Motor system Flashcards
What does ‘grade 0 power’ mean?
Complete paralysis
What does ‘grade 4 power’ mean?
Active movement against gravity and resistance
What does ‘grade 2 power’ mean?
Active movement with gravity eliminated
What does ‘grade 5 power’ mean?
Normal power
What does ‘grade 1 power’ mean?
Flicker or trace of contraction
What does ‘grade 3 power’ mean?
Active movement against gravity
What does ‘grade 0’ reflex mean?
Absent
What does ‘grade 2+’ reflex mean?
Normal
What does ‘grade 4+’ reflex mean?
Hyperactive with clonus
What does ‘grade 1+’ reflex mean?
Hypoactive
What does ‘grade 3+’ reflex mean?
Hyperactive without clonus
What is Henneman’s size principle?
Motor units are recruited incrementally, with progressively larger motor units recruited with more forceful movements
Which neurotransmitter and which receptor are involved in innervation of skeletal muscle?
ACh and nicotinic receptors
Why do we get fibrillations after a lower motor neurone injury?
There is upregulation of AChN receptors
What do muscle spindles sense?
Muscle stretch/length
What do Golgi tendon organs sense?
The amount of load/force on a muscle
What does decerebrate posturing imply?
Lesion below the level of the red nucleus
What does decorticate posturing imply?
Lesion above the level of the red nucleus
Describe decerebrate posturing
Extension of upper and lower limbs
Describe decorticate posturing
Flexion of upper limbs. Extension of lower limbs.
Why do the upper limbs flex in decorticate posturing?
The rubrospinal tract is intact and able to cause flexion of the upper limbs
Where is the pattern generator for locomotion?
Spinal cord
In the classical model of basal ganglia function, what is the function of the direct pathway?
Stimulate movement
In the classical model of basal ganglia function, what is the function of the indirect pathway?
Inhibit movement
