Spinal cord: info to and from the brain

Question 1

What is ‘spinal white matter’?

Answer 1

Fibre tracts that carry information to and from the brain

Question 2

What are the 2 major descending limbs called?

Answer 2

Lateral descending system and Medial descending system

Question 3

Where are the fibres of the lateral system located and what do these influence?

Answer 3

Fibres of the lateral system are in the dorso-lateral part of the spinal cord, connect to motor neurones in lateral part of ventral horn.

This system influences lateral musculature

Question 4

Where are the fibres of the medial system located and what do these influence?

Answer 4

Fibres of the medial system are in the ventro-medial part and connect to motor neurones in the medial part of ventral horn.

This system influences medial musculature

Question 5

What are the 2 major ascending limbs called?

Answer 5

Dorsal column pathway and Spinothalamic tract (less sophisticated)

Question 6

What does the dorsal column pathway do?

Answer 6

Carries sensory info from joint and skin about: fine touch, vibration, two-point discrimination, proprioception from skin and joints

Question 7

What does the spinothalamic tract do?

Answer 7

Conveys crude touch (sense of being touched without knowledge of where), pain, temperature

Question 8

What are the 2 tracts of the lateral descending system and what do they do?

Answer 8

1) Corticospinal tracts - fibres strongly influence movement of every body part, in particular useful for individual finger use
2) Rubrospinal tract - can compensate almost completely for the loss of descending corticospinal input

Question 9

What are the 2 tracts of the medial descending system and what do they do?

Answer 9

1) Vestibulospinal tract - retains balance when body is moved (external disturbance)
2) Reticulospinal tract - helps retain posture and balance during our own volitational movements (internal disturbance)

Question 10

What do the medial systems control?

Answer 10

Posture and balance