proprioception

Question 1

what is the meaning of proprioception ?

Answer 1

sense of relative position of neighbouring parts of the body

Question 2

what does modern evidence suggest about joint capsules? (2)

Answer 2

good for injury prevention

people with hip replacements still have good sense of joint placement despite new joint

Question 3

describe characteristics of a muscle spindle

Answer 3

bundle of fibres in a capsule

parallel with main extrafusal

wrapped around sensory axons

gamma neurons cause contraction of spindle

alpha neurones innervate the muscle

Question 4

what do the sensory axons do in terms of the muscle spindle

Answer 4

detect the stretch

detects mechanical deformation

Question 5

what’s meant by intrafusal and extrafusal ?

Answer 5

intra - sindle itself

extra - main body of muscle

Question 6

what does the muscle spindle detect ? (2)

Answer 6

static length of muscle - position

rate of change of muscle stretch - velocity

position + velocity

Question 7

what happens when length of muscle fibre changes in muscle spindles ?

Answer 7

mechanical deformation of axons

opens ion channels

changes membrane potential and firing rate of axon

Question 8

what are primary endings in the muscle spindle ? (3)

Answer 8

signal position and velocity

transmitted via 1a afferents

sensitive to vibrations

Question 9

what are secondary endings in the muscle spindle ? (2)

Answer 9

control position only

transmitted via group 2 afferents

Question 10

what are gamma fibres in the muscle spindle ? (3)

Answer 10

contractile element of spindle

no useful force output

keep spindle taught

Question 11

what is alpha- gamma coactivation ?? (2)

Answer 11

maintains sensitivity of spindle in the face of changing the muscle length

helps keep taut to be sensitive and stop slack

Question 12

what happens during alpha gamma coactivation ? (4)

Answer 12

1a spindle afferent continuously fires to signal muscle length

contraction of muscle causes spindle to slacken

this reduces firing rate and loss of sensitivity

gamma activation keep spindle taut

Question 13

how does vibration effect muscles ?

Answer 13

activates 1a afferents

creates illusion of muscle stretch - position and velocity illusions

Question 14

explain characteristics of the Golgi tendon organ (3)

Answer 14

indirectly contributes to rotation sense - signals force + heaviness

in series w muscle

on interface w tendon and muscle

Question 15

what is a difference between golgi organ tendon and muscle spindle ?

Answer 15

(GTO) records tension compared to recording length (MS)

Question 16

why is golgi tendon rogan useful when muscle movement is ambiguous ?

Answer 16

helps brain realise how force is being used

e.g. concentric vs eccentric movement in muscles can indicate why body is swaying

Question 17

if the GTO and MS where artificially stimulated what is the main difference when the muscle contracts ?

Answer 17

MS goes quiet due to slack

GTO shows increased firing rate

Question 18

when conducting experiments into why proprioception is useful, what did they find ?

Answer 18

testing sensory thresholds help detects which sense is more important

proprioception can allow you to keep boy upright using just your ankles

Question 19

why is interaction with vestibular system important ?

Answer 19

allows connect of head orientation

proprioception using neck muscles help with head orientation

Question 20

what was found about age and proprioception ?

Answer 20

no strong link between falls and proprioception

ankle proprioception declines with ages

Question 21

why is peripheral neuropathy associated with falls ?

Answer 21

blow blood flow from e.g. diabetes can reduce sensation in limbs which can lead to falls

Question 22

what was found in research about postural sway w eyes open and eyes closed? (3)

Answer 22

people say more with eyes closed

disproportional increase in sway in weaker people - can’t use proprioceptive sense

stronger muscles help w proprioception