Unit 3: Motor Systems

Question 1

L1: _____ are collagen structures at the junction between a muscle and tendon and detect muscle stretch.

Answer 1

Golgi Tendon Organs

Question 2

L1: _____ are mapped in the motor cortex.

Answer 2

Movements

Question 3

L1: _____ are present in intrafusal muscle fibers and detect muscle stretch.

Answer 3

Muscle spindles

Question 4

L1: _____ motor units are recruited first.

Answer 4

Smaller

Question 5

L1: Motor unit: ______ alpha motor neuron(s) innverating _______.

Answer 5

a single; muscle fibers

Question 6

L1: Which fiber type? Activate quickly, fatigue rapidly

Answer 6

Fast-twich glycolytic

Question 7

L1: Which fiber type? Activate quickly, have many fibers, and fatigue moderately slowly

Answer 7

Fast-twitch oxidative

Question 8

L1: Which fiber type? Fatigue very slowly due to high amounts of myoglobin and many mitochondria

Answer 8

Slow-twitch

Question 9

L1: Which fiber type? Shorten extremely slowly and create isometric tension with low fatiguability

Answer 9

Tonic

Question 10

L2: ______ can sense muscle stretch during muscle contraction via _______ innervation.

Answer 10

Muscle spindles; gamma-motor neuron

Question 11

L2: ______ cannot detect muscle stretch during passive movement

Answer 11

Golgi Tendon Organs

Question 12

L2: ______ neurons are not recruited in reflex pathways.

Answer 12

Gamma-motor

Question 13

L2: Flexion-extension coupling is mediated by __ afferent input from ______ that result in activation of excitatory and inhibitory interneurons in the spinal cord

Answer 13

Ib; Golgi Tendon Organs

Question 14

L2: Golgi Tendon Organis are oriented in ______ with muscle fibers and are innervated by group ______ afferents.

Answer 14

series; Ib

Question 15

L2: In overestimating force needed to lift an object the extrafusal fibers shorten ___ than the muscle spindle fibers, triggering a _____ firing rate of the muscle spindle, and feedback that _____ muscle tension.

Answer 15

more; decreased; decreases

Question 16

L2: In underestimating force needed to lift an object the extrafusal fibers shorten ___ than the muscle spindle fibers, triggering a _____ firing rate of the muscle spindle, and feedback that _____ muscle tension.

Answer 16

less; increased; increases

Question 17

L2: Muscle spindles are oriented in ______ with muscle fibers and are innervated by group _____ afferents.

Answer 17

parallel; Ia and II

Question 18

L2: Smaller motor neurons have _____ input resistance, such that the same stimulation elicits _____ voltage change.

Answer 18

increased; increased

Question 19

L2: Smaller motor units tend to activate more _______-twitch fibers.

Answer 19

Slow

Question 20

L2: Stretching of _____ afferent fibers causes activation of alpha-motor neurons in the stretch muscle and ______ of alpha-motor neurons in the antagonist muscle

Answer 20

Ia; inhibition

Question 21

L2: Which brain structure? Involved in self-cued movements; highly activated during mental rehearsal of movement

Answer 21

Supplementary motor cortex

Question 22

L2: Which brain structure? Involved when movement is initiated by an external cue

Answer 22

Premotor cortex

Question 23

L2: Which brain structure? Invovled in anticipatory responses to a voluntary movement that help control posture and balance.

Answer 23

Reticular formation

Question 24

L2: Which brain structure? Merges auditory and visual information onto a body coordinate system

Answer 24

Superior colliculus

Question 25

L2: Which brain structure? Receives input from mesencephalic motor nucleus to regulate locomotor speed

Answer 25

Reticular formation