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64 Cards in this Set
- Front
- Back
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absolute refractory period
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The brief time interval following an action potential when a neuron is incapable of being stimulated to fire another impulse.
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acetylcholine (ACh)
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An excitatory neurotransmitter that operates at synapses with muscles and is also the transmitter in some neural networks involved in memory.
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action potential
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A nerve impulse resulting from the depolarization of an axon’s cell membrane
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adrenal glands
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Endocrine glands that release stress hormones, including catecholamines and corticosteroids
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agonist
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A drug that increases or mimics the activity of a neurotransmitter.
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all-or-none law
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States that an action potential is not proportional to the intensity of stimulation; either a neuron fires with maximum intensity or it does not fire (compare with graded potential ).
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amygdala
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A limbic system structure that helps organize emotional response patterns.
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antagonist
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A drug that inhibits or decreases the action of a neurotransmitter.
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aphasia
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The partial or total loss of ability to understand speech (receptive aphasia) or to produce it (productive aphasia).
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association cortex
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The areas of the cerebral cortex that do not have sensory or motor functions but are involved in the integration of neural activity that underlies perception, language, and other higher-order mental processes.
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autonomic nervous system
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The branch of the peripheral nervous system that activates the body’s involuntary muscles (e.g., heart) and internal organs.
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axon
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An extension from one side of the neuron cell body that conducts nerve impulses to other neurons, muscles, or glands.
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brain stem
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The portion of the brain formed by the swelling of the spinal cord as it enters the skull; its structures regulate basic survival functions of the body, such as heart rate and respiration.
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Broca’s area
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A region of the left frontal lobe involved in speech production.
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central nervous system
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The portion of the nervous system that includes the brain and the spinal cord.
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cerebellum
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A convoluted hindbrain structure involved in motor coordination and some aspects of learning and memory.
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cerebral cortex
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The gray, convoluted outer covering of the brain that is the seat of higher-order sensory, motor, perceptual, and mental processes.
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cerebrum
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The most advanced portion of the brain, containing the cerebral cortex and underlying structures.
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computerized axial tomography (CT or CAT) scan
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A method of scanning the brain with narrow beams of X rays that are then analyzed and combined by a computer to provide pictures of brain structures from many different angles.
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corpus callosum
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A broad band of white, myelinated fibers that connects the left and right cerebral hemispheres and allows the two hemispheres to communicate with one another.
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dendrites
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Small branching fibers that extend from the soma of a neuron and receive messages from adjacent neurons.
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electroencephalograph (EEG)
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A device used to record the simultaneous activity of many thousands of neurons through electrodes attached to the scalp.
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endocrine system
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The body’s system of glands that secrete hormones into the bloodstream and thereby affect many bodily functions.
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forebrain
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Brain structures above the midbrain, including the thalamus, hypothalamus, limbic system, and the cerebral hemispheres; involved in higher-order sensory, motor, and cognitive functions.
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functional MRI (fMRI)
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A brain-scanning procedure that produces pictures of blood flow in the brain taken less than a second apart.
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graded potentials
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A change in the electrical potential of a neuron that is proportional to the intensity of the incoming stimulation but not sufficient to produce an action potential.
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hindbrain
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The part of the brain situated immediately above the spinal cord that contains the brain stem and cerebellum.
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hippocampus
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A structure of the limbic system that plays a key role in the formation and storage of memories.
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homeostasis
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The maintenance of biological equilibrium, or balance, within the body.
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hormones
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Chemical substances secreted by the glands of the endocrine system that travel in the bloodstream and affect bodily organs, psychological functions, and development.
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hypothalamus
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A forebrain structure located below the thalamus and above the pituitary gland that controls autonomic and hormonal processes and plays a major role in many aspects of motivation and emotional behavior.
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interneurons
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Neurons that are neither sensory nor motor neurons but that perform associative or integrative functions within the nervous system.
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lateralization
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The degree of localization of a function in either the right or the left cerebral hemisphere.
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limbic system
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A group of subcortical structures, including the hippocampus and amygdala, that are involved in organizing many goal-directed and emotional behaviors.
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magnetic resonance imaging (MRI)
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A brainscanning procedure that produces a highly detailed image of living tissue based on the tissue’s response to a magnetic field; can be used to study both structure and, in the case of functional MRI (fMRI), brain functions as they occur.
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medulla
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A brain stem structure that controls vital functions, including heartbeat and respiration.
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midbrain
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Brain structures above the hindbrain that are involved in sensory and motor functions and in attention and states of consciousness.
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motor cortex
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The cortical area in the rear portion of the frontal lobes that controls voluntary movements on the opposite sides of the body.
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motor neurons
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Specialized neurons that carry neural messages from the brain and spinal cord to the muscles and glands.
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myelin sheath
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A fatty insulating substance on the axon of some neurons that increases the speed of neural transmission.
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neural plasticity
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The ability of neurons to modify their structure and function in response to experiential factors or injury.
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neural stem cells
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Immature “uncommitted” cells that can mature into any type of neuron or glial cell needed by the brain.
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neurogenesis
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The production of new neurons in the nervous system, sometimes to replace neurons that have died or been damaged.
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neuromodulators
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Neurotransmitter substances that are released by neurons and circulate within the nervous system to affect the sensitivity of many neurons to their natural transmitter substances.
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neurons
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Nerve cells that constitute the basic building blocks of the nervous system.
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neurotransmitters
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Chemical substances that are released from the axons of one neuron, travel across the synaptic space, and bind to specially keyed receptors in another neuron, where they produce a chemical reaction that is either excitatory or inhibitory.
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parasympathetic nervous system
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The branch of the autonomic nervous system that slows down bodily processes to conserve energy and reduce arousal.
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peripheral nervous system
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All of the neurons that connect the central nervous system with the sensory receptors, the muscles, and the glands.
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pons
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A brain stem structure having sensory and motor tracts whose functions are involved in sleep and dreaming.
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positron-emission tomography (PET) scan
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A procedure that provides a visual display of the absorption of a radioactive substance by neurons, indicating how actively they are involved as the brain performs a task.
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prefrontal cortex
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The area of the frontal lobe just behind the eyes and forehead that is involved in the executive functions of planning, self-awareness, and responsibility.
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psychoactive drugs
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Chemicals that produce alterations in consciousness, emotion, and behavior.
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receptor sites
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Protein molecules on neurons’ dendrites or soma that are specially shaped to accommodate a specific neurotransmitter molecule.
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resting potential
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The voltage differential between the inside and outside of a neuron (about −70 mv) caused by the unequal distribution of ions inside the neuron’s membrane and outside in the fluid surrounding the neuron when the neuron is at rest.
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reticular formation
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A structure extending from the hindbrain into the lower forebrain that plays a central role in consciousness, sleep, and attention, in part by alerting and activating higher brain centers (ascending portion) and by selectively blocking some inputs to higher regions in the brain (descending portion).
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reuptake
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The process whereby transmitter substances are taken back into the presynaptic neuron so that they do not continue to stimulate postsynaptic neurons.
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sensory neurons
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Specialized neurons that carry messages from the sense organs to the spinal cord and brain.
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somatic nervous system
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The branch of the peripheral nervous system that provides input from the sensory receptors and output to the voluntary muscles of the body.
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somatic sensory cortex
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Cortical strips in the front portions of the parietal lobes that receive sensory input from the opposite side of the body.
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sympathetic nervous system
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The branch of the autonomic nervous system that has an arousal function on the body’s internal organs, speeding up bodily processes and mobilizing the body.
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synaptic space
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The microscopic space between the axons of one neuron and the dendrites or cell body of another over which the nerve impulse is transmitted.
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synaptic vesicles
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Chambers within the axon that contain the neurotransmitter substance
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thalamus
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A major sensory integration and relay center in the forebrain, sometimes referred to as the brain’s sensory switchboard.
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Wernicke’s area
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An area of the left temporal lobe that is involved in speech comprehension.
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