BRS Spinal Cord

Question 1

the spinal cord extends to the level of L___ in newborns but will be at the level of L____ inadults

Answer 1

L3 in newborns

L1 in adults

Question 2

what are the borders of the spinomedullary junctions

Answer 2

foramen magnum
pyramidal decussation
emergence of first cervical nerve rootlets

Question 3

the first cervical nerve and the coccygeal nerve are unique in that

Answer 3

they contain no dorsal root (no sensory)

Question 4

meningeal ramus of the SC innervates

Answer 4

meninges and vertebral column

Question 5

the gray communicating rami contains what type of fibers

Answer 5

unmyelinated postganglionic sympathetic fibrers

Question 6

the ventral median fissure underlies what artery?

Answer 6

anterior spinal a

Question 7

lamina 1 is associated with what innevation

Answer 7

light touch
pain
temp

Question 8

what is lamina 2 known as

Answer 8

substantia gelatinosa
homologous to spinal trigeminal nucleus
light touch, pain, temp

Question 9

myotatic reflex

Answer 9

monosynaptic
afferent - muscle spindle and DRG of its 1a fiber
efferent - ventral horn motor neuron

Question 10

ascending pathways include

Answer 10

posterior column-medial lemniscus pathway 
anterolateral system 
lateral spinothalamic tract 
dorsal spinocerebellar tract 
ventral spinocerebellar tract 
cuneocerebellar tract

Question 11

the posterior column-medial lemniscus pathway conveys what information to the thalamus

Answer 11

tactile discrimination, vibration, proprioception

Question 12

the PCML pathway receives input from what type of receptors

Answer 12

pacini 
meissner corpuscles 
joint recpetors
muscle spindles 
golgi tendon organs

Question 13

the cell bodies for the first order neurons of the PCML pathway can be found where

Answer 13

dorsal root ganglia at all levels

Question 14

the first order neurons of the PCML pathway give rise to the fasciculus gracilis, originating from the _____ extremity and the fasciculus cuneatus, arising from the ______ extremity

Answer 14

gracilis = lower extremity 
cuneatus = upper extremity

Question 15

the cell bodies of the second order neurons in the PCML pathway are located within

Answer 15

the gracilis or cuneatus nuclei in the medulla

Question 16

after synapsing in the nuclei in the medulla, the PCML pathway continues on the _____ ______ fibers before decussating to form the _______ lemniscus

Answer 16

gracile and cuneate nuclei –> internal arcuate fibers –> decussate –> medial lemniscus

Question 17

the medial lemniscus carries proprioceptive input to the contralateral brainstem, terminating in the ____ of the thalamus

Answer 17

ventral posteriolateral nuclei

Question 18

third order neurons in the PCML pathway transverse the ______ _______ of the internal capsule to project to the somatosensory cortex

Answer 18

posterior limb of the internal capsule

Question 19

where do PCML fibers decussate

Answer 19

2nd order neurons from the gracile and cuneate nuclei cross the midline in the medulla

Question 20

the anterolateral system carries what kind of information

Answer 20

light touch from free nerve endings and merkel tactile discs

Question 21

the anterolateral system makes up what two tracts

Answer 21

ventral and lateral spinothalamic systems

Question 22

the spinothalamic system crosses the midline at the _____ ______ commissure to ascend to the contralateral ventral funiculus

Answer 22

anterior white commissure

Question 23

third order neurons of the spinothalamic system are found where in the thalamus

Answer 23

VPL nucleus of hte thalamus

Question 24

the lateral spinothalamic tract carries what type of sensory information

Answer 24

pain, itch, temperature

Question 25

what kind of receptors does the spinothalamic tract utilize

Answer 25

free nerve endings and thermal recpetors

Question 26

what type of fibers does the lateral spinothalamic tract utilize

Answer 26

alpha-gamma nad C fibers (fast and slow)

Question 27

first order neurons of the spinothalamic tract ascend in what tract

Answer 27

dorsolateral tract of lissauer –> ascend/descend 1-2 levels and synapse

Question 28

second order neuron cell bodies in the lateral spinothalamic tract are found where

Answer 28

in the dorsal horn

they go on to decussate in the anterior white commissure and ascend