Lecture 16 - Movement and muscles

Question 1

what are bundles muscle fibres called? what are they surrounded by?

Answer 1

fascicles, perimysium

Question 2

every action potential arriving at the neuromuscular synapse causes a contraction meaning it is a ….. ……. synapse

Answer 2

high fidelity

Question 3

where does the action potential cause calcium to be released from ?

Answer 3

sarcoplasmic reticulum

Question 4

what does calcium bind to when released from the sarcoplasmic reticulum?

Answer 4

troponin

Question 5

during which period of a muscle contraction is there twitching as the neurotransmitter diffuses across the NMJ? how long is this period?

Answer 5

latent period, 5msec

Question 6

what is kinaesthesia/proprioception?

Answer 6

awareness of position and state of our various body parts without vision

Question 7

in fused tetanus, the rate of calcium release from the SR = the rate of what?

Answer 7

the rate of sequestering back causing constant contraction therefore

Question 8

what are the 2 types of afferent fibres in muscle spindles? are the fibres extra or intrafusal?

Answer 8

1a and 2, intrafusal

Question 9

what do muscle spindle fibres detect about muscles?

Answer 9

stretch

Question 10

in muscle spindles what do group 1a afferents detect?

Answer 10

velocity of change of stretch

Question 11

in muscle spindles what do group 2 afferents detect? what can’t they detect?

Answer 11

change in length of muscle (can’t detect relaxing)

Question 12

what type of afferent fibres do golgi tendon organs have?

Answer 12

1b

Question 13

what do 1a afferent fibres in golgi tendon organs detect?

Answer 13

sense force/tension in collagen fibres in tendons

Question 14

which motoneurons do extrafusal fibres connect to?

Answer 14

alpha

Question 15

which motoneurons do intrafusal fibres connect to?

Answer 15

gamma

Question 16

cell bodies of motoneurons that innervate limb muscles are found in which layers within the spinal cord?

Answer 16

ventral layers

Question 17

in a motor unit each neuron connects …… muscle fibres but each muscle fibre gets an input from …… neuron

Answer 17

multiple, one

Question 18

in the recruitment of motor units the first unit recruited has to be …… than the 2nd one and so on. e.g first recruited is a type ….. muscle fibre and second is a type ….

Answer 18

smaller, 1, 2

Question 19

name the 5 descending pathways

Answer 19

corticospinal, rubrospinal, reticulospinal, tectospinal, vestibulospinal

Question 20

which 2 things does the corticospinal tract control?

Answer 20

voluntary movements and fine manipulative movements

Question 21

what does the rubrospinal tract control?

Answer 21

the control of voluntary movements

Question 22

what 4 things does the reticulospinal tract control?

Answer 22

posture, locomotion, voluntary movements, grasping

Question 23

what does the tectospinal tract control?

Answer 23

head and neck movement

Question 24

what does the vestibulospinal tract control? 2 things

Answer 24

posture and balance

Question 25

name the 4 inputs to motoneurons

Answer 25

descending pathways, peripheral (Sensory), inputs from spinal interneurons, cutaneous

Question 26

reciprocal inhibition in inputs from spinal interneurons is done by which group of fibres?

Answer 26

1a

Question 27

the inhibitory tendon reflex is done by which group of nerve fibres?

Answer 27

1b

Question 28

in cutaneous touch inputs to motoneurons which interneurons excite motoneurons?

Answer 28

d13