrete hormones |
| nervous system | a collection of hundreds of billions of specialized cells that transmit information between different parts of the body |
| peripheral nervous system | the nerves that link the CNS to the skin,muscles, and glands |
| action potential | a change in electrical charge that occurs in a neuron when a nerve impulse is transmitted |
| agonist | a drug that has chemical properties similar to a particular neurotransmitter and thus mimics the effects of the neurotransmitter |
| antagonist | a drug that reduces or stops the normal effects of a neurotransmitter |
| axon | the part of the neuron that transmits information away from the cell body toward other neurons |
| dendrite | the part of the neuron that collects information away from the cell body toward other neurons |
| myelin sheath | a layer of fatty tissue surrounding the axon of a neuron that acts as an insulator and allows faster transmission of the electrical signal |
| neuron | one of the more than 100 billion cells in the nervous system |
| neurotransmitters | a chemical that relays signals across the synapses between neurons |
| node of ranvier | the break in the myelin sheath of a nerve fiber |
| resting potential | a state in which the interior of the neuron contains a greater number of negatively charged ions than does the area outside the cell |
| reuptake | the process in which the neurotansmitters in the synapse are reabsorbed into the transmitting terminal buttons |
| soma | the part of the neuron that contains the nucleus of the cell and that keeps the cell alive |
| synapses | the small gap between neurons across which nerve impulses are transmitted |
