The ascending tracts

Question 1

What sort of information is transmitted in ascending tracts?

Answer 1

sensory information

Question 2

What is another name for ascending tracts?

Answer 2

somatosensory pathways

Question 3

What are the two types of ascending tracts?

Answer 3

• Conscious tracts: comprised of dorsal column-medial lemniscal pathway and the anterolateral system
• Unconscious tracts: comprised of spinocerebellar tracts

Question 4

What sort of sensory information is carried by the dorsal column-medial lemniscal pathway (DCML)?

Answer 4

touch, vibration and proprioception

Question 5

What are the 3 groups of neurones involved in this pathway?

Answer 5

first, second and third order

Question 6

What does the first order neurones do in DCML?

Answer 6

sensory info regarding touch, proprioception or vibration from peripheral nerves to medulla oblongata. Signals from the upper (t6 and above) to nucleus cuneatus and from lower (bellow T6) limbs to nucleus gracilis of medulla oblongata.

Question 7

What does the second order neurones do in DCML?

What happens to the fibres in the medulla oblongata?

Answer 7

transfer from cuneate nucleus or gracilis to thalamus.

The fibres decussate.

Question 8

What does the third order neurones do in DCML?

Answer 8

carry info from thalamus to ipsilateral primary sensory cortex of the brain.

Question 9

What are the two tracts in the anterolateral system? what sensory information? How many groups of neurones are there in the anterolateral system?

Answer 9

• Anterior spinothalamic tract: sensory of crude touch and pressure.
• Lateral spinothalamic tract: sensory of pain and temperature.

Question 10

What are the two tracts in the anterolateral system? what sensory information? How many groups of neurones are there in the anterolateral system?

Answer 10

• Anterior spinothalamic tract: sensory of crude touch and pressure.
• Lateral spinothalamic tract: sensory of pain and temperature.

Question 11

First order neurones on anterolateral system?

Answer 11

sensory receptors in periphery to substantia gelatinosa.

Question 12

Second order neurones in anterolateral system?

Answer 12

carry sensory information from substantia gelatinosa to thalamus via 2 distinct tracts:

1) Crude touch and pressure fibres - enter in anterior spinothalamic tract
2) pain and temperature fibres- enter in lateral spinothalamic tract.

Both run alongside each other

Question 13

third order neurones in anterolateral system

Answer 13

sensory info from thalamus to ipsilateral primary sensory cortex of the brain.

Question 14

What are spinocerebellar tracts?

Answer 14

tracts that carry unconscious proprioceptive infromation.

Question 15

what can be seen in someone with damage to DCML pathway?

Answer 15

Ipsilateral loss of touch, vibration and proprioception

Question 16

what can be seen in someone with damage to anterolateral pathway?

Answer 16

contralateral loss of pain and temperature.

Question 17

Damage to spinocerebellar tract?

Answer 17

ipsilateral loss of muscle co-ordination