Neuro - Sensorimotor Pathways

Question 1

Where does the medial lemniscus pathway decussate?

Answer 1

In the medulla oblongata, with the internal arcuate fibres

Question 2

Describe the path of fine touch and proprioception sensation from the upper limb

Answer 2

Receptors
Cell bodies are in the dorsal root ganglion
Travel up spinal cord in cuneate fasiculus of the dorsal column
Synapse in cuneate nucleus of medulla oblongata
Decussate in medulla oblongata, in internal arcuate fibres
Synapse in thalamus, in ventral posterolateral nucleus
Fibres go on to the post central gyrus

Question 3

Describe the path of fine touch and proprioception sensation from the lower limb

Answer 3

Receptors
Cell bodies are in the dorsal root ganglion
Travel up spinal cord in gracile fasiculus of the dorsal column
Synapse in gracile nucleus of medulla oblongata
Decussate in medulla oblongata, in internal arcuate fibres
Synapse in thalamus, in ventral posterolateral nucleus
Fibres go on to the post central gyrus

Question 4

Which pathway carries fine touch and proprioception from the limbs?

Answer 4

The medial lemniscus pathway

Question 5

Which pathway carries limb motor?

Answer 5

The lateral corticospinal tract

Question 6

Which spinal tract carries pain and temperature?

Answer 6

The lateral spinothalamic

Question 7

Which spinal tract carries crude touch?

Answer 7

The anterior spinothalamic tract

Question 8

Which spinal tract carries axial motor?

Answer 8

The ventral corticospinal

Question 9

What components make up the dorsal column?

Answer 9

The gracile and cuneate fasiculi

Question 10

Which pathway carries limb motor?

Answer 10

The lateral corticospinal tract

Question 11

Which spinal tract carries pain and temperature?

Answer 11

The lateral spinothalamic

Question 12

Which spinal tract carries crude touch?

Answer 12

The anterior spinothalamic tract

Question 13

Which spinal tract carries axial motor?

Answer 13

The ventral corticospinal

Question 14

What components make up the dorsal column?

Answer 14

The gracile and cuneate fasiculi

Question 15

Where does the pathway carrying axial motor decussate?

Answer 15

In the anterior white commissure of the vertebral level it will innervate

Question 16

Where does the pathway carrying limb motor decussate?

Answer 16

In the medulla oblongata

Question 17

Describe the corticospinal pathway

Answer 17

Begins in the Pre-central gyrus, in the Primary motor cortex
Fibres travel through the internal capsule
In the medulla, 70-90% of the fibres decussate and travel down the lateral corticospinal tract - these supply the limbs.
The rest of the fibres descend through the anterior corticospinal tract until their vertebral level, where they decussate.
Both then synapse in the ventral horn before exiting the spinal cord.

Question 18

Describe the path of the spinothalamic pathway

Answer 18

Receptor
Sensory neurone
Dorsal root ganglion
Enters the spinal cord and travels up or down 1 or 2 vertebral levels within Lissauer’s fasiculus before synapsing on the dorsal horn
Decussates immediately in the anterior white commissure then travels up in the spinothalamic tract
Synapse in the thalamus before carrying on to the post-central gyrus