Motor Systems

Question 1

The most important tract for voluntary movement

Answer 1

Corticospinal tract

Question 2

How many synapses are in the corticospinal tract

Answer 2

1 with the motor neurone - monosynaptic

Question 3

Type of fibers the motor neurones in the corticospinal tract have

Answer 3

alpha (alpha motor neurones)

Question 4

The main structures involved in the course of the corticospinal tract

Answer 4

originates in motor cortex
internal capsule
crus cerebri (midbrain)
pons
forms pyramidal tract at base of medulla
(most) decussate
lateral corticospinal tract 

(some fibers travel down the ventral corticospinal tract the decussate)

Question 5

the corticospinal tract synapses in which part of the spinal cord

Answer 5

ventral horn

Question 6

Where does the rubrospinal tract originate?

Answer 6

red nucleus in the midbrain

Question 7

Where does the rubrospinal tract decussate?

Answer 7

(almost immediately) in the pons

Question 8

Where does the rubrospinal tract travel in the spinal cord?

Answer 8

lateral column

Question 9

Neurotransmitter and receptor at neuromuscular junctions

Answer 9

Ach

nicotinic Ach receptors

Question 10

Flexor muscle

Answer 10

contraction bends limb

Question 11

Extensor muscle

Answer 11

contraction straightens limb

Question 12

Ventromedial (“extrapyramidal”) pathways include

Answer 12

tectospinal tract
vestibulospinal
pontine & medullary reticulospinal tracts

Question 13

What controls spinal motorneuron activity

Answer 13

local feedback via dorsal roots from sensory input
spinal inhibitory interneurones

(together these are reflexes)

Question 14

Receptors activated in the flexor (withdrawal) reflex

Answer 14

Adelta nociceptors

Question 15

Tectospinal tract originates

Answer 15

superior colliculus - midbrain

Question 16

Vestibulospinal tract originates

Answer 16

vestiblar nuclei - medulla

Question 17

Tectospinal tract neurones decussate where

Answer 17

midbrain, almost immediately leaving the superior colliculus

Question 18

Pontine reticulospinal tract function

Answer 18

Enhances anti-gravity reflexes (faciliates extensors to maintain standing position in stretch reflex)

Question 19

Medullary reticulospinal tract function

Answer 19

Frees anti-gravity muscles from a reflex (allows voluntary override)

Question 20

Tectospinal tract function

Answer 20

Receives visual input from visual cortex & creates a map of the world around us

Question 21

Vetsibulospinal tract function

Answer 21

Facilitates extensor muscles for upright, balanced posture

Controls neck & back muscles for head movement