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