| A | B |
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| nervous system | body system that controls sensation, interpretation, and response; includes the brain, spinal cord, and nerves |
| endocrine system | body system that controls growth, development, and responses to the environment by releasing chemical signals into the bloodstream |
| stimulus | something that causes a physiological response (plural: stimuli) |
| central nervous system (CNS) | part of the nervous system that interprets messages from other nerves in the body; includes the brain and spinal cord |
| peripheral nervous system (PNS) | division of the nervous system that transmits impulses between the central nervous system and other organs in the body |
| neuron | cell of the nervous system that transmits impulses between the body systems as well as interprets and stores some messages in the brain |
| dendrite | branchlike extension of a neuron that receives impulses from neighboring neurons |
| axon | long extension of the neuron membrane that carries impulses from one neuron to another |
| resting potential | difference in electrical charge between the inside and outside of a neuron; contains the potential energy needed to transmit the impulse |
| sodium-potassium pump | active transport protein in neurons that carries sodium (Na+) ions out of the cell and bring potassium (K+) ions into the cell |
| action potential | fast, moving change in electrical charge across a neuron's membrane; also called an impulse |
| synapse | tiny gap between neurons through which chemical signals are sent |
| terminal | end of the neuron's axon from which neurotransmitters are released to stimulate an adjacent cell |
| neurotransmitter | chemical that transmits a nervous system's signal across a synapse |
| rod cell | photoreceptor in the eye that detects light intensity and contributes to black and white vision |
| cone cell | sensory neuron in the eye that detects color |
| hair cell | mechanoreceptor in the inner ear that detects sound waves when bent |
| cerebrum | largest part of the brain, coordinating movement, thought, reasoning, and memory; includes the cerebral cortex and the white matter beneath it |
| cerebral cortex | layer of gray matter on the surface of the cerebrum that receives information and generates responses |
| cerebellum | part of the brain that coordinates and regulates all voluntary muscle movement and maintains posture and balance |
| brain stem | structure that connects the brain to the spinal cord and controls breathing and heartbeat |
| reflex arc | nerve pathway in which an impulse crosses only two synapses before producing a response |
| somatic nervous system | division of the peripheral nervous system that transports signals from the brain to the muscles that produce voluntary movements |
| autonomic nervous system | division of the peripheral nervous system that controls involuntary functions |
| sympathetic nervous system | part of the autonomic nervous system that prepares the body for action and stress |
| parasympathetic nervous system | division of the peripheral nervous system that calms the body and helps the body to conserve energy |
| addiction | uncontrollable physical and mental need for something |
| desensitization | process by which neurons in the brain break down neurotransmitter receptors in response to a larger amount of neurotransmitter in the synapse than usual |
| tolerance | drug resistance that occurs when cells adapt, requiring larger doses of the drug to produce the same effect |
| sensitization | process by which a neuron adds more receptors to its surface in response to consistently lower amounts of a neurotransmitter in the synapse |
| stimulant | drug that increases the number of impulses that neurons generate |
| depressant | drug that causes fewer signals to be transmitted between neurons |
| hormone | chemical signal that is produced in one part of an organism and affects cell activity in another part |
| gland | organ that produces and releases chemicals that affect the activities of other tissues |
| hypothalamus | small area of the midbrain that plays a role in the nervous and endocrine systems |
| pituitary gland | area in the middle of the brain that makes and releases hormones that control cell growth and osmoregulation (water levels in the blood) |
| releasing hormones | chemical that stimulates other glands to release their hormones |
