8: Physiology - Spinal reflexes, upper motor neurons and the control of movement Flashcards Preview

Neurology Week 2 2018/19 > 8: Physiology - Spinal reflexes, upper motor neurons and the control of movement > Flashcards

Flashcards in 8: Physiology - Spinal reflexes, upper motor neurons and the control of movement Deck (12)
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1

Which type of neuron co-ordinates pairs of agonist/antagonist muscles to relax and contract in tandem to produce movement?

Excitatory and inhibitory interneurons

2

Which type of interneuron acts on

a) quadriceps femoris

b) biceps femoris

in the knee jerk reflex?

a) Excitatory interneuron, producing knee extension

b) Inhibitory interneuron, preventing knee flexion

3

What are the three simplified steps in motor movements?

1. Strategy - thought re: what you're out to do and the best way to do it

2. Tactics - sequence of muscle movements required to fulfill aim

3. Execution - activation of muscle groups to fulfill aims

4

Which parts of the CNS are responsible for

a) strategy

b) tactics

c) execution

of motor movements?

 

a) Neocortical areas (i.e areas outwith the motor cortex), basal ganglia

b) Motor cortex, cerebellum

c) Brainstem, spinal cord

5

What is the main motor pathway we need to know about?

Corticospinal tract

6

Where does the corticospinal tract start?

Pre-frontal gyrus i.e motor cortex

7

Where does the corticospinal tract decussate?

Pyramids of the medulla

85% of fibres swap sides

8

What is formed when 85% of motor fibres decussate at the pyramid of the medulla?

Lateral corticospinal tract

9

What is formed by the 15% of corticospinal tract fibres which DON'T decussate at the pyramids of the medulla?

Anterior corticospinal tract

still on the ipsilateral side

10

Which muscles are supplied by the

a) lateral corticospinal tract

b) anterior corticospinal tract?

a) Upper and lower limbs

b) Trunk (postural muscles)

11

When do anterior corticospinal tract fibres decussate?

At the spinal nerve levels of the muscles they supply

12

Which tracts, when allowed to excite muscles unopposed, cause

a) decorticate posturing

b) decerebrate posturing?

a) Rubrospinal tract

b) Reticulospinal tract