11

Question 1

Dorsal root fibers enter spinal cord in how many bundles?

Answer 1

medial- Ia,Ib,AB—thick myelination

lateral- Asigma, C–

Question 2

What happens to most sensory fibers entering the spinal cord?

Answer 2

bifurcate–up or down

Question 3

reflex pathway must consist of how many neurons?

Answer 3

2- afferent=sensory reflexes right on LMN

efferent=motor

Question 4

Deep tendon reflex is what size of fiber?

Answer 4

Ia

Question 5

What does an exaggerated deep tendon reflex indicate?

Answer 5

lesion is on UPM because it disrupts inhibition on LMN

Question 6

What does a crossed extension reflex cause?

Answer 6

extension of opposite limb to prevent fall

Question 7

The withdrawal reflex uses what fiber size?

Answer 7

Asigma- crossing multiple segments

Question 8

What sensory system transmits tactile sensations, proprioception, and kinesthesia?

Answer 8

DCML

Question 9

The dorsal columns contain fibers from which side of the body?

Answer 9

same side—ipsilateral

Question 10

What does a highly refined somatotopic organization of dorsal columns provide?

Answer 10

spatial resolution

Question 11

In the dorsal columns are sacral or cervical fibers mor medial?

Answer 11

sacral

Question 12

Where do dorsal columns synapse?

Answer 12

medulla—>decussate—>medial lemniscus—>thalamus

Question 13

The medial lemniscus assumes what position as it ascentds into ventral posterolateral nucleus of thalamus?

Answer 13

dorsal-lateral

Question 14

Where is it recently believed for visceral pain to ascend?

Answer 14

dorsal column

Question 15

What do lesions of the dorsal column result in?

Answer 15

ipsilateral–loss of conscious proprioception, kinesthesia, 2pt discrimination, vibration sense
BELOW THE LESION LEVEL

Question 16

What about a lesion of the medial lemniscus?

Answer 16

all of the signs for dorsal column apply but to the contralateral side

Question 17

Simple test of DCML?

Answer 17

Romberg-without vision need conscious propioception

Question 18

What system relays pain, temperature, and crude touch?

Answer 18

spinothalamic

Question 19

Where does spinothalamic tract run?

Answer 19

anterior and lateral funiculi (anterolateral system)

Question 20

Where are fibers crossed in the spinothalamic tract?

Answer 20

cross in spinal cord in the ventral white commissure

Question 21

What do lesions of spinothalamic tract lead to?

Answer 21

loss of pain and temp on contralateral side of body below lesion

Question 22

Where does anesthesia begin in the spinothalamic tract?

Answer 22

1-2 segments below lesion—Asigma/C fibers ascend spinal cord in Lissauer’s Tract first before entering dorsal horn.

Question 23

Afferent pain and temp. end in what laminae?

Answer 23

I and II

Question 24

Crude touch end in what laminae?

Answer 24

I and V

Question 25

Sacral sparing?

Answer 25

lesions within the spinal cord effect cervical levels first due to organization of tracts with sacral levels on the outside

Question 26

What nucleus do most spinothalamic 1st order synapse on?

Answer 26

posteromarginal, substantia gelatinosa, nucleus proprius

Question 27

What does lesion of spinothalamic tract do?

Answer 27

loss of pain and temp on contralateral side below level of lesion ---maybe 1-2 segments below

Question 28

What does lesion of anterior white commisure lead to?

Answer 28

bilateral segmental loss of pain and temp

Question 29

What are the 3 major spinocerebellar pathways?

Answer 29

dorsal spinocerebellar tract cuneocerebellar tract ventral spinocerebellar tract

Question 30

What does the dorsal spinocerebellar tract convey?

Answer 30

information from muscle spindles and golgi tendon organs of LOWER LIMB/TRUNK to IPSILATERAL cerebellum

Question 31

Where does 2nd neuron begin in the dorsal spinoceerebellar tract?

Answer 31

dorsal nucleus of clarke

Question 32

What info does the cuneocerebellar tract carry>?

Answer 32

muscle spindles and tendon organs of UPPER LIMB to IPSILATERAL CEREBELLUM

Question 33

Where do neuron 1 axons follow for the cuneocerebellar tract?

Answer 33

fasciculus cuneatus

Question 34

Where are 2nd order neurons of the cuneocerebellar tract found?

Answer 34

accessory cuneate nucleus

Question 35

What info does ventral spinocerebellar tract carry?

Answer 35

nonconcisous proprioception about movement and posture to WHOLE LOWER LIMB rather than individual muscles

Question 36

Where does the ventral spinocerebellar tract cross the midline?

Answer 36

ventral white commissure at the level of the DRG and then ascend in contralateral ventral spinocerebellar tract

Question 37

Where does the ventral spinocerebellar tract cross back?

Answer 37

upper pons and enters cerebellum via superior cerebellar peduncle

Question 38

What is the largest descending spinal tract>?

Answer 38

corticospinal system

Question 39

Where do corticospinal fibers decussate?

Answer 39

90% in the pyramids to form lateral corticospinal tract

Question 40

Do the anterior corticospinal tracts decussate?

Answer 40

- yes eventually at the level of their corresponding 2nd order neuron - 2% don't- tract of barnes

Question 41

What are the UMN signs of lesions?

Answer 41

diminution of movement, increased spasticity, hyperreflexia, clonus, abnormal reflex, babinski sign

Question 42

What are the LMN signs of lesions?

Answer 42

Loss of movement, decrease muscle tone, hyporeflexia, fasciculations, atrophy

Question 43

Where does medial longitudinalfasciculus start and end?

Answer 43

MLF- pons/medulla not found below T7

Question 44

Where does the hypothalamospinal pathway begin and end?

Answer 44

hypothalamus to preganglionic SNA and paraSNA neurons in the spinal cord IML

Question 45

Damage to hypotalamospinal pathway above T1 causes?

Answer 45

Horner's syndrome

Question 46

What are important modulators of pain transmission?

Answer 46

descending bulbospinal pathways of the endogenous analgesia system---pons/medulla---descend in the raphespinal tract