Proprioception

Question 1

Modern evidence suggests minimal role for joint capsule

Answer 1

1. Animal recordings suggest joint capsule afferents provide ambiguous info mainly acting as limit detectors

Question 2

What does the muscle spindle consist of

Answer 2

1.bundle of thin muscle fibres contained w in a capsule
2.situated in paralell with main extrafusal muscle but generates no force
3.wrapped around a pair of sensory axons that detect muscle stretch
4.gamma motor neurons cause active contraction of spindle

Question 3

What does a muscle spindle detect

Answer 3

1.static length of muscle
2.rate of change of muscle stretch

Question 4

What do primary endings of muscle spindle do

Answer 4

Signal position and velocity. Transmitted via 1a afferents. Sensitive to vibration

Question 5

Evidence supporting the role of spindles:

Answer 5

1.prior stretch or contraction significantly affects joint position

Question 6

Golgi tendon organ:

Answer 6

Indirectly contributes to joint rotation sesne- signals force and heaviness

May be important when muscle movement is ambiguous

Question 7

Where is the Golgi tendon organ situated

Answer 7

Between muscle and tendon unlike spindles, golgis are in series with muscle

Question 8

What do spindles lie parallel with

Answer 8

Extrafusal muscle and are sensitive to both muscle position and velocity

Question 9

What is the role of alpha gamma coactjvation

Answer 9

It’s necessary to maintain spindle sensitivity in face of muscle contraction

Question 10

How do Golgi tendons detect force

Answer 10

Via group II afferents

Question 11

Proprioception,ageing and falls

Answer 11

1.ankle proprioception declines with age however proprioception falls link not strong