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80 Cards in this Set
- Front
- Back
General External Features of spinal cord
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w/in spinal (vertrbral) canal
from brain stem to conus-ap. L2 foramen mag. is division between brain and sp. cord. longitudinal view Flattened in dorsal |
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cervical enlargement
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origin for nerves supplying upper extremity
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lumbar enlargement
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origin for nerves supplying lower extremity
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conus medullaris
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cone shaped ending of sp. cord ap. T12-2
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filum terminal
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tissue from conus (pia mater) to coccyx
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causa equina
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"horses tail" group of spinal nerves inside spinal canal
(hangs off conus) |
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spinal segments
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there are 31; one pair of spinal nerves arises from each segment
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R & L sides of spinal cord
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anterior median fissure
posterior median sulcus |
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anterior median fissure
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a deep wide groove on the anterior side
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posterior median sulcus
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a shallow narrow furrous on the posterior dorsal side
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misnomer
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cord only appears segmented in early stages of development
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cross section of spinal cord
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lateral white column &
posterior white column |
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white matter
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surrounds gray matter; consists of myelinated fibers
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anterior(ventral) white column
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is column shaped in longitudinal view
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anterior white commissure
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pronounced "kom" is sure; connects white colimns
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Gray matter
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unmyelinated fibers & cell bodies (not myelinated); of multipolar neurons
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anterior(ventral) gray horn
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term "horn" is used when cord seen in x.s.
frontal division of the lateral ventricle of the brain, extending forward from Monro's interventricular foramen. |
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Lateral (gray) horn
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between the anterior & posterior gray horns
present only in the thoracic, upper lumbar, & sacral segments of spinal cord |
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Posterior (gray) horn
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contain somatic & autonomic sensory nuclei
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Gray commissure
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on either side (surrounds) central canal of sp. cord
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central canal of spinal cord
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continuous w/ ventricles (cavities) of brain; contains c.s.f. (cerebral spinal fluid)
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anterior median fissure
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deep, wide groove on the anterior(ventral)side groove penetrates whiter matter on spin. cord & divids the L&R side
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Posterior median sulcus
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shallower narrow furrow on the posterior dorsal side
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Tracts
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running inside the C.N.S.
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Ascending tracts
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is a sensory tract (consists of sensory or afferent neurons)
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Desending tracts
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is a motor tract (consists of motor or efferent neurons)
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Protective Coverings of spinal cord
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vertebral column
meninges |
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vertebral column
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strongest of the protective coverings
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vertebral (spinal) canal
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made up of indiv. vertebrae
stacked on top of one another |
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Meninges
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Cranial
Spinal |
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Cranial meninges
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conn. tissue encircle the brain
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spinal meninges
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conn. tissue surrounding spinal cord
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dura mater
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outer layer of meninges or outer meninx
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epidural space
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between dura & bone of vert. column
has fat, vessels it is the injection site for anesthetics |
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subdural space
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contains interstitial fluid
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Arachnoid
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middle layer of meninges or middle menix
(spiter webb like) |
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subarachnoid space
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contains c.s.f.
(below arachnoid memebrane) |
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Pia mater
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inner layer or inner menix (part of the meninges)
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Denticulate ligament
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runs laterally between tracts from pia to dura mater; helps to anchor chord in vertebral canal
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Meninges: 3 layers
protective cover: P A D |
Pia
Arachnoid Dura |
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Two major spinal cord functions
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connect periphery & brain
Intergrate reflexes |
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connect periphery & brain
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away from c.n.s. is periphery
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integrate reflexes
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volentary or involentary
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impulse conduction
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function is carried out by ascending & desending tracts; names of the tracts indicate the white column or funculus in which the tracts travel
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reflex
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a fast involuntary response to a change (stimulus) helps maintain homeostasis
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conduction pathway
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the path an impulse travels from it's origin to it's point of termination
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posterior or dorsal (sensory) root ganglion
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nerves outside c.n.s
ganglia contain unipolar neurons (swelling on back root) |
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anterior or ventral (motor) root
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contain axons of motor neurons, which conduct nerve impulses from the CNS to effector and cells.
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Reflex arc & conduction pathway
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involuntary conduction pathway
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receptor
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end of a dendrite either naked or associated w/ adjacent tissue
(picks up impulses all over body) |
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sensory neuron
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conducts impulse from recptors to c.n.s.
(travels through out) |
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center (brain and/or spinal cord)
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impulses translated, slowed, redirected
(can do anything) association neuron may or may not be present btwn. sensory and motor neurons |
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motor neuron
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carries impulse from c.n.s. to effector
(directly stimulated) |
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effector
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muscle or gland
(knee jerk reflex |
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spinal reflexes
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reflexes involving sp cord only
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somatic reflex
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reflexes inv. skeletal muscle
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cranial reflex
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reflexes inv. brain centers & cranial nerve
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visceral (autonomic) reflex
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reflex inv. involuntary effectors=smooth & cardiac muscles; glands
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cervial #
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C1-C8
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thoracic #
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T1-T12
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lumbar #
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L1-L5
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sacral #
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S1-S5
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coccygeal #
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1 PAIR
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sensory (afferent)
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to c.n.s.
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motor (efferent)
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away c.n.s.
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mixed neurons
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includes all spinal nerves & all directions
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epineurium
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surrounds entire nerve
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fascicles (fasciculi)
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bundle of nerve fibers (axons)
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perineurum
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surrounds or difines fascicles
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endoneurum
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surrounds each nerve fiber
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branches (rami) of a spin. nerve
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branches close to cord
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ramus
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means branch
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dorsal ramus
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sm. ramus of two
supplies deep muscle & skin of back of trunk |
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ventral ramus
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supplies superfical back muscles, all extremities
lateral & ventral trunk |
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rami communicants
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branches of sp. nerves
belongs to the a.n.s. |
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plexuses
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network of vessels, nerves, lymphatics, ect.
These spinal plexuses are formed from the venral rami of all sp. nerves except T2-T12 |
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dermatomes
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thin skin
skin segments somatic sensory & motor system are involved in the regulation of ________ |
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Plexuses
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Cervical
Brachial Lumbar Sacral |
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What nerves DO NOT form plexuses?
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intercostal (thoracic) nerves
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Posterior or dorsal (sensory) root
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contains only sensory axons, which skin, muscles and internal organs into CNS
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