Spinal Cord

Question 1

What gives rise to the cauda equina?

Answer 1

Conus Medularis.

Question 2

In the brain, the grey matter cortex is on the outside, is the spinal cord the same or different?

Answer 2

In the spinal cord the central area has the grey processing matter.

The rest is white matter, and there is a vast amount

Question 3

What is the posterior median sulcus?

Answer 3

Halfway point for the spinal cord.

Question 4

Difference between post. and ventral median sulcus?

Answer 4

Ventral Median Sulcus has a significant rift, whereas the Dorsal is tightly packed

Question 5

Where do the dorsal roots come in?

Answer 5

The Dorsolateral sulcus.

Question 6

What are white matter ‘funniculi’?

Answer 6

larges white matter tracts/ropes. Make up ~50% of the spinal cord. There is a ventral, lateral and dorsal funiculus

Question 7

Dorsal funiculus —>
ventral funiculus —>
lateral funiculus —>

Answer 7

Dorsal funiculus —> sensation
ventral funiculus —> pain + temp
lateral funiculus —> motor

Question 8

What are the 2 subdivisions of the Dorsal Funiculus

Answer 8

Gracile fasiculus

Cuneate fasiculus

Question 9

Purpose of the Gracile Funiculus?

Answer 9

Carries all the sensory info from the leg/foot as it comes in from the dorsal root ganglion to a part of the gracile fasiculus.
Brought in froma Psuedo unipolar neuron (unyelinated).

Question 10

Sensory Info from my toe would go where in the gracile funiculus?

Answer 10

Medial most part, wheres hip would be lateral.

Organised like a homonculus.

Question 11

The gracile fuciculus is present at ___ levels of the spinal cord. Why?

Answer 11

All levels, as it takes info from the Lower Limbs

Question 12

The cuneate fusiculus is present at ___ levels of the spinal cord. Why?

Answer 12

As it carries sensory info from the upper limbs, and therefor will not be present further down.

Question 13

Why does injury your foot hurt more then injuring your knee?

Answer 13

There are more nerves present in the foot (see pg 45)

Question 14

What’s in grey matter

Answer 14

Dorsal Horn
Ventral Horn
Lateral Horn

Question 15

What’s in white matter

Answer 15

Columns
tracts
Fasiculi
Funiculi

Question 16

Cell that can pick up information about pain and temperature come through the ‘Tract of Lissauer’. Where do they synapse

Answer 16

Rexas Lamine

Synapse at Lamina 1 or 2, where the 2nd order neurons then decussate to the ventral funinculus and travel up to the thalamus via the spinothalamic tract

Question 17

Describe Lamina 1 fibres

Answer 17

Slow Conducting
Un-myelinated
Convey info on pain and temp

Question 18

Convergence of the spinal cord.

Answer 18

Occurs on lamina 3/4 and allows the huge surface area of the body to be condensed into the spinal cord, means that many fibres that come into the lamina also synapse onto the funniculus —> brain

Question 19

Lamina 2

Answer 19

• Pain and temp

- Aren’t really affected by anasthetic, except opiod analgesics (as they have opiod receptors)

Question 20

Lamina 3 + 4

Answer 20

• Convergence of touch and pressure sensory neurons
• Nucleus proprios
• These neurons then still travel to their respective areas of the gracile and cuneate fasiculus

Question 21

Lamina 5 + 6

Answer 21

Info on noxious visceral stimuli

Question 22

Lamina 7

Answer 22

All involved in ANS

Centrally: “Dorsal Nucleus of Clark” which is involved in the cerebellum tract and unconscious proprioreception

Question 23

Lamina 8+9

Answer 23

where Lower motor neurons pass through (from previously synapsing with UMNs in the lateral funinculus) where they then pass out via the ventral root > muscles of the body

Extensors: periphery
Flexors: medially

Question 24

What type of cells does each lamina have? Remember granule=sensory and pyramidal=motor

Answer 24

L1-4: granule
L5-7: mixed
L8-9: pyramidal

Question 25

Where does Pain and temp info from L1/2 go?

Answer 25

To the OPPOSING Ventral Funiculus, then up to the brain via the ‘spinothalamic tract’

Question 26

Where does the info from Lamina 3/4 go?

Answer 26

To the dorsal columns upto the spinal cord on the SAME SIDE

Question 27

What passes through lamina 8/9 and then where does it go?

Answer 27

UMN from the lateral funiculus (from the motor cortex) come in, synapsing with LMN at 8/9 to travel to the the body via the ventral root

Question 28

Myotactic Reflex

Answer 28

Happens bc the discriminative ifor from the periphery, instead of going to the gracile/cuneate fasiculi, it comes down to 8/9 and informs them, the flexor/extensor neurons coordinate for movement such as walking.

Brain only informed AFTER

Question 29

Withdrawal Reflex

Answer 29

Due to pain or heat, also occurs at the spinal segmental level.
Info synapses in 1/2, and then from there another fibre comes down to 8/9, then ANOTHER fibre that comes down through ventral roots.

Theese 3 fibres cause us to pull away before the brain even realises