Lecture 16: Control of movement 1

Question 1

Are issues to do with lower motor neuron communication always to do with the neuron?

Answer 1

no e.g. myasthenia gravis generates antibodies which degrades postsynaptic receptors

Question 2

What is the role of the basal ganglia?

Answer 2

gating proper initiation of movement

Question 3

What is the role of the cerebellum?

Answer 3

sensory motor coordination of ongoing movement

Question 4

What is the role of the motor cortex?

Answer 4

planning, initiating, and directing voluntary movements

Question 5

What is the role of brainstem centers?

Answer 5

basic movements and postural control

Question 6

Where are motor neurons associated with distal muscles located in the spinal cord?

Answer 6

lateral in the spinal cord

Question 7

Where are motor neurons associated with proximal muscles located in the spinal cord?

Answer 7

medial in the spinal cord

Question 8

What is a motor unit?

Answer 8

the collection of muscle fibers innervated by a motor neuron

Question 9

Why are muscle fibers of the same motor unit spread out?

Answer 9

so that forces are evenly distributed -> prevents muscles from ripping themselves apart

Question 10

What do motor neurons receive input from?

Answer 10

input from spinal interneurons, muscle spindles and upper motor neurons in the brain

Question 11

What are intrafusal muscle fibers?

Answer 11

specialised stretch receptors

Question 12

What happens in the stretch reflex circuit when liquid is added to a glass held in the hand?

Answer 12

length change in muscle fiber -> activation of spindle receptor -> increase in spindle afferent discharge -> increased activation of alpha motor neuron -> increases force required to hold glass

Question 13

How are golgi tendon organs able to detect force?

Answer 13

located in muscle tendons

Question 14

What are neurons of golgi tendon organs always connected to?

Answer 14

inhibitory interneurons