Peripheral Nervous System

Question 1

3 Components of PNS

Answer 1

• Cranial Nerves
• Spinal Nerves
• Ganglia

Question 2

Where is gray matter in the PNS?

Answer 2

in the ganglia

(dorsal root and autonomic)

Question 3

Where is white matter in the PNS?

Answer 3

in cranial and spinal nerves

Question 4

What makes a nerve an organ?

Answer 4

it contains different types of tissue

nervous tissue wrapped in layers of of connective tissue and containing blood vessels lined with epithelial tissue

Question 5

Schwann cells

Answer 5

• cells that surround PNS axons and myelinate them

Question 6

mixed nerves

Answer 6

nerves containing both sensory and motor axons

Question 7

nerve fiber

Answer 7

a long axon

Question 8

nerve

Answer 8

a collection of nerve fibers (axons) bundled into fascicles, all surrounded by epineurium (tough fibrous CT sheath)

Question 9

Cranial Nerves

Answer 9

• 12 nerves numbered I-XII (rostral to caudal)
• attach to brain, pass through foramina of skull and innervate head and neck structures (except vagus)
• contain both sensory and motor nerve fibers

Question 10

Which cranial nerves attach to the forebrain?

Answer 10

I (Olfactory) and II (Optic)

Question 11

Which cranial nerves attach to the brain stem?

Answer 11

III-XII (all but optic and olfactory)

Question 12

Sensory Neurons of Cranial Nerves

Answer 12

• cell bodies within receptor organs (nose, eye, tongue)
• cranial sensory ganglia along some cranial nerves external to brain

Question 13

Motor Neurons of Cranial Nerves

Answer 13

• cell bodies in nuclei of brain stem

Question 14

cranial nerve classification

Answer 14

• Sensory
• Motor
• Mixed

Question 15

Cranial Nerve I

Answer 15

Olfactory Nerve

• Sensory nerve of smell

Question 16

Answer 16

structures on inferior side of frontal lobes supported by cribriform plate of ethmoid bone which leads to nerve filaments that sense smell

Question 17

bundles of axons connecting olfactory bulbs to brain

Answer 17

olfactory tracts

Question 18

Cranial Nerve II

Answer 18

Optic Nerve

• sensory nerve of vision

Question 19

crossing of highlighted structures

Answer 19

optic chiasm

• crossing of optic nerves directly inferior to the hypothalamus

Question 20

2

Answer 20

optic tract

• continuation of optic nerve from optic chiasm to the thalamus

Question 21

Cranial Nerve III

Answer 21

Oculomotor Nerve

• motor neurons
• innervates 4 extrinsic eye muscles

Question 22

Cranial Nerve IV

Answer 22

Trochlear Nerve

• motor nerve
• innervates one extrinsic eye muscle (superior oblique)

Question 23

Cranial Nerve V

Answer 23

Trigeminal Nerve

• mixed nerve
• sensory innervation to face, chewing muscles

Question 24

Cranial Nerve VI

Answer 24

Abducens Nerve

• motor nerve
• abducts the eyeball (via lateral rectus muscle)

Question 25

Cranial Nerve VII

Answer 25

**Facial Nerve** - _mixed_ nerve - innervates facial muscles for expression - sensory innervation for taste

Question 26

Cranial Nerve VIII

Answer 26

**Vestibulocochlear Nerve** - _sensory_ nerve for hearing and balance

Question 27

Cranial Nerve IX

Answer 27

**Glossopharyngeal Nerve** - _mixed_ nerve - sensory innervation to tongue - motor innervation to pharynx

Question 28

Cranial Nerve X

Answer 28

**Vagus Nerve** - _mixed_ nerve - sensory and motor innervation for pharynx, larynx and viscera

Question 29

Cranial Nerve XI

Answer 29

**Accessory Nerve** - _motor_ nerve - accessory part of Vagus nerve - motor innervation to neck and upper back

Question 30

Cranial Nerve XII

Answer 30

**Hypoglossal Nerve** - _motor_ nerve - runs inferior to tongue, innervating its muscles

Question 31

Cranial Nerve Names and #s Mnemonic

Answer 31

**_O_**h, **_O_**h, **_O_**h, **_T_**o **_T_**ouch **_A_**nd **_F_**eel **_V_**ery **_G_**ood **_V_**elvet, **_HA_**! 1. Olfactory 2. Optic 3. Oculomotor 4. Trochlear 5. Trigeminal 6. Abducens 7. Facial 8. Vestibulocochlear 9. Glossopharyngeal 10. Vagus 11. Accessory 12. Hypoglossal

Question 32

Mnemonic for Nerve Types of Cranial Nerves I-XII (**_S_**ensory, **_M_**otor or **_B_**oth)

Answer 32

**_S_**ome **_S_**ay **_M_**arry **_M_**oney **_B_**ut **_M_**y **_B_**rother **_S_**ays **_B_**ig **_B_**rains **_M_**atter **_M_**ore

Question 33

Spinal Nerves

Answer 33

31 pairs attaching to SC through dorsal and ventral roots: ## Footnote 8 Cervical (one from above atlas vertebrae) 12 Thoracic 5 Lumbar 5 Sacral 1 Coccygeal

Question 34

which set of spinal nerves?

Answer 34

Cervical Nerves - 1st pair superior to atlas - last pair inferior to C7

Question 35

which set of spinal nerves?

Answer 35

thoracic nerves - 12 pairs T1-12 - exit below vertebra of same number

Question 36

which set spinal nerves?

Answer 36

lumbar nerves - L1-5 - exit below vertebra of same number

Question 37

which set of spinal nerves?

Answer 37

sacral nerves - S1-5 - exit below vertebra of same number

Question 38

name of most inferior set of nerves pictured

Answer 38

coccygeal nerves - 1 pair named Co1

Question 39

Nerve Plexus

Answer 39

- networks of intersecting nerves - originate from anterior rami of all spinal nerves but T2-T12

Question 40

Answer 40

cervical plexus - anterior rami of C1-4 - innervate skin/muscles of neck and diaphragm - **Phrenic Nerve**

Question 41

Answer 41

**brachial plexus** - C5 through T1 - innervates skin and muscles of arms - **Axillary, Radial, Median** and **Ulnar Nerves**

Question 42

Answer 42

**lumbar plexus** - L1 - L4 - innervates anterior/medial thigh and skin of medial leg **Femoral** and **Obturator Nerves**

Question 43

the grouping of nerves shown here

Answer 43

sacral plexus - L4, L5 and S1-S4 - innervates most of lower limbs - **Sciatic Nerve**

Question 44

the small yellow nodules lined up parallel to the spine here

Answer 44

paravertebral ganglia - AKA sympathetic trunk/chain - on both sides of vertebral column from neck to pelvis - joined to ventral rami of spinal nerves by rami communicantes - bundles of neuron bodies of the sympathetic nervous system