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56 Cards in this Set
- Front
- Back
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In adults where does the spinal cord begin?
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Foramen magnum
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The SC ends where in adults?
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conus medullaris at L1-2
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How many spinal cord segments are there?
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31
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T OR F Motor nerves leave the SC thru the posterior roots?
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False--leave thru anterior roots
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T or F Sensory nerves leave the SC thru the posterior roots?
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True
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What's another name for sensory nerves?
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afferent
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What's another name for motor nerves?
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efferent
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Why is gray matter gray?
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Axons are unmyelinated
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Are posterior & anterior horns found in all SC segments?
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Yes
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T or F Lateral horns are found only in L 1-5?
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False--found only in T1-2 & L1-2
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What type(s) of neurons are found in the SC?
A. interneurons B. sensory relay C. anterior motor D. all of the above |
D. all of the above
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Anterior motor neurons have how many neurons in each section:
A. several billion B. several million C. several thousand |
C. Several thousand
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Anterior motor neurons leave the cord via the _______ root & innervate _________
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anterior(ventral) horn and innervate skeletal muscle fibers
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Name the 2 types of motor neurons
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Alpha & gamma
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T or F Alpha motor nerves < gamma in size?
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False--alpha larger
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Do extrafusal nerves in skeletal muscle shorten during contraction & generate tension?
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Yes
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How much of the total motor neuron pool do alpha motor neurons make up?
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2/3 alpha
1/3 gamma |
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Where are alpha & gamma motor neurons located?
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Anterior (ventral) horn
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What type of motor neurons innervate intrafusal fibers in muscle spindles?
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A-gamma axons
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Do motorneurons receive input from sensory neurons?
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Yes
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Where is most of motor neuron input derived from?
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interneurons
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Are interneurons present in all gray matter?
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Yes
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Which statements about interneurons are FALSE:
A. The most numerous cells in gray matter B. Can only act as excitatory C. Have extensive interconnections D. Synapse with alpha motor neurons |
B. Can act as both excitatory & inhibitory
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T or F Interneurons only receive input from motor neurons?
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False--receive input from certain sensory nerves also
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T or F Most info directed to alpha motor neurons is delivered via interneurons?
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True
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T or F White matter nerve tracts contain cell bodies?
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False
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The ______ spinothalamic tract and ______ spinothalamic tract are examples of white matter ascending nerve tracts.
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lateral & posterior
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The principle pathway for transmission of pain & temp sensation in WM is the:
A. lateral spinothalamic tracts B. posterior spinothalamic tracts |
A. lateral spinothalamic
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The principle pathway for transmission of tactile & proprioceptive sensation in WM is the:
A. lateral spinothalamic tracts B. posterior spinothalamic tracts |
B. posterior spinothalamic
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Define proprioceptive sensations:
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Position of limb in relation to space
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White matter is myelinated or unmyelinated?
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Myelinated
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The dura mater terminates at what level?
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S2
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The epidural space extends from _____ to ______?
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foramen magnum to sacral hiatus
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The epidural space contains
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fat, CT & venous plexuses
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The SC receives its blood supply from which 3 vessels:
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vertebral arteries, thoracic aorta, abdominal aorta
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Characteristics of anterior spinal artery:
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single midline vessel
supplies anterior 2/3 of SC originates from vertebral arteries at skull base |
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Characteristics of posterior spinal arteries:
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paired vessels
supply posterior 1/3 of SC arise from posterior inferior cerebellar arteries |
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Radicular arteries suppy blood to:
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anterior & posterior spinal arteries
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What's another name for artery of adamkiewicz?
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arteria radicularis magna
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Characteristics of artery of adamkiewicz:
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single branch of aorta
almost always arises on L side origin T9-12 in 60 % pop supplies nearly all blood flow to lower thoracic & lumbar cord SC ischemia may result from injury to artery --> paragplegia |
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Injury to which artery may result in SC ischemia & paraplegia?
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artery of adamkiewicz (arteria radicularis magna)
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Spinal nerves are formed by
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joining of anterior & posterior roots at each spinal cord segment
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At what area do the spinal nerves exit the vertebral column?
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intervertebral foramina
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There are 31 pairs of spinal nerves:
__ cervical __ thoracic __ lumbar __ sacral __ coccygeal |
8 cervical
12 thoracic 5 lumbar 5 sacral 1 coccygeal |
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Define dermatome
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Region of skin supplied by a specific spinal segment
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Spinal nerves are MIXED nerves, meaning that they contain:
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somatic sensory & motor and autonomic nerve fibers
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The 2 major branches (rami) of the spinal nerves are
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anterior ramus & posterior ramus
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The major portion of spinal nerves is the anterior or posterior ramus?
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Posterior
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Which ramus division supplies the long muscles of the back & the tissue overlying them?
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Posterior primary division
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Define nerve plexus
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intermingling collection of nerves that emanate from different cord segments
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What's the purpose of nerve plexuses?
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Provide nerve consolidation
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Does a plexus typically contain both sensory & motor nerve fibers?
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Yes
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The cervical plexus includes which nerves:
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anterior rami of C1-C4
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The diaphragm is innervated by
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phrenic nerve C3-C5
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The brachial plexus includes which nerves
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anterior rami of C5-C8 & T1
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The lumbosacral plexus includes which nerves
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anterior rami of L1-L5 & S1-S4
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