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S&F- Chapter 8- Nerv
ous System Terms
Term | Definition |
---|---|
acetylcholine | chemical neurotransmitter |
anesthesia | loss of sensation |
arachnoid mater | delicate, weblike middle membrane covering the brain, the meninges |
astrocyte | a glial cell |
axon | nerve cell process that transmits impulses away from the cell body |
catecholamines | norepinephrine and epinephrine |
dendrite | branching or treelike; a nerve cell process that transmits impulses toward the body |
dopamine | chemical neurotransmitter |
dura mater | literally "strong or hard mother"; outermost layer of the meninges |
effector | responding organ; for example, voluntary and involuntary muscle, the heart, and glands |
endorphin | chemical in central nervous system that influences pain perception; a natural painkiller |
enkephalins | peptide chemical in the central nervous system that acts as a natural painkiller |
fight-or-flight response | the changes produced by increased sympathetic impulses allowing the body to deal with any type of stress |
ganglia | a region of gray (unmyelinated) nerve tissue (usually this term is only used for gray matter regions in the PNS) |
ganglion | a group of nerve cell bodies located in the PNS |
glia | supporting cells of nervous tissue; also called neuroglia |
hydrocephalus | abnormal accumulation of cerebrospinal fluid; "water on the brain" |
interneuron | nerves that conduct impulses from sensory neurons to motor neurons |
limbic system | a collection of various small regions of the brain that act together to produce emotion and emotional response; sometimes called "the emotional brain" |
meninges | fluid-containing membranes surrounding the brain and spinal cord |
microglia | one type of connective tissue found in the brain and spinal cord |
motor neuron | transmits impulses from the brain and spinal cord to muscles and glandular epithelial tissues |
multiple sclerosis | the most common primary disease of the central nervous system; a myelin disorder |
myelin | lipoid substance found in the myelin sheath around some nerve fibers |
neuron | nerve cell, including its processes (axons and dendrites) |
neurotransmitter | chemical by which neurons communicate |
nodes of Ranvier | indentations that are found between adjacent Schwann cells |
norepinephrine | hormone secreted by adrenal medulla; released by sympathetic nervous system |
oligodendrocyte | a cell that holds nerve fibers together and produces the myelin sheath around axons in the central nervous system |
parasympathetic nervous system (PNS) | part of the autonomic nervous system; ganglia are connected to the brainstem and the sacral segments of the spinal cord; controls many visceral effectors under normal conditions |
pia mater | the vascular innermost covering (meninx) of the brain and spinal cord |
postganglionic neurons | autonomic neurons that conduct nerve impulses from a ganglion to cardiac or smooth muscle or glandular epithelial tissue |
postsynaptic neuron | a neuron situated distal to a synapse |
preganglionic neurons | autonomic neurons that conduct nerve impulses between the spinal cord and a ganglion |
presynaptic neuron | a neuron situated proximal to a synapse |
receptor | peripheral beginning of a sensory neuron's dendrite |
relfex arc | allows an impulse to travel in only one direction |
saltatory conduction | when a nerve impulse encounters myelin and "jumps" from one node of Ranvier to the next |
sensory neurons | neurons that transmit impulses to the spinal cord and brain from all parts of the body |
serotonin | a neurotransmitter that belongs to a group of compounds called catecholamines |
sympathetic nervous system | part of the autonomic nervous system; ganglia are connected to the thoracic and lumbar regions of the spinal cord; functions as an emergency system |
synapse | junction between adjacent neurons |
synaptic cleft | the space between a synaptic knob and the plasma membrane of a postsynaptic neuron |
tract | bundles of axons in the CNS |