- Broca's area: controls language expression
- Wernicke's area: controls language reception
- acetylcholine: neurotransmitter that enables learning and memory and also triggers muscle contraction
- action potential: neural impulse; a brief electrical charge that travels down an axon
- adrenal glands: pair of endocrine glands just above the kidneys; secretes adrenaline and arouses body in times of stress
- amygdala: two lima bean-sized neural clusters that are components of the limbic system and are linked to emotion
- aphasia: impairment of language, usually caused by left hemisphere damage either to Broca's area or Wernicke's area
- association areas: areas of the cerebral cortex not involved in primary motro or sensory functions
- autonomic nervous system: part of the peripheral nervous system that controls the glands and the muscles of the internal organs; sympathetic, parasympathetic
- axon: extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands
- brainstem: oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skills; survival functions
- central nervous system: the brain and the spinal cord
- cerebellum: "little brain" attached to the rear of the brainstem; movement output and balance
- cerebral cortex: intricate fabric of interconnected neural cells that covers the cerebral hemispheres
- corpus callusum: large band of neural fibers connecting two brain hemispheres and carrying mesages between them
- dendrite: the bushy, branching extensions of a neuron that receiv messages and conduct impulses toward the cell body
- endocrine system: body's "slow" chemical communication system; set of glands that secrete hormones into the bloodstream
- endorphins: "morphine within"- natural, opiatelike neurotransmitters linked to pain control and to pleasure
- frontal lobes: portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements; personality, judgements
- glial cells: cells in the nervous system that support, nourish, and protect neurons
- hormones: chemical messengers, mostly those manufactured by the endocrine glands, that are produced in one tissue and affect another
- hypothalamus: neural structure that maintains activities (eating, drinkin, body temperature)
- interneurons: central nervous system neurons that internally communicate and intervene between the sensory inputs and motor outputs
- lesion: tissue destruction
- limbic system: doughnut-shaped system of neural structures associated with emotions such as fear and aggression, and drives such as those for food and sex
- medulla: base of the brainstem; controls heartbeat and breathing
- motor cortex: area at the rear of the frontal lobes that controls voluntary movements
- motor neurons: neurons that carry outgoing information from the central nervous system to the muscles and glands
- myelin sheath: layer of fatty tissure segmentally encasing the fibers of many neurons; enables faster transmissions of neural impulses
- nerves: neural "cables" containing many axons
- nervous system: body's speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous system
- neural networks: interconnected neural cells
- neuron: a nerve cell; the basic building block of the nervous system
- neurotransmitters: chemical messengers that traverse the synaptic gaps between neurons
- occipital lobe: portion of the cerebral cortex lying at the back of the head; visual areas
- parasympathetic system: division of the autonomic nervous system that calms the body, conserving its energy
- parietal lobe: portion off the cerebral cortex lying at the top of the head and toward the rear; touch and body position
- peripheral nervous system: sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body
- pituitary gland: endocrine system's most influential gland; regulates growth and controls other endocrine glands
- plasticity: brain's capacity for modification, as evident in brain reorganization following damage
- reflex: simple, automatic, inborn response to a sensory stimulus, such as the knee-jerk response
- reticular formation: nerve network in the brainstem that plays an important role in controlling arousal
- sensory cortex: area at the front of the parietal lobes that registers and processes body touch and movement sensations
- sensory neurons: neurons that carry incoming information from the sense receptors to the central nervous system
- somatic nervous system: division of the peripheral nervous system that controls the body's skeletal muscles' skeletal nervous system
- split brain: condition in which the two hemispheres of the brain are isolated by cutting the connecting fibers between them
- sympathetic nervous system: division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations
- synapse: junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron.
- temporal lobes: portion of the cerebral cortex lying roughly above the ears; auditory areas
- thalamus: brain's sensory switchboard, located on top of the brainstem
- threshold: level of stimulation required to trigger a neural impulse