Test 3 - Lecture 2 (Proprioception) Flashcards Preview

Neurophysiology > Test 3 - Lecture 2 (Proprioception) > Flashcards

Flashcards in Test 3 - Lecture 2 (Proprioception) Deck (49)
Loading flashcards...
1

Determines joint angles & or angles of joint rotation

Muscle length

2

Provides counteracting force against the external load to stabilize joint positions

Active tension

3

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

Descending corticospinal tracts

4

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

Extrafusal

5

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

Alpha motor neuron, ventral horns

6

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

Synaptic integration

7

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

Level of muscle activation

8

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

Proprioception

9

What are the two main proprioceptors

Muscle spindles, golgi tendon organs

10

Motor neurons that innervate the intrafusal muscle fibers

Gamma motor neurons

11

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

Muscle spindles

12

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

Google tendon organs

13

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

Annulospiral ring

14

Stretching of the annulospiral ring activates mechanosensitve channels causing

Depolarization of the sensory neuron

15

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

Directly

16

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

Nuclear bag fibers (dynamic/static)

17

Characterized by nuclei arranged in a longitudinal row

Nuclear chain fibers (more numerous than nuclear bag fibers)

18

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

Type 1a (primary) afferents

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)

Type II (secondary) afferents

20

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

Ia

21

_____ fibers contribute to the force the muscle is putting out

Extrafusal

22

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

Dynamic gamma motor neurons

23

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

Static gamma motor neurons

24

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

Muscle spindle

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

True

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

Gamma

27

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

Level of fusimotor activity (fusimotor system)

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

Golgi tendon organs

29

Functional unit for a reflex consists of...

- 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)

30

Stereotypic motor response to a particular sensory input

Motor reflex