Test 3 - Lecture 2 (Proprioception)

Question 1

Determines joint angles & or angles of joint rotation

Answer 1

Muscle length

Question 2

Provides counteracting force against the external load to stabilize joint positions

Answer 2

Active tension

Question 3

Convey centrally programmed motor commands into the ventral horn of the spine

Answer 3

Descending corticospinal tracts

Question 4

_____ fibers comprise the main bulk of skeletal muscle, generate force during muscle contraction

Answer 4

Extrafusal

Question 5

Each extrafusal fiber is innervated by a ________, located in the _______ of the spinal cord

Answer 5

Alpha motor neuron, ventral horns

Question 6

The strength of signaling from the alpha motor neurons is determined through

Answer 6

Synaptic integration

Question 7

Is determined by the accumulation of signals (excitatory or inhibitory) that provide input to a alpha motor neurons innervating the muscle

Answer 7

Level of muscle activation

Question 8

Provides information concerning current position & movement of the muscles & joints

Answer 8

Proprioception

Question 9

What are the two main proprioceptors

Answer 9

Muscle spindles, golgi tendon organs

Question 10

Motor neurons that innervate the intrafusal muscle fibers

Answer 10

Gamma motor neurons

Question 11

Are arranged in parallel with the extrafusal fibers; reports the muscle length, along with changes in length

Answer 11

Muscle spindles

Question 12

Are arranged in series with the extrafusal fibers of the associated skeletal muscle

Answer 12

Google tendon organs

Question 13

Sensory nerve ending wrapping around the central part of the intrafusal fiber

Answer 13

Annulospiral ring

Question 14

Stretching of the annulospiral ring activates mechanosensitve channels causing

Answer 14

Depolarization of the sensory neuron

Question 15

The rate of firing from sensory neurons is ______ proportional to the amount of stretch

Answer 15

Directly

Question 16

Characterized by a large number of nuclei packed within the mid-portion

Answer 16

Nuclear bag fibers (dynamic/static)

Question 17

Characterized by nuclei arranged in a longitudinal row

Answer 17

Nuclear chain fibers (more numerous than nuclear bag fibers)

Question 18

Arise from the annulospiral rings surrounding all three fiber types; largest fibers, fastest conducting, rapidly adapting (mainly report changes in length)

Answer 18

Type 1a (primary) afferents

Question 19

Arise from nerve endings located distal to the center of nuclear chain & static nuclear bag fibers; intermediate diameter, relatively fast conducting, slowly adapting (mainly report static length)

Answer 19

Type II (secondary) afferents

Question 20

During the lengthening of a muscle… the type ____ fiber reports the largest signaling

Answer 20

Ia

Question 21

_____ fibers contribute to the force the muscle is putting out

Answer 21

Extrafusal

Question 22

Nerve terminals are called plate endings; innervate dynamic nuclear bag fibers

Answer 22

Dynamic gamma motor neurons

Question 23

Nerve terminals are called trail endings; innervate static nuclear bag fibers, as well as nuclear chain fibers

Answer 23

Static gamma motor neurons

Question 24

Provides sensory input for the CNS to continually monitor the length & changes of length in the muscle

Answer 24

Muscle spindle

Question 25

T/F: co-activation is the theory that gamma motor neurons that innervate intrafusal fibers HAVE to contract when the alpha motor neurons contract the extrafusal fibers for a muscle to function properly

Answer 25

True

Question 26

Activating ____ motor neurons during a muscle contraction maintains sufficient tension on the mechanoreceptive nerve endings to allow them to continue to signal the rate & extent of change in muscle length

Answer 26

Gamma

Question 27

The amount of dynamic & static activity during a certain movement is called

Answer 27

Level of fusimotor activity (fusimotor system)

Question 28

Report the force & tension generated by a muscle, arising from its extrafusal fibers contracting against the external load; give rise to type Ib afferent fibers

Answer 28

Golgi tendon organs

Question 29

Functional unit for a reflex consists of...

Answer 29

- sensor (proprioceptors) - afferent pathway (type Ia or II sensory nerves) - integrating center (synaptic relay through spinal interneurons & motor neurons) - effector pathway (motor nerves) - effector (skeletal muscles)

Question 30

Stereotypic motor response to a particular sensory input

Answer 30

Motor reflex

Question 31

Two factors that effect "lowering the cup"

Answer 31

- increase in the load Or - reduction in the level of activation to the flexor

Question 32

Two factors which result in "raising the cup"

Answer 32

- reduction in the load Or - increase in the level of activation

Question 33

To maintain stable position: the muscles starts to lengthen = _____ activation, to counteract

Answer 33

Increase

Question 34

To maintain stable position: the muscles starts to shorten = _____ activation, to counteract

Answer 34

Decrease

Question 35

The act of counteracting a disturbance to a stable position or tension

Answer 35

Reflex

Question 36

To maintain stable tension: the tension starts to increase = _____ activation, to counteract

Answer 36

Decrease

Question 37

To maintain stable tension: the tension starts to decrease = _____ activation, to counteract

Answer 37

Increase

Question 38

Two alpha motor neuron reflexes

Answer 38

Myotatic & inverse myotatic reflex

Question 39

In response to input from muscle spindles; length (reflex for stabilization of muscle length)

Answer 39

Myotatic reflex

Question 40

In response to input from golgi tendon organ; tension (reflex for stabilization of muscle tension)

Answer 40

Inverse myotatic reflex

Question 41

Ia afferent fibers provide _______ input to motor neurons interacting the ______ & ______ muscles

Answer 41

- monosynaptic excitatory - homonymous - synergist

Question 42

Fiber types used in myotatic muscle reflex

Answer 42

Ia (excitatory input) | - increase in Ia signaling - increased motor signaling to muscles (leading to muscle shortening)

Question 43

Fiber used in inverse myotatic muscle reflex

Answer 43

Ib (inhibitory input) | - increase Ib signaling - decreased motor signaling (release of tension)

Question 44

Ib afferent fibers provide _______ input to motor neurons interacting the ______ & ______ muscles

Answer 44

- inhibitory interneurons - homonymous - synergist

Question 45

Contributes to an appropriate balancing between the agonist & antagonist muscles acting upon the joint

Answer 45

Reciprocal innervation

Question 46

Ia afferent input _______ to provide input to multiple motor neurons for the homonymous & synergist muscles

Answer 46

Diverges

Question 47

afferent proprioceptive sensory input combines with the descending efferent motor commands that are all ______ upon an alpha motor neuron

Answer 47

Convergent

Question 48

Inhibitory interneuron that is stimulated by fibers branching off the motor nerve, to synapse upon the motor neuron from which that motor nerve arose

Answer 48

Renshaw cell interneuron

Question 49

Circuit serves to restrain motorneuron firing relative to its excitatory inputs; stabilize the current output relative to the current input

Answer 49

Recurrent feedback inhibition