Proprioception

Question 1

What do group 1a sensory endings relay information on?

Answer 1

The dynamic phase of the muscle stretch

Question 2

What do group 2 sensory endings relay information on?

Answer 2

The static phase of the muscle stretch

Question 3

What are the two types of nerve endings in the afferent fibres on the muscle spindle?

Answer 3

Primary (anulospiral) endings

Secondary (flower spray) endings

Question 4

What do gamma motorneurons activate?

Answer 4

Intrafusal fibres (muscle spindle)

Question 5

How does serotonin and noradrenaline affect gamma activity?

Answer 5

Serotonin increases gamma activity (spindles made stiffer- more sensitive)
Noradrenaline decreases gamma activity (spindles made more elastic)

Question 6

What type of nerves are activated in the tendon jerk reflex?

Answer 6

Group 1a afferent- sends signals to the spinal cord

Question 7

What types of nerves are activated in the tonic vibration reflex?

Answer 7

Group 2 afferent fibres

Question 8

How many distinct regions is the SI cortex divided into

Answer 8

4

Question 9

What occurs when the Group 1a afferent firing rate increases during the stretch reflex?

Answer 9

Stimulation of the homonymous muscle and synergistic muscles occurs, as well as relaxation of antagonistic muscles
The reflex counteracts the stretch and makes the muscle more springy