Section 3

Question 1

Axon classification method differentiates fiber’s conduction velocity; used for both motor and sensory axons

Answer 1

Electrophysiological classification

Question 2

Axon classification method classifies axons by diameter and myelination; applies only to sensory axons

Answer 2

Roman numeral classification

Question 3

What types of axons are class A?

Answer 3

Motor and sensory

Question 4

What types of axons are class B?

Answer 4

Motor only

Question 5

What types of axons are class C?

Answer 5

Motor and sensory

Question 6

What type of axons are preganglionic axons in the ANS? Postganglionic?

Answer 6

Type B; Type C

Question 7

What 2 factors affect impulse conduction velocity?

Answer 7

1. Axon diameter: larger = faster conduction velocity

2. Myelin coated

Question 8

Electrical stimulation causes action potentials to move through each axon in the nerve trunk; the signal recorded from the nerve trunk is the sum of all the individual APs from each nerve axon and is named the _____________.

Answer 8

Compound action potential

Question 9

If some nerve(s) in the autonomic trunk are pathological, you will see an (increase/decrease) in compound action potential.

Answer 9

Decrease

Question 10

Conduct action potentials toward the spinal cord and brain

Answer 10

Sensory neurons

Question 11

Conduct action potentials away from the spinal cord to the skeletal muscle or smooth muscle

Answer 11

Motor neurons

Question 12

Types A and B fibers have (myelinated/unmyelinated) axons whereas type C fibers has (myelinated/unmyelinated) axons.

Answer 12

Myelinated; unmyelinated

Question 13

Axon types A and B fibers conduct APs at (faster/slower) velocities than type C fibers

Answer 13

Faster

Question 14

Roman numeral sensory fiber group classification and speed that corresponds with type A alpha.

Answer 14

I, 120 m/s

Question 15

Roman numeral sensory fiber group classification and speed that corresponds with type A beta.

Answer 15

II, 70 m/s

Question 16

Roman numeral sensory fiber group classification and speed that corresponds with type A delta.

Answer 16

III, 15 m/s

Question 17

Roman numeral sensory fiber group classification and speed that corresponds with type C.

Answer 17

IV, 2 m/s

Question 18

Axons of A alpha motor axons innervate ______, and velocity is ___ m/s.

Answer 18

Extrafusal (fast twitch skeletal m. fibers); 120

Question 19

Axons of A alpha Ia sensory axons innervate ______, and velocity is ___ m/s.

Answer 19

Muscle spindles (primary affarent m. spindle fiber); 120

Question 20

Axons of A alpha Ib sensory axons innervate ______, and velocity is ___ m/s.

Answer 20

Golgi tendon organs and pressure receptors; 120

Question 21

Axons of A beta motor axons innervate ______, and velocity is ___ m/s.

Answer 21

Estrafusal (slow twitch m. fibers); 70

Question 22

Axons of A beta II sensory axons innervate ______, and velocity is ___ m/s.

Answer 22

Muscle spindles (secondary affarent m. spindle fiber); 70

Question 23

Axons of A gamma motor axons innervate ______, and velocity is ___ m/s.

Answer 23

Intrafusal m. fibers of muscle spindle; 40

Question 24

Axons of A delta III sensory axons innervate ______, and velocity is ___ m/s.

Answer 24

Receptors of pain, touch, pressure, temperature (fast pain); 15

Question 25

Axons of B motor axons innervate ______, and velocity is ___ m/s.

Answer 25

Preganglionic autonomic; 14

Question 26

Axons of C motor axons innervate ______, and velocity is ___ m/s.

Answer 26

Postganglionic anutonomic; 2

Question 27

Axons of C IV sensory axons innervate ______, and velocity is ___ m/s.

Answer 27

Receptors of pain and temperature (slow pain); 2

Question 28

In relation to the length of muscle spindle fibers, what do type I nerve axons sense?

Answer 28

Rate of change of length in m. fiber

Question 29

In relation to the length of muscle spindle fibers, what do type II nerve axons sense?

Answer 29

Length of m. fiber (if it’s short or long)

Question 30

Increased impulse frequency in Ia fibers results in ______________.

Answer 30

Increased m. force

Question 31

Increased impulse frequency in Ib fibers results in _____________.

Answer 31

Decreased m. force

Question 32

Class II afferent axons innervates the _____ or secondary endings of the muscle spindle receptor and pressure receptors

Answer 32

Flower spray

Question 33

Class III afferent axons innervate ______ (fast pain), _____ (course) receptors, and ______ (mostly cold).

Answer 33

Nociceptors; touch; thermoreceptors

Question 34

Class IV afferent axons innervate ______ (slow pain), _______ receptors, and ______ (cold and warm)

Answer 34

Nociceptors; itch and tickle; thermoreceptors

Question 35

Largest axons have (lowest/highest) threshold to slowly rising electrical stimulus

Answer 35

Lowest

Question 36

AP reaching recording electrode first traveling in the ______ axon, followed by APs traveling in the _______ diameter axons.

Answer 36

Largest; smaller

Question 37

Cutaneous (touch) mechanoreceptors are ______ adapting, whereas musculoskeletal mechanoreceptors are _______ adapting

Answer 37

Slow; fast

Question 38

A alpha diameter

Answer 38

22 um

Question 39

A beta diameter

Answer 39

13 um

Question 40

A gamma diameter

Answer 40

8 um

Question 41

A delta diameter

Answer 41

5 um

Question 42

B diameter

Answer 42

3 um

Question 43

C diameter

Answer 43

1 um