Spinal Chord

Question 1

What 2 types of multipolar neurons found in gray matter of spinal cord?

Answer 1

Golgi type 1

Golgi type 2

Question 2

Distinguish golgi type 1 and golgi type 2 neurons.

Answer 2

Golgi type 1 - long axons, found mostly in anterior gray horns, form long tracts of spinal cord

Golgi type 2 - short axons, found mostly in posterior gray horns

Question 3

Which nuclei of the posterior gray horn are found in all spinal cord segments?

Answer 3

Marginal nucleus
Substantia Gelatinosa of Rolando
Chief sensory nucleus/ Nucleus proprius

Question 4

The dorsal nucleus of Clarke is found in which spinal segments?

Answer 4

C8 - L3

Question 5

The intermediolateral nucleus are found in which spinal segments?

Answer 5

T1-L2

Question 6

Name the nuclei found in the anterior gray horn.

Answer 6

Anterior motor neurons
Gamma motor neurons
Renshaw cells

Question 7

State the neuron in the anterior gray horn that goes to the 1) Intrafusal muscle fibers 2) Extrafusal muscle fibers

Answer 7

*MNEMONIC: AEGI
Anterior motor neurons –> Extrafusal
Gamma motor neurons –> Infrafusal

Question 8

Role of Renshaw cells

Answer 8

Inhibitory neurons

Question 9

Differentiate association tracts from commissural tracts.

Answer 9

Association tracts (intrinsic tracts) connect different segments of the spinal cord that are adjacent. Commissural tracts connect same segment but opposite halves

Question 10

Second order neurons form ascending tracts except in which part of the spinal cord?

Answer 10

The posterior white funiculus which is formed by 1st order neurons (for dorsal lemniscal pathway)

Question 11

Location of 3rd order neurons

Answer 11

subcortical areas of brain

Question 12

The 3 stages following complete transection of spinal cord.

Answer 12

1. Shock/Flaccidity
2. Reflex activity
3. Reflex failure

Question 13

How long does the spinal shock stage last in humans?

Answer 13

3 weeks

Question 14

Paraplegia is…

Answer 14

paralysis of lower limbs

Question 15

Events of the stage of spinal shock/flaccidity.

Answer 15

Muscles become flaccid
Paralysis of all limbs (quadriplegia) or lower limbs (paraplegia)
Decrease in heart rate to become thready
Paralysis of respiratory muscles = arrest of breathing
Complete sensory loss in parts below level of damage due to damage to posterior root ganglia
Effect on blood pressure depends on if lesion is below L2 or at/above T1

Question 16

Which tracts carry pain and temperature?

Answer 16

Fasciculus dorsolateralis

Lateral spinothalamic tract

Question 17

Which tract carries subconscious kinesthetic sensation? Which one carries conscious kinesthetic sensation?

Answer 17

Subconscious kinesthetic sensation - Lateral and ventral spinocerebellar tracts
Conscious - Dorsal Column

Question 18

Differences between Reflex activity stage of Complete transection and Incomplete transection

Answer 18

Complete transection

• tone returns to flexors first (paraplegia in flexion)
• reflexes return to flexors first
• Babinski reflex first to return
• mass reflex occurs

Incomplete transection

• tone returns to flexors first (paraplegia in extension)
• reflexes return to extors first (Elicit Philipson reflex)
• no mass reflex

Question 19

What is Mass reflex

Answer 19

when skin of lower limbs or lower abdominal wall is scratched and ellicits spasms of lower limb flexors, sweating, and urination

Question 20

Describe Philipson reflex and give another name for it

Answer 20

Clasp-knife reflex in which limb offers resistance to flexion, but when forced to flex, the resistance is abolished immediately and the limb suddenly flexes

Question 21

Events of Reflex failure stage following spinal cord transection.

Answer 21

1. Mass reflex abolished
2. Harder to ellicit reflex; reflex requires higher threshold stimuli
3. Muscle atrophy

Question 22

Differentiate Brown-sequard syndrome from incomplete transection.

Answer 22

In brown-sequard, the entire one half of the spinal cord is affected/lesioned. But in incomplete transection, a section of spinal cord is lesioned at one point.

Question 23

Effects on the same side as the lesion, below level of lesion in Spinal cord hemisection (Brown sequard syndrome) .

Answer 23

Sensory changes on the same side; loss of
-fine touch/tactile
-vibration
-2-point discrimination
-conscious kinesthetic sensation
(uncrossed fibers of dorsal column pathway in spinal cord)
-pain and temperature (from uncrossed fasciculus dorsolateralis tract)

Motor changes

• hypertonicity (UMN no longer inhibiting motor neurons making them hyperactive)
• spasticitiy
• deep reflexes exaggerated, superficial reflexes lost
• +ve Babinski
• decrease in blood pressure

Question 24

Which spinal cord segments are mostly affected by Syringomelia?

Answer 24

Lower cervical

Upper thoracic

Question 25

Describe symptoms of Syringomelia if it

a) remains around central canal
b) extends to posterior gray horn
c) extends to anterior gray horn
d) extends to white matter

Answer 25

It if remains around central canal
-loss of temperature, pain, and crude touch because fibers decussating across anterior gray commissure are affected

If extends to posterior gray horn (loss of all sensation since this is where all the sensory nuclei are )

If extends to anterior gray horn (flaccid paralysis because some motor fibers decussate across)

If it extends to white matter (symptoms similar to UMN lesions; spastic paralysis, winging of scapula, scoliosis)