Movement 3

Question 1

two types of sensory receptors in muscle

Answer 1

muscle spindles

golgi tendon organs

Question 2

describe muscle spindle strcture

Answer 2

fibrous capsule surrounding intrafusal muscle fibres; outside there are extrafusal muscle fibres.

Question 3

describe intrafusal muscle fibres

Answer 3

responsible for stretch sensivitiy as they have stretch sensitive ion channels.
innervated by ia sensory neurons and gamma motor neurons.

Question 4

describe extrafusal muscle fibres

Answer 4

responsible for force generation.

innervated by 1a sensory neurons and alpha/lower motor neurons

Question 5

describe gamma coactivation

Answer 5

when lmns activate extrafusal muscle, muscle spindles slackening, and they’re no longer stretch sensitive.
gamma neurons activate intrafusal muscle fibres, causing their unslackening

Question 6

describe myotatic reflex

Answer 6

kneebone hit, causing lengthening of quadricep

muscle spindle –> 1a –> LMN –> contraction of quadricep

Question 7

describe reciprocal inhibition

Answer 7

for muscles of the same myotatic unit
sensation –> 1a and then either
–> LMN –> excitation of synergist muscle OR
–> inhibitory interneuron –> LMN –> inhibition of antagonist muscle

Question 8

describe golgi tendon organs

Answer 8

found in tendons
innervated by 1b sensory axons
no direct motor innervation

Question 9

characteristics of upper motor neurons

Answer 9

soma in brain - therefore, control voluntary and not reflexive movement as reflexes occur through the spinal cord
axons synapse LMN’s

Question 10

SYMPTOMS OF lesions to lower motor neurons?

Answer 10

flaccid paralysis (complete loss of motor control)
paresis (partial loss)
muscle atrophy
areflexia

Question 11

early symptoms of lesions to upper motor neurons

Answer 11

areflexia
flaccid paralysis
hypotonia

Question 12

later symptoms of lesions to UMNs

Answer 12

hypertonia
hypereflexia (they dampen reflexes usually)
babinski sign