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70 terms

nervous system

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neuron
a nerve cell; an electrically excitable cell specialized for producing and transmitting action potentials and secreting chemicals that stimulate adjacent cells
afferent neuron
carries action potentials to the CNS
efferent neuron
carries action potentials away from the CNS
central nervous system
consists of the brain and spinal cord.
peripheral nervous system
consists of all nerves and and ganglia; all of the nervous system except the brain and spinal cord
gray matter
where the neuron cell bodies, dendrites, and synapses are found
white matter
white myelinated nervous tissue
somatic nervous system
a division of the nervous system that includes efferent fibers mainly from the skin, muscles, and skeleton and afferent fibers to the skeletal muscles
autonomic nervous system
a motor division of the nervous system that innervates glands, smooth muscle, and cardiac muscle; consists of sympathetic and parasympathetic divisions and functions largely without voluntary control
cranial nerves
any of the 12 pairs of nerves connected to the base of the brain and passing through the foramina of the cranium
spinal nerves
any of the 31 pairs of nerves that arise from the spinal cord and pass through the intervertebral foramina
sympathetic nervous system
a division of the autonomic nervous system that issues efferent fibers through the thoracic and lumbar nerves and usually exerts adrenergic effects on its target organs; includes a chain of paravertebral ganglia adjacent to the vertebral column, and the adrenal medulla
prosencephalon
develops into the forebrain and thalamus
mesencephalon
develops into the midbrain
metencephalon
develops into the hindbrain along with the myelincephelon
myelincephalon
deleops into the hindbrain along with the metencephalon
rhombincephalon
develops into the cerebellum and medulla oblongata
axon
a process of a neuron that transmits action potentials; also called a nerve fiber. There is only one axon to a neuron and it is usually much longer and less branched than the dendrites.
soma
the cell body of a neuron
perikaryon
another word for the cell body of a neuron
axon hillock
the mound on the side of the soma from where the axon originates
axon collateral
a branch of an axon
axon terminal
the end of the axon; has synaptic knobs that synapse with other cells
telodendria
an extensive complex of fine branches at the end of an axon; also called the terminal aborization
dendrites
processes of a neuron that receive information from other cells or environmental stimuli and conduct signals to the soma. Dendrites are usually shorter, more branched, and more numerous than the axon and are incapable of producing action potentials
Schwann cell
cells that envelop nerve fibers in the PNS. They produce a myelin sheath, and they also assist in the regeneration of damaged fibers
myelin
a lipid sheath around a nerve fiber, formed from closely spaced spiral layers of the plasma membrane of a Schwann cell or oligodendrocyte
Node of Ranvier
the space between Schwann cells that can conduct action potentials
neurilemma
the outermost coil of a Schwann cell, external to the myelin sheath
axolemma
the cell membrane of an axon
axoplasm
the cytoplasm of an axon
neuroglia
all cells of nervous tissue except neurons; cells that perform various supportive and protective roles for the neurons
oligodendrocyte
a type of glial cell that wraps around nerve fibers in the CNS and produces a myelin sheath around them
astrocyte
star shaped glial cells that form scar tissue to replace damaged nervous tissue
microglia
small macrophages that develop from monocytes, they phagocytize dead nervous tissue, microorganisms, and foreign matter. They concentrate in areas damaged by infection, trauma or stroke.
ganglion
a cluster of nerve cell bodies in the PNS
basal nuclei
deep masses of cerebral gray matter that play a role in the coordination of posture and movement
projection tract
a bundle of axons that communicates between two or more regions of the brain
association tract
a bundle of axons that communicates between subregions of the same area of the brain; from "primary" areas to "association" areas
ependyma
produce cerebrospinal fluid and line the cavities of brain and spinal cord
proprioception
the nonvisual perception, usually subconscious, of the position and movements of the body, resulting from input from proprioceptors and the vestibular apparatus
association neuron
a neuron that transmits action potentials from efferent neurons to afferent neurons
synapse
the junction between the synaptic knob of one neuron and some other part of another cell
action potential
a rapid voltage change in which a plasma membrane briefly reverses electrical polarity; has a self-propagating effect that produces a traveling wave of excitation in nerve and muscle cells
neurotransmitter
a chemical released at the distal end of an axon that stimulates an adjacent cell
lateral geniculate nucleus
relays visual information from the optic tracts to the visual cortex
medial geniculate nucleus
relays auditory information from the inferior colliculi to the auditory cortex
substancia nigra
is a primary producer of dopamine
superior colliculi
regulate reflexes of eyes and head to visual stimuli, and receives information from inferior colliculi about auditory stimuli
inferior colliculi
receives all info from the inner ear about sound, relays this info to the thalamus; also regulates reflexive movements of the head and trunk to auditory stimuli
olivary nucleus
relays info to and from the inner ear and to and from the cerebellum
nucleus gracilis
receives general sensory info from the lower half of the body
nucleus cuneatus
receives general sensory info from the upper half of the body
path of cerebrospinal fluid from the lateral ventricle to the superior sagittal blood sinus
lateral ventricle - interventricular foramen of Monro - 3rd ventricle - cerebral aqueduct of sylvius - 4th ventricle - foramina of Luschka OR foramen of Magendie - subarachnoid space - arachnoid villus - superior sagittal blood sinus
choroid plexus
made up of pia mater, nonciliated ependyma, capillaries. Secretes cerebrospinal fluid.
4 sources of blood supply to the brain
2 vertebral arteries and 2 internal carotids
parietal lobe
sensory reception
temporal lobe
hearing, smell, learning, memory, emotional behavior, visual recognition
limbic system
emotion and memory
frontal lobe
voluntary motor functions, personality, mood, emotion, judgment, aggression
pyramidal tracts
originates in the precentral gyrus, extends from the primary motor cortex down through the interal capsule, through the midbrain and the pons, into the medulla (where the decussate), and extending through the spinal cord as the corticospinal tracts
pairs of cervical spinal nerves
8
pairs of thoracic spinal nerves
12
pairs of lumbar spinal nerves
5
pairs of sacral spinal nerves
5
pairs of coccygeal spinal nerves
1
fasciculus gracilis
relays general sensory info from the lower half of the body to the nucleus gracilis
fasciculus cuneatus
relays general sensory info from the upper half of the body to the nucleus cuneatus
sympathetic nervous system
thoracolumbar subdivison
parasympathetic nervous system
craniosacral subdivision