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56 Cards in this Set

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  • Back
In adults where does the spinal cord begin?
Foramen magnum
The SC ends where in adults?
conus medullaris at L1-2
How many spinal cord segments are there?
31
T OR F Motor nerves leave the SC thru the posterior roots?
False--leave thru anterior roots
T or F Sensory nerves leave the SC thru the posterior roots?
True
What's another name for sensory nerves?
afferent
What's another name for motor nerves?
efferent
Why is gray matter gray?
Axons are unmyelinated
Are posterior & anterior horns found in all SC segments?
Yes
T or F Lateral horns are found only in L 1-5?
False--found only in T1-2 & L1-2
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
Anterior motor neurons have how many neurons in each section:

A. several billion
B. several million
C. several thousand
C. Several thousand
Anterior motor neurons leave the cord via the _______ root & innervate _________
anterior(ventral) horn and innervate skeletal muscle fibers
Name the 2 types of motor neurons
Alpha & gamma
T or F Alpha motor nerves < gamma in size?
False--alpha larger
Do extrafusal nerves in skeletal muscle shorten during contraction & generate tension?
Yes
How much of the total motor neuron pool do alpha motor neurons make up?
2/3 alpha
1/3 gamma
Where are alpha & gamma motor neurons located?
Anterior (ventral) horn
What type of motor neurons innervate intrafusal fibers in muscle spindles?
A-gamma axons
Do motorneurons receive input from sensory neurons?
Yes
Where is most of motor neuron input derived from?
interneurons
Are interneurons present in all gray matter?
Yes
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
T or F Interneurons only receive input from motor neurons?
False--receive input from certain sensory nerves also
T or F Most info directed to alpha motor neurons is delivered via interneurons?
True
T or F White matter nerve tracts contain cell bodies?
False
The ______ spinothalamic tract and ______ spinothalamic tract are examples of white matter ascending nerve tracts.
lateral & posterior
The principle pathway for transmission of pain & temp sensation in WM is the:

A. lateral spinothalamic tracts
B. posterior spinothalamic tracts
A. lateral spinothalamic
The principle pathway for transmission of tactile & proprioceptive sensation in WM is the:


A. lateral spinothalamic tracts
B. posterior spinothalamic tracts
B. posterior spinothalamic
Define proprioceptive sensations:
Position of limb in relation to space
White matter is myelinated or unmyelinated?
Myelinated
The dura mater terminates at what level?
S2
The epidural space extends from _____ to ______?
foramen magnum to sacral hiatus
The epidural space contains
fat, CT & venous plexuses
The SC receives its blood supply from which 3 vessels:
vertebral arteries, thoracic aorta, abdominal aorta
Characteristics of anterior spinal artery:
single midline vessel
supplies anterior 2/3 of SC
originates from vertebral arteries at skull base
Characteristics of posterior spinal arteries:
paired vessels
supply posterior 1/3 of SC
arise from posterior inferior cerebellar arteries
Radicular arteries suppy blood to:
anterior & posterior spinal arteries
What's another name for artery of adamkiewicz?
arteria radicularis magna
Characteristics of artery of adamkiewicz:
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
Injury to which artery may result in SC ischemia & paraplegia?
artery of adamkiewicz (arteria radicularis magna)
Spinal nerves are formed by
joining of anterior & posterior roots at each spinal cord segment
At what area do the spinal nerves exit the vertebral column?
intervertebral foramina
There are 31 pairs of spinal nerves:

__ cervical
__ thoracic
__ lumbar
__ sacral
__ coccygeal
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
Define dermatome
Region of skin supplied by a specific spinal segment
Spinal nerves are MIXED nerves, meaning that they contain:
somatic sensory & motor and autonomic nerve fibers
The 2 major branches (rami) of the spinal nerves are
anterior ramus & posterior ramus
The major portion of spinal nerves is the anterior or posterior ramus?
Posterior
Which ramus division supplies the long muscles of the back & the tissue overlying them?
Posterior primary division
Define nerve plexus
intermingling collection of nerves that emanate from different cord segments
What's the purpose of nerve plexuses?
Provide nerve consolidation
Does a plexus typically contain both sensory & motor nerve fibers?
Yes
The cervical plexus includes which nerves:
anterior rami of C1-C4
The diaphragm is innervated by
phrenic nerve C3-C5
The brachial plexus includes which nerves
anterior rami of C5-C8 & T1
The lumbosacral plexus includes which nerves
anterior rami of L1-L5 & S1-S4