Lesson 2: Neural Control of Movement

Question 1

Two parts of the nervous system

Answer 1

CNS
PNS

Question 2

6 major areas of the brain

Answer 2

Medulla oblongata
Pons
Midbrain
Cerebellum
Encephalon
Cerebrum

Question 3

3 parts of the brainstem

Answer 3

Medulla
Pons
Midbrain

Question 4

Fine motor controls have more/less muscle fibers per unit

Answer 4

less

Question 5

Gross motor controls have more/less muscle fibers per unit

Answer 5

more

Question 6

Parts of the alpha motor neuron:

Answer 6

Cell body, axon, dendrites

Question 7

The ______ houses the neuron’s control center for signal transmission

Answer 7

cell body

Question 8

The ___ extends from the cell body to deliver the signal to the muscle

Answer 8

axon

Question 9

The _______ are small and short neural branches that receive impulses and conduct them toward the cell body

Answer 9

dendrites

Question 10

Lipoprotein membrane that wraps around the axon over most of its length

Answer 10

myelin sheath

Question 11

What is the myelin sheath made from?

Answer 11

Lipoprotein
Fat

Question 12

What is the purpose of the myelin sheath?

Answer 12

Insulates and speeds up nerve transmission

Question 13

What is the thin/outermost layer that covers the myelin sheath?

Answer 13

Neurilemma

Question 14

Nodes that interrupt the myelin sheath every 1 to 2 mm and allow the neuron to depolarize (provide stimulus for movement)

Answer 14

Nodes of Ranvier

Question 15

What is the purpose of the nodes of Ranvier on the axon?

Answer 15

Allow the neuron to depolarize and provide a stimulus for movement

Question 16

Conduction speed of a nerve fiber is directly related to the _______ and the _________.

Answer 16

muscle fiber’s diameter
Thickness of the myelin sheath

Question 17

The bigger the nerve fiber, the bigger/smaller the muscle fiber

Answer 17

bigger

Question 18

Another name for the neuromuscular junction is the _____ ______

Answer 18

motor endplate

Question 19

Where does excitation typically occur?

Answer 19

The neuromuscular junction

Question 20

The post-synaptic membrane (on muscle fiber) involve “folds” that allow for ________

Answer 20

greater surface area of transmission

Question 21

The electrical stimulus at the post-synaptic membrane creates an ______ _______

Answer 21

Action potential

Question 22

Threshold for excitation

Answer 22

change in voltage on the post synaptic membrane required to produce an action potential

Question 23

What is spatial summation?

Answer 23

simultaneous “summing’” of stimuli from surrounding terminals (“space”)

Question 24

What is temporal summation?

Answer 24

Simultaneous “summing” of stimuli from repeated stimulation (“time”)

Question 25

The larger the motor unit, the more/less force it can produce

Answer 25

MORE

Question 26

Type _ muscle fibers have the smallest motor units

Answer 26

I

Question 27

Type _ muscle fibers have the largest motor units

Answer 27

IIx & IIb

Question 28

Type _ muscle fibers have larger but not the largest motor units

Answer 28

IIa

Question 29

What is the reflex arc?

Answer 29

the nerve pathway involved in a reflex action including at its simplest a sensory nerve and a motor nerve with a synapse between

Question 30

Arrangement of the reflex arc:

Answer 30

1) afferent neurons transmit sensory input from peripheral receptors and enter through the dorsal region of the spinal cord 2) afferent neurons synapse (interconnect) with efferent neurons through interneurons in the spinal cord 3) efferent neurons exit the cord through ventral region and provide signaling to muscles

Question 31

Does the reflex arc directly involve the spinal cord?

Answer 31

Yes

Question 32

Does the reflex arc directly involve the brain?

Answer 32

No

Question 33

Muscles and tendons have highly specialized sensory receptors sensitive to _____, _____, and ______

Answer 33

stretch, tension, pressure

Question 34

The receptors in the muscles and tendons that are sensitive to stretch, tension, and pressure are called _________

Answer 34

proprioceptors

Question 35

2 types of proprioceptors

Answer 35

Muscle Spindles Golgi Tendon Organs

Question 36

Muscle spindles provide mechano-sensory information about change in ____ _____ ____

Answer 36

muscle fiber length

Question 37

Where are the muscle spindles located?

Answer 37

In the muscle fiber

Question 38

the process by which a muscle spindle detects, responds to, and modulates change in the length of muscle fibers

Answer 38

Stretch reflex

Question 39

What triggers the stretch reflex?

Answer 39

Change in the length of muscle fiber

Question 40

Three main components of the stretch reflex:

Answer 40

1) Muscle spindle that responds to stretch 2) Afferent nerve fiber that carries the sensory impulse from the spindle to the spinal cord 3) Efferent spinal cord motor neuron that activates the attached muscle fiber

Question 41

What does the muscle spindle of the stretch reflex do?

Answer 41

Responds to the stretch

Question 42

What does the afferent nerve fiber of the stretch reflex do?

Answer 42

Carries the sensory impulse from the muscle spindle to the spinal cord

Question 43

What does the efferent spinal cord motor neuron of the stretch reflex do?

Answer 43

Activates the attached muscle fiber

Question 44

Does the stretch reflex involve interneuron?

Answer 44

No

Question 45

Example of the stretch reflex

Answer 45

heavier weight added will have an initial reflex response; patellar tap reflex

Question 46

The GTO responds to _____/____ ____

Answer 46

tension; force production

Question 47

sensory receptors that detect differences in the tension generated by active muscles

Answer 47

GTO

Question 48

Where are GTOs located?

Answer 48

In the tendon (which attaches muscle to bone, FYI)

Question 49

GTOS respond to tension created in the muscle when it lengthens/shortens and tension when the muscle _______ _______

Answer 49

shortens; stretches passively

Question 50

What does the GTO do when responding to EXCESSIVE tension?

Answer 50

Elicits reflex inhibition of the muscle cells they supply Protect the muscle against excessive force Protect the muscle and surrounding tissue from injury during an unaccustomed movement or excessive load

Question 51

True or False: The GTO aims to limit damage, like a golf cart governor.

Answer 51

True

Question 52

Explain the three steps of the GTO reflex arc

Answer 52

1) excessive tension on the tendon provides an afferent stimulus to the spinal cord 2) an inhibitory interneuron connects the afferent and efferent pathways 3) efferent neuron sends signal to decrease tension/inhibit force

Question 53

Does the GTO reflex arc involve an interneuron?

Answer 53

Yes