Week 1: The Peripheral Nervous System

Question 1

What is the structural difference between peripheral and central nervous system?

Answer 1

• Central: enclosed in bone

- Peripheral: outside of bone

Question 2

What is the clinical difference between peripheral and central nervous system?

Answer 2

• Central: myotomal/dermatomal distribution

- Peripheral: peripheral nerve distribution

Question 3

In the spinal cord, where do we see the transition from CNS to PNS?

Answer 3

Across the spinal nerve between where the spinal roots converge and rami divide

Question 4

Review brachial and lumbosacral plexuses

Answer 4

-

Question 5

Sort axon size by speed, from fastest to slowest

Answer 5

Large myelinated –> Medium myelinated –> Small myelinated –> Unmyelinated

Question 6

Speed of large myelinated axons

Answer 6

70-130 m/s

Question 7

Speed of medium myeliniated axons

Answer 7

12-45 m/s

Question 8

Speed of small myelinated axons

Answer 8

3-30 m/s

Question 9

Speed of unmyelinated axons

Answer 9

0.2-2 m/s

Question 10

Group for large myelinated axons

Answer 10

• A(alpha)

- Ia, Ib

Question 11

Group for medium myelinated axons

Answer 11

• A(delta)

- II, A(beta)

Question 12

Group for small myelinated axons

Answer 12

• B

- A(delta)

Question 13

Group for unmyelinated axons

Answer 13

• C

- C

Question 14

Large myelinated efferents

Answer 14

Extrafusal muscle fibers

Question 15

Medium myelinated efferents

Answer 15

Intrafusal muscle fibers

Question 16

Small myelinated efferents

Answer 16

Presynaptic autonomic

Question 17

Unmyelinated efferents

Answer 17

Postsynaptic autonomic

Question 18

Large myelinated afferents

Answer 18

Spindles, GTOs

Question 19

Medium myelinated afferents

Answer 19

Spindles, touch, vibration, skin stretch, pressure

Question 20

Small myelinated afferents

Answer 20

Nociceptive, temperature, visceral

Question 21

Unmyelinated afferents

Answer 21

Nociceptive, temperature, visceral