{"id":2146,"date":"2014-10-30T04:47:31","date_gmt":"2014-10-30T04:47:31","guid":{"rendered":"https:\/\/courses.candelalearning.com\/apvccs\/?post_type=chapter&p=2146"},"modified":"2019-07-14T19:44:38","modified_gmt":"2019-07-14T19:44:38","slug":"glossary-the-nervous-system","status":"web-only","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/suny-dutchess-anatomy-physiology\/chapter\/glossary-the-nervous-system\/","title":{"raw":"Glossary: The Nervous System","rendered":"Glossary: The Nervous System"},"content":{"raw":"astrocyte:<\/strong> glial cell type of the CNS that provides support for neurons and maintains the blood-brain barrier\r\n\r\nautonomic nervous system (ANS):<\/strong> functional division of the nervous system that is responsible for homeostatic reflexes that coordinate control of cardiac and smooth muscle, as well as glandular tissue\r\n\r\naxon:<\/strong>\u00a0single process of the neuron that carries an electrical signal (action potential) away from the cell body toward a target cell<\/span>\r\n\r\naxon hillock:<\/strong> tapering of the neuron cell body that gives rise to the axon\r\n\r\naxon segment:<\/strong> single stretch of the axon insulated by myelin and bounded by nodes of Ranvier at either end (except for the first, which is after the initial segment, and the last, which is followed by the axon terminal)\r\n\r\naxon terminal:<\/strong> end of the axon, where there are usually several branches extending toward the target cell\r\n\r\naxoplasm:<\/strong> cytoplasm of an axon, which is different in composition than the cytoplasm of the neuronal cell body\r\n\r\nbiogenic amine:<\/strong> class of neurotransmitters that are enzymatically derived from amino acids but no longer contain a carboxyl group\r\n\r\nbipolar:<\/strong> shape of a neuron with two processes extending from the neuron cell body\u2014the axon and one dendrite\r\n\r\nblood-brain barrier (BBB):<\/strong> physiological barrier between the circulatory system and the central nervous system that establishes a privileged blood supply, restricting the flow of substances into the CNS\r\n\r\nbrain:<\/strong> the large organ of the central nervous system composed of white and gray matter, contained within the cranium and continuous with the spinal cord\r\n\r\ncell body<\/strong>: area of a neuron that contains the nucleus and most organelles\r\n\r\ncentral nervous system (CNS):<\/strong> anatomical division of the nervous system located within the cranial and vertebral cavities, namely the brain and spinal cord\r\n\r\nchemical synapse:<\/strong> connection between two neurons, or between a neuron and its target, where a neurotransmitter diffuses across a very short distance\r\n\r\ncholinergic system:<\/strong> neurotransmitter system of acetylcholine, which includes its receptors and the enzyme acetylcholinesterase\r\n\r\ndendrite:<\/strong> one of many branchlike processes that extends from the neuron cell body and functions as a contact for incoming signals (synapses) from other neurons or sensory cells\r\n\r\ndepolarization:\u00a0<\/strong>change in a cell membrane potential that causes it to become more positive in charge\r\n\r\nelectrical synapse:<\/strong> connection between two neurons, or any two electrically active cells, where ions flow directly through channels spanning their adjacent cell membranes\r\n\r\nenteric nervous system (ENS):<\/strong> neural tissue associated with the digestive system that is responsible for nervous control through autonomic connections\r\n\r\nependymal cell:<\/strong> glial cell type in the CNS responsible for producing cerebrospinal fluid\r\n\r\nganglion:<\/strong> localized collection of neuron cell bodies in the peripheral nervous system\r\n\r\nglial cell:<\/strong> one of the various types of neural tissue cells responsible for maintenance of the tissue, and largely responsible for supporting neurons\r\n\r\ngray matter:<\/strong> regions of the nervous system containing cell bodies of neurons with few or no myelinated axons; actually may be more pink or tan in color, but called gray in contrast to white matter\r\n\r\ninitial segment:<\/strong> first part of the axon as it emerges from the axon hillock, where the electrical signals known as action potentials are generated\r\n\r\nintegration:<\/strong> nervous system function that combines sensory perceptions and higher cognitive functions (memories, learning, emotion, etc.) to produce a response\r\n\r\nionotropic receptor:<\/strong> neurotransmitter receptor that acts as an ion channel gate, and opens by the binding of the neurotransmitter\r\n\r\nleakage channel:<\/strong> ion channel that opens randomly and is not gated to a specific event, also known as a non-gated channel\r\n\r\nligand-gated channels:<\/strong> another name for an ionotropic receptor for which a neurotransmitter is the ligand\r\n\r\nlower motor neuron:<\/strong> second neuron in the motor command pathway that is directly connected to the skeletal muscle\r\n\r\nmechanically gated channel:<\/strong> ion channel that opens when a physical event directly affects the structure of the protein\r\n\r\nmetabotropic receptor:<\/strong> neurotransmitter receptor that involves a complex of proteins that cause metabolic changes in a cell\r\n\r\nmicroglia:<\/strong> glial cell type in the CNS that serves as the resident component of the immune system\r\n\r\nmultipolar:<\/strong> shape of a neuron that has multiple processes\u2014the axon and two or more dendrites\r\n\r\nmuscarinic receptor:<\/strong> type of acetylcholine receptor protein that is characterized by also binding to muscarine and is a metabotropic receptor\r\n\r\nmyelin sheath:<\/strong> lipid-rich layer of insulation that surrounds an axon, formed by oligodendrocytes in the CNS and Schwann cells in the PNS; facilitates the transmission of electrical signals\r\n\r\nmyelin:<\/strong> lipid-rich insulating substance surrounding the axons of many neurons, allowing for faster transmission of electrical signals\r\n\r\nnerve:<\/strong> cord-like bundle of axons located in the peripheral nervous system that transmits sensory input and response output to and from the central nervous system\r\n\r\nneuron:<\/strong> neural tissue cell that is primarily responsible for generating and propagating electrical signals into, within, and out of the nervous system\r\n\r\nneuropeptide:<\/strong> neurotransmitter type that includes protein molecules and shorter chains of amino acids\r\n\r\nneurotransmitter:<\/strong> chemical signal that is released from the synaptic end bulb of a neuron to cause a change in the target cell\r\n\r\nnicotinic receptor:<\/strong> type of acetylcholine receptor protein that is characterized by also binding to nicotine and is an ionotropic receptor\r\n\r\nnode of Ranvier:<\/strong> gap between two myelinated regions of an axon, allowing for strengthening of the electrical signal as it propagates down the axon\r\n\r\nnucleus:<\/strong> in the nervous system, a localized collection of neuron cell bodies that are functionally related; a \u201ccenter\u201d of neural function\r\n\r\noligodendrocyte:<\/strong> glial cell type in the CNS that provides the myelin insulation for axons in tracts\r\n\r\nperipheral nervous system (PNS):<\/strong> anatomical division of the nervous system that is largely outside the cranial and vertebral cavities, namely all parts except the brain and spinal cord\r\n\r\nprocess:<\/strong> in cells, an extension of a cell body; in the case of neurons, this includes the axon and dendrites\r\n\r\nSchwann cell:<\/strong> glial cell type in the PNS that provides the myelin insulation for axons in nerves\r\n\r\nsatellite cell:<\/strong> glial cell type in the PNS that provides support for neurons in the ganglia\r\n\r\nsoma:<\/strong> in neurons, that portion of the cell that contains the nucleus; the cell body, as opposed to the cell processes (axons and dendrites)\r\n\r\nsomatic nervous system (SNS):<\/strong> functional division of the nervous system that is concerned with conscious perception, voluntary movement, and skeletal muscle reflexes\r\n\r\nspinal cord:<\/strong> organ of the central nervous system found within the vertebral cavity and connected with the periphery through spinal nerves; mediates reflex behaviors\r\n\r\nstimulus:<\/strong> an event in the external or internal environment that registers as activity in a sensory neuron\r\n\r\nsynapse:<\/strong> narrow junction across which a chemical signal passes from neuron to the next, initiating a new electrical signal in the target cell\r\n\r\nsynaptic cleft:<\/strong> small gap between cells in a chemical synapse where neurotransmitter diffuses from the presynaptic element to the postsynaptic element\r\n\r\nsynaptic end bulb:<\/strong> swelling at the end of an axon where neurotransmitter molecules are released onto a target cell across a synapse\r\n\r\ntract:<\/strong> bundle of axons in the central nervous system having the same function and point of origin\r\n\r\nunipolar:<\/strong> shape of a neuron which has only one process that includes both the axon and dendrite\r\n\r\nvoltage-gated channel:<\/strong> ion channel that opens because of a change in the charge distributed across the membrane where it is located\r\n\r\nwhite matter:<\/strong> regions of the nervous system containing mostly myelinated axons, making the tissue appear white because of the high lipid content of myelin","rendered":"

astrocyte:<\/strong> glial cell type of the CNS that provides support for neurons and maintains the blood-brain barrier<\/p>\n

autonomic nervous system (ANS):<\/strong> functional division of the nervous system that is responsible for homeostatic reflexes that coordinate control of cardiac and smooth muscle, as well as glandular tissue<\/p>\n

axon:<\/strong>\u00a0single process of the neuron that carries an electrical signal (action potential) away from the cell body toward a target cell<\/span><\/p>\n

axon hillock:<\/strong> tapering of the neuron cell body that gives rise to the axon<\/p>\n

axon segment:<\/strong> single stretch of the axon insulated by myelin and bounded by nodes of Ranvier at either end (except for the first, which is after the initial segment, and the last, which is followed by the axon terminal)<\/p>\n

axon terminal:<\/strong> end of the axon, where there are usually several branches extending toward the target cell<\/p>\n

axoplasm:<\/strong> cytoplasm of an axon, which is different in composition than the cytoplasm of the neuronal cell body<\/p>\n

biogenic amine:<\/strong> class of neurotransmitters that are enzymatically derived from amino acids but no longer contain a carboxyl group<\/p>\n

bipolar:<\/strong> shape of a neuron with two processes extending from the neuron cell body\u2014the axon and one dendrite<\/p>\n

blood-brain barrier (BBB):<\/strong> physiological barrier between the circulatory system and the central nervous system that establishes a privileged blood supply, restricting the flow of substances into the CNS<\/p>\n

brain:<\/strong> the large organ of the central nervous system composed of white and gray matter, contained within the cranium and continuous with the spinal cord<\/p>\n

cell body<\/strong>: area of a neuron that contains the nucleus and most organelles<\/p>\n

central nervous system (CNS):<\/strong> anatomical division of the nervous system located within the cranial and vertebral cavities, namely the brain and spinal cord<\/p>\n

chemical synapse:<\/strong> connection between two neurons, or between a neuron and its target, where a neurotransmitter diffuses across a very short distance<\/p>\n

cholinergic system:<\/strong> neurotransmitter system of acetylcholine, which includes its receptors and the enzyme acetylcholinesterase<\/p>\n

dendrite:<\/strong> one of many branchlike processes that extends from the neuron cell body and functions as a contact for incoming signals (synapses) from other neurons or sensory cells<\/p>\n

depolarization:\u00a0<\/strong>change in a cell membrane potential that causes it to become more positive in charge<\/p>\n

electrical synapse:<\/strong> connection between two neurons, or any two electrically active cells, where ions flow directly through channels spanning their adjacent cell membranes<\/p>\n

enteric nervous system (ENS):<\/strong> neural tissue associated with the digestive system that is responsible for nervous control through autonomic connections<\/p>\n

ependymal cell:<\/strong> glial cell type in the CNS responsible for producing cerebrospinal fluid<\/p>\n

ganglion:<\/strong> localized collection of neuron cell bodies in the peripheral nervous system<\/p>\n

glial cell:<\/strong> one of the various types of neural tissue cells responsible for maintenance of the tissue, and largely responsible for supporting neurons<\/p>\n

gray matter:<\/strong> regions of the nervous system containing cell bodies of neurons with few or no myelinated axons; actually may be more pink or tan in color, but called gray in contrast to white matter<\/p>\n

initial segment:<\/strong> first part of the axon as it emerges from the axon hillock, where the electrical signals known as action potentials are generated<\/p>\n

integration:<\/strong> nervous system function that combines sensory perceptions and higher cognitive functions (memories, learning, emotion, etc.) to produce a response<\/p>\n

ionotropic receptor:<\/strong> neurotransmitter receptor that acts as an ion channel gate, and opens by the binding of the neurotransmitter<\/p>\n

leakage channel:<\/strong> ion channel that opens randomly and is not gated to a specific event, also known as a non-gated channel<\/p>\n

ligand-gated channels:<\/strong> another name for an ionotropic receptor for which a neurotransmitter is the ligand<\/p>\n

lower motor neuron:<\/strong> second neuron in the motor command pathway that is directly connected to the skeletal muscle<\/p>\n

mechanically gated channel:<\/strong> ion channel that opens when a physical event directly affects the structure of the protein<\/p>\n

metabotropic receptor:<\/strong> neurotransmitter receptor that involves a complex of proteins that cause metabolic changes in a cell<\/p>\n

microglia:<\/strong> glial cell type in the CNS that serves as the resident component of the immune system<\/p>\n

multipolar:<\/strong> shape of a neuron that has multiple processes\u2014the axon and two or more dendrites<\/p>\n

muscarinic receptor:<\/strong> type of acetylcholine receptor protein that is characterized by also binding to muscarine and is a metabotropic receptor<\/p>\n

myelin sheath:<\/strong> lipid-rich layer of insulation that surrounds an axon, formed by oligodendrocytes in the CNS and Schwann cells in the PNS; facilitates the transmission of electrical signals<\/p>\n

myelin:<\/strong> lipid-rich insulating substance surrounding the axons of many neurons, allowing for faster transmission of electrical signals<\/p>\n

nerve:<\/strong> cord-like bundle of axons located in the peripheral nervous system that transmits sensory input and response output to and from the central nervous system<\/p>\n

neuron:<\/strong> neural tissue cell that is primarily responsible for generating and propagating electrical signals into, within, and out of the nervous system<\/p>\n

neuropeptide:<\/strong> neurotransmitter type that includes protein molecules and shorter chains of amino acids<\/p>\n

neurotransmitter:<\/strong> chemical signal that is released from the synaptic end bulb of a neuron to cause a change in the target cell<\/p>\n

nicotinic receptor:<\/strong> type of acetylcholine receptor protein that is characterized by also binding to nicotine and is an ionotropic receptor<\/p>\n

node of Ranvier:<\/strong> gap between two myelinated regions of an axon, allowing for strengthening of the electrical signal as it propagates down the axon<\/p>\n

nucleus:<\/strong> in the nervous system, a localized collection of neuron cell bodies that are functionally related; a \u201ccenter\u201d of neural function<\/p>\n

oligodendrocyte:<\/strong> glial cell type in the CNS that provides the myelin insulation for axons in tracts<\/p>\n

peripheral nervous system (PNS):<\/strong> anatomical division of the nervous system that is largely outside the cranial and vertebral cavities, namely all parts except the brain and spinal cord<\/p>\n

process:<\/strong> in cells, an extension of a cell body; in the case of neurons, this includes the axon and dendrites<\/p>\n

Schwann cell:<\/strong> glial cell type in the PNS that provides the myelin insulation for axons in nerves<\/p>\n

satellite cell:<\/strong> glial cell type in the PNS that provides support for neurons in the ganglia<\/p>\n

soma:<\/strong> in neurons, that portion of the cell that contains the nucleus; the cell body, as opposed to the cell processes (axons and dendrites)<\/p>\n

somatic nervous system (SNS):<\/strong> functional division of the nervous system that is concerned with conscious perception, voluntary movement, and skeletal muscle reflexes<\/p>\n

spinal cord:<\/strong> organ of the central nervous system found within the vertebral cavity and connected with the periphery through spinal nerves; mediates reflex behaviors<\/p>\n

stimulus:<\/strong> an event in the external or internal environment that registers as activity in a sensory neuron<\/p>\n

synapse:<\/strong> narrow junction across which a chemical signal passes from neuron to the next, initiating a new electrical signal in the target cell<\/p>\n

synaptic cleft:<\/strong> small gap between cells in a chemical synapse where neurotransmitter diffuses from the presynaptic element to the postsynaptic element<\/p>\n

synaptic end bulb:<\/strong> swelling at the end of an axon where neurotransmitter molecules are released onto a target cell across a synapse<\/p>\n

tract:<\/strong> bundle of axons in the central nervous system having the same function and point of origin<\/p>\n

unipolar:<\/strong> shape of a neuron which has only one process that includes both the axon and dendrite<\/p>\n

voltage-gated channel:<\/strong> ion channel that opens because of a change in the charge distributed across the membrane where it is located<\/p>\n

white matter:<\/strong> regions of the nervous system containing mostly myelinated axons, making the tissue appear white because of the high lipid content of myelin<\/p>\n\n\t\t\t

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