Anatomy of the PNS

Question 1

What is the basic unit of the nervous system?

Answer 1

Neuron

Question 2

What is a collection of nerve cell bodies called in the CNS?

Answer 2

Nucleus

Question 3

What is a collection of nerve cell bodies called in the PNS?

Answer 3

Ganglion

Question 4

What produces the myelin sheath in the PNS?

Answer 4

Schwann cells

Question 5

What produces the myelin sheath in CNS?

Answer 5

Oligodendrocytes

Question 6

What are the two main types of neurones?

Answer 6

Multipolar

Unipolar

Question 7

Describe a multipolar neuron

Answer 7

2 or more dendrites
All motor neurones of skeletal muscle and ANS
Cell body found in CNS

Question 8

Describe a unipolar neuron

Answer 8

Double process
Aka psedounipolar/sensory
Cell body found in PNS

Question 9

In which direction do impulses travel in motor (efferent) nerves?

Answer 9

Impulse move towards the body wall, cavity or organ

Question 10

In which direction do impulses travel in sensory (afferent) nerves?

Answer 10

Impulses move towards the brain

Question 11

What can a nerve be defined as?

Answer 11

A collection of axons surrounded by connective tissue and blood vessels

Question 12

What is another name for a nerve in the CNS?

Answer 12

Tract

Question 13

What are the two modalities of nerves?

Answer 13

Single modality

Mixed modality

Question 14

Give examples of nerves with single modality

Answer 14

Somatic motor, somatic sensory, special sensory, sympathetic, parasympathetic, visceral afferent

Question 15

Give examples of nerves with mixed modality

Answer 15

Somatic motor, somatic sensory and sympathetic all together in one nerve

Question 16

Give examples of ‘named’ peripheral nerves

Answer 16

Trigeminal
Femoral
Radial

Question 17

Where are CN I and II found?

Answer 17

Forebrain

Question 18

Where is CN V found?

Answer 18

Pons

Question 19

Where are CN VI, VII, VIII found?

Answer 19

Junction between pons and medulla

Question 20

Where are CN IX, X and XII found?

Answer 20

Directly from medulla

Question 21

Where is CN XI found?

Answer 21

Spinal cord

Question 22

How many pairs of spinal nerves are there?

Answer 22

31 pairs

Question 23

Where are spinal nerves only ever found?

Answer 23

Intervertebral foramina

Question 24

From the spinal cord describe the path of the spinal nerve

Answer 24

Anterior and posterior rootlets converge to become anterior and posterior roots
The anterior and posterior root converge to become the spinal nerve
The spinal nerve then divides into anterior and posterior rami

Question 25

Describe the path that all sensory axons take

Answer 25

Sensory axons pass from spinal nerve into POSTERIOR root then into posterior rootlets then into posterior horn of spinal cord

Question 26

Describe the path that all motor axons take

Answer 26

Motor axons pass from anterior horn of spinal cord into anterior rootlets then into anterior root then into spinal nerve

Question 27

Which type of nerves pass through the spinal nerve?

Answer 27

Both sensory and motor!

Question 28

Each spinal nerve pair supplies a body segment with....

Answer 28

General sensory supply to all structures Somatic motor supply to skeletal muscles Sympathetic nerve supply to skin and smooth muscle of arterioles

Question 29

Do spinal nerves contain parasympathetic?

Answer 29

Never! | Only contain sympathetic nerves

Question 30

What is a dermatome?

Answer 30

Area of skin supplied with sensory innervation from single spinal nerve Also supplies sensory innervation to deeper structures

Question 31

What is a myotome?

Answer 31

Skeletal muscles supplied with motor innervation from a single spinal nerve May be deep to dermatome of same spinal nerve (not always)

Question 32

Give an example of a myotome that is not deep to the same dermatome

Answer 32

The diaphragm | Innervated by phrenic nerve- C3,4,5- the dermatome does not match the myotome on the surface

Question 33

What are 2 landmarks on the trunk of the dermatome map

Answer 33

Male nipple- T4 segment | Umbilicus- T10 segment

Question 34

Which dermatomes cover posterior scalp, neck and shoulder?

Answer 34

C2-C4

Question 35

Which dermatomes cover upper limb?

Answer 35

C5-T1

Question 36

Which dermatomes cover lower limb, gluteal region and perineum?

Answer 36

L2-S3

Question 37

Which spinal nerves form the cervical plexus?

Answer 37

C1-C4

Question 38

Which spinal nerves form the brachial plexus?

Answer 38

C5-T1

Question 39

Which spinal nerves form the lumbar plexus?

Answer 39

L1-L4

Question 40

Which spinal nerves form the sacral plexus?

Answer 40

L5-S4

Question 41

Describe sympathetic outflow

Answer 41

Originates from autonomic control centres in brain, passes down spinal cord Exits spinal cord with T1-L2 spinal nerves

Question 42

Where do presynaptic axons that innervate the heart originate?

Answer 42

Presynaptic axons synapse in T1 or cervical paravertebral ganglia

Question 43

Where do postsynaptic axons that innervate the heart synapse?

Answer 43

Postsynaptic axons pass in cardiopulmonary splanchnic servers to the SA & AV nodes and the myocardium

Question 44

Describe parasympathetic outflow

Answer 44

Presynaptic parasympathetic axons leave CNS via cranial nerves III, VII, IX and X and sacral spinal nerves

Question 45

From the cranial and spinal nerves where does parasympathetic travel via?

Answer 45

Ciliary ganglion in eye Parasympathetic ganglia in head- lacrimal gland and salivary gland Vagus nerve- organs of neck, chest and abdomen Sacral spinal nerves- handgun, pelvis and perineum