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85 Cards in this Set
- Front
- Back
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the spinal cord develops from the _______ portion of the embryonic _______ tube
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the spinal cord develops from the CAUDAL portion of the embryonic NEURAL tube
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ebryonic development
alar plate (dorsal half) will become... |
interneurons
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ebryonic development
basal plate (ventral half) will become... |
lower motor neurons
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neural crest cells form from these (and they are future sensory neurons)
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dorsal root ganglia
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the spinal cord is ___ cm in length and __ cm in diameter
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40-45 cm in length
2 cm in diameter |
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spinal cord starts and ends at...
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start at foramen magnum and end in L1--L2
(nerve roots come down to L5) |
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most common reasons to perform a lumbar puncture:
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1- rule out meningitis
2- sample CSF or measure it's pressure 3- inject Ab or medications |
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spinal cord protected by
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bone, meninges and CSF
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space between vertebrae and the dural sheath; filled with fat and a network of veins
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epidural space
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part of the spinal cord filled with CSF
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arachnoid mater
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fibrous extension that anchors the spinal cord to the coccyx
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filum terminale
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end of the solid part of the spinal cord (cone-shaped)
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conus medullaris
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delicate shelves of pia mater, attach spinal cord to the vertebrae
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denticulate ligaments
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continuous with 4th ventricle
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central canal
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31 paris attach to the cord, paired by roots (dorsal & ventral)
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spinal nerves
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site where nerves serving the UPPER limbs emerge
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cervical enlargements
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site where nerves serving the LOWER limbs emerge
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lumber enlargements
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collection of nerve roots at inferior end of vertebral canal
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cauda equina
"horse's tail" |
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disk herniation that can kill; always ask about recent bowel and bladder habits
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cauda equina syndrome
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run the length of the spinal cord and divide it into right and left halves
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ventral median fissure
dorsal median sulcus (<-- this is more shallow) |
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consists of cell bodies, unmyelinated processes & neuroglia
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gray matter
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encloses the central canal
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gray commissure
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spinal roots-
consists entirely of interneurons; SENSORY info processed here |
Posterior (dorsal) horn
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spinal roots-
interneurons and somatic lower MOTOR neurons |
anterior (ventral) horns
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contain sympathetic nerve cell bodies
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Lateral horns
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these spinal roots are only in T1-L2 segments of the spinal cord
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lateral horns
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gray matter organization-
Dorsal half |
sensory roots &
ganglia |
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gray matter organization-
Ventral half |
motor roots
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the 4 zones of gray matter
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somatic sensory (SS)
visceral sensory (VS) somatic motor (SM) visceral motor (VM) |
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the 4 zones of gray matter
autonomics- needs to go to smooth and cardiac muscle |
visceral motor (VM)
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the 4 zones of gray matter-
voluntary motor info that runs to skeletal muscle |
Somatic motor (SM)
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white matter fibers run in these three direx AND are responsible for
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ascending (sensory)
descending (motor) transverse (either) |
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each funiculus contains...
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several fiber tracts (axons)
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white matter- pathway generalizations
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pathways are paired
most decussate (cross) most consist of 2-3 neurons most exhibit somatotopy |
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cell bodies reside in dorsal root ganglia (DRG)
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1st order neurons
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cell bodies reside in dorsal horn of spinal cord OR in the brainstem
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2nd order neurons
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cell bodies reside in the thalamus
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3rd order neurons
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transmit somatosensory cortex of cerebrum
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3rd order neurons
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3 ascending (sensory) pathways:
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spinothalamic
dorsal columns spinocerebellar |
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2 descending (motor) pathways:
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pyramidal
extrapyramidal |
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ascending pathways-
pain, temperature, crude touch, deep pressure |
spinothalamic
(anterolateral) |
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ascending pathways-
fine touch, conscious propioception, pressure, vibration |
dorsal (white) columns
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ascending pathways-
unconscious propioception |
spinocerebellar tracts
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ascending pathways-
these two pathways are specific |
dorsal (white) columns
spinocerbellar |
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ascending pathways-
this pathway is nonspecific |
spinothalamic
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ascending pathways-
decussates in spinal cord |
spinothalamic
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ascending pathways-
decussates in medulla oblongata |
dorsal (white) columns
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ascending pathways-
lower extremity tract |
fasciculus gracilis
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ascending pathways-
upper extremity tract |
fasciculus cuneatus
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ascending pathways-
does not decussate |
spinocerebellar tract
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doesn't have a 3rd order
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spinocerebellar tracts
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consist of polymodal neurons and are activated by several types of stimulus
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nonspecific ascending pathways
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these pathways are important in alertness & arousal
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nonspecific
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these ascending pathways carry info about a single type of stimulus
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specific
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2 types of descending motor pathways
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1- Direct (Pyramidal)
2- Indirect (Extrapyramidal) |
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where do upper motor neurons arise?
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precentral gyrus (motor cortex)
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where do lower motor neurons arise?
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anterior (ventral) horn
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the part of the direct pathway that innervates cranial nerve nuclei
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Corticobulbar
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this pathway regulates fine, skilled, voluntary movements
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direct pathway
(pyramidal) |
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direct pathways originate with the pyramidal neurons in the _________
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precentral gyri
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this pathway includes the brain stem, motor nuclei and all motor pathways not part of the pyramidal system
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Indirect (Extrapyramidal) system
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The 4 extrapyramidal (multineuronal) pathways/TRACTS
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reticulospinal tracts
rubrospinal tracts tectospinal tracts vetibulospinal tracts |
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these motor pathways are complex and multisynaptic
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Indirect (Extrapyramidal) system
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extrapyramidal tracts-
maintain balance and posture |
reticulospinal tract
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extrapyramidal tracts-
large muscle movement |
rubrospinal tract
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extrapyramidal tracts-
mediate head and eye mvmts response to visual stimuli |
tectospinal tract
(with superior colliculi) |
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extrapyramidal tracts-
controls correct position of head and neck |
vestibulospinal tracts
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lower motor neurons are damaged; severe damage to ventral root or anterior horn cells; no voluntary or involuntary control of muscles
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flaccid paralysis
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upper motor neurons of the primary motor cortex are damaged; no voluntary control of muscles
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spastic paralysis
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cross sectioning of the spinal cord results in motor and sensory loss in regions ) ________ to the lesion
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inferior
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transection between T1 and L1
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paraplegia
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transection in the cervical region
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quadriplegia
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clinical term for "paresthesia"
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neuropraxia
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tingling, prickling, numbness on skin surface
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paresthesia
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posturing-
elbows flexed, indicating damage to coritcospinal tract |
Decorticate
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posturing-
elbows extended & hands pronated, indicating damage to coritcospinal tract |
Decerebrate
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posturing-
VERY severe; damage to brainstem or cerebellum |
Decerebrate
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destruction of the anterior horn motor neurons by the poliovirus
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poliomyelitis
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symptoms- fever, headache, muscle pain/weakness, loss of somatic reflexes
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Poliomyelitis
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neuromuscular condition involving destruction of anterior horn motor neurons and fibers of the PYRAMIDAL tract
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Lou Gehrig's disease
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loss of the ability to speak, swallow and breath
death occurs within 5 years |
Lou Gehrig's disease
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linked to malfunctioning genes for glutamate transporter and/or superoxide dismutase
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Lou Gehrig's disease
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spastic paralysis & HYPERactive reflexes are symptoms of what type of lesion?
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upper motor neuron lesion (UMNL)
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lesions-
contractions of a muscle following a sudden stretch is what type of lesion? |
upper motor neuron lesion (UMNL)
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lesions-
symptoms include flaccid paralysis, atrophy, HYPOactive reflexes & fasciculations (muscle twitching) |
lower motor neuron lesion (LMNL)
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