PSC1002/L21 Sensation & Motor Control I Flashcards
Give the 2 steps of sensory input.
Sensory transduction
Action potential initiation
Which kind of axons are for proprioception?
Ia/Ib
Aa
Which kind of axons are cutaneous mechanoreceptors?
II
AB
Which kind of axons are for temperature and pain? (2)
III & IV
Ad & C
What is microneurography?
Properties of receptors studied by recording action potentials from single afferent nerves and mapping ‘receptive fields’ (set of stimuli that evoke a response)
What is the difference between tonic and phasic responses?
Tonic - slowly adapting
Phasic - rapidly adapting
What is the function of extrafusal fibres and alpha motor units?
Generate force
What is the function of intrafusal muscle fibres and gamma motor units?
Set gain of spindle response
What divides extrafusal and intrafusal muscle fibres?
A collagen/fibroblast sheath with a ‘fusiform’ shape
What is a motor unit?
A motoneuron and the muscle fibres it innervates
Describe the Henneman Size Principle. (2)
Small motor units (in terms of cell body and axon diameter) are recruited before large motor units
These units produce low force but are more fatigue resistant
What are the 3 main types of motor unit?
Type I, IIA, IIX
Describe the monosynaptic stretch reflex. (3)
Add load to muscle
Muscle and muscle spindle stretch as arm drops
Reflex contraction initiated by muscle spindle restores arm position
Give 2 examples of polysynaptic reflexes.
Reciprocal inhibition
Golgi tendon reflex
Give 3 examples of ascending and descending pathways.
Dorsal column pathway
Spinothalamic pathway
Corticospinal pathway
