Session 5 - Motor System Flashcards
Where are the cell bodies of upper motor neurones found?
Motor cortex
Where are the cell bodies of lower motor neurones found?
Ventral horn or brainstem nuclei
Which type of motor neurone could possibly be damaged by a CNS or PNS lesion?
Lower motor neurone
What do the CN III nuclei contain?
The cell bodies of lower motor neurones which run through the oculomotor nerve.
What is a muscle spindle?
A receptor in skeletal muscle that detects stretch
Describe the patella reflex.
?
What is reciprocal inhibition in relation to the the knee jerk reflex?
When the quadriceps contracts, the hamstrings relax so as not to counteract the movement.
What is the physiological role of deep tendon reflexes?
Postural reflexes, help us to maintain equilibrium
What is the normal response in the Babinski reflex?
Flexion of the big toe
What are the signs of lower motor neurone damage?
Weakness Areflexia Muscle wasting Fasciculation Hypotonia
Why does muscle wasting occur in lower motor neurone damage?
Lower motor neurones supply trophic factors to the muscle. Destroying the lower motor neurones interrupts the transfer of growth factors to the muscle, resulting in muscle wasting.
Are motor neurones found in the basal ganglia or cerebellum?
No, only found in the motor cortex.
What two effects can upper motor neurones have on lower motor neurones?
Excitatory effect Inhibitory effect (via inhibitory interneurones)
What is the net effect of upper motor neurones on lower motor neurones?
Inhibitory
