Cranial Nerves & Reflexes

Question 1

Are Efferent fibers:

Motor or Sensory?

Answer 1

Motor

Question 2

Are Afferent fibers:

Motor or Sensory?

Answer 2

Sensory

Question 3

How many pairs of cranial nerves are there?

Answer 3

12 pairs

Question 4

All cranial nerves distribute to the head and neck except 1…which 1?

Answer 4

CN X: Vagus

Goes to thorax and abdomen

Question 5

Which cranial nerves are pure sensory and carry special senses?

Answer 5

1, 2, 8

• CN I: Olfactory
• CN II: Optic
• CN VIII: Vestibulocochlear

**smell, vision, hearing and equilibrium**

Question 6

Which cranial nerves are pure motor and control extraocular eye movements?

Answer 6

3, 4, 6

• CN III: Oculomotor
• CN IV: Trochlear
• CN VI: Abducens

Question 7

Which cranial nerves are pure motor and innervate the SCMs, traps and tongue?

Answer 7

11 & 12

• CN XI: Accessory
• CN XII: Hypoglossal

Question 8

Which cranial nerves are MIXED sensory and motor?

Answer 8

5, 7, 9, 10

• CN V: Trigeminal
• CN VII: Facial
• CN IX: Glossopharyngeal
• CN X: Vagus

Question 9

What does CN I do?

Answer 9

CN I: Olfactory

Smell

(pure sensory)

Question 10

What does CN II do?

Answer 10

CN II: Optic

Vision

(pure sensory)

Question 11

What do CN II & III do?

Answer 11

Pupillary Reflexes

• CN II: Optic (sensory)
• CN III: Oculomotor (motor)

Question 12

What do CN III, IV, & VI do?

Answer 12

Extraocular movements

• CN III: Oculomotor - turns eyes up, down, in

Elevates eye lid

• CN IV: Trochlear - turns adducted eye down
• CN VI: Abducens - turns eye out

Question 13

What does CN V do?

Answer 13

Sensory: Face, cornea

Motor: Temporal and masseter muscles

• CN V: Trigeminal

Question 14

What does CN VII do?

Answer 14

Facial Expression

• CN VII: Facial

Question 15

What does CN VIII do?

Answer 15

Vestibular function

Test eye-head coordination, VOR

Cochlear function

• CN VIII: Vestibulocochlear

Question 16

What do CN IX & X do?

Answer 16

Phonation (voice quality)

Swallowing

Palatal, pharynx control

Gag Reflex

• CN IX: Glossopharyngeal
• CN X: Vagus

Question 17

What does CN XI do?

Answer 17

Trap and SCM muscle function

• CN XI: Accessory nerve

Question 18

What does CN XII do?

Answer 18

Tongue movements

• CN XII: Hypoglossal

Question 19

What is a dermatome?

Answer 19

specific segmental skin area innervated by sensory spinal axons

Question 20

What is a myotome?

Answer 20

skeletal muscles innervated by motor axons in a given spinal root

Question 21

In the cervical spine, do numbered roots exit above or below the corresponding vertebral body?

Answer 21

Above

(C8 nerve root exits below C7 vertebral body)

Question 22

In the thoracic, lumbar and sacral spine, do numbered roots exit above or below the corresponding vertebral body?

Answer 22

Below

Question 23

At what level does the spinal cord end?

Answer 23

L1

Question 24

What are the nerve roots called in the lumbosacral region?

Answer 24

Cauda Equina

Question 25

What is the function of the stretch reflex?

Answer 25

Stimulus: Muscle Stretch * Maintenance of muscle tone * Support agonist muscle contraction * Provide feedback about muscle length

Question 26

What is reciprocal inhibition?

Answer 26

stretch stimulus inhibits antagonist muscle

Question 27

What is reciprocal innervation?

Answer 27

Stretch stimulus on agonist (autogenic facilitation), antagonist (reciprocal inhibition), and synergistic muscles (facilitation).

Question 28

What is the function of the inverse stretch reflex?

Answer 28

Stimulus Muscle contraction * Provide agonist inhibition * Diminution of force of agonist contraction * Stretch-protect reflex

Question 29

What is the function of the Gamma Reflex loop?

Answer 29

Allows muscle tension to come under control of descending pathways (reticulospinal, vestibulospinal, and others)

Question 30

What is the function of the flexor withdrawal reflex?

Answer 30

Stimulus: Cutaneous sensory stimuli * Protective withdrawal mechanism to remove body part from harmful stimuli

Question 31

What is the function of the crossed extension reflex?

Answer 31

Stimulus: Noxious stimuli and reciprocal action of antagonists * Flexors excited on one side cause other side to inhibit * Coordinates reciprocal limb activities such as gait

Question 32

What spinal level does deep tendon reflexing testing test at the: Biceps tendon

Answer 32

C5-C6

Question 33

What spinal level does deep tendon reflexing testing test at the: Brachioradialis tendon

Answer 33

C5-C6

Question 34

What spinal level does deep tendon reflexing testing test at the: Triceps tendon

Answer 34

C6-C7

Question 35

What spinal level does deep tendon reflexing testing test at the: Patellar tendon

Answer 35

L3-L4

Question 36

What spinal level does deep tendon reflexing testing test at the: Achilles tendon

Answer 36

S1-S2