Chapter 26: Trigeminal Nerve

Question 1

The Vth cranial nerve is called the trigeminal nerve because it has _____ major divisions.

Answer 1

• 3

Question 2

The superior division is called the ophthalmic nerve because it is the sensory nerve of the _____ socket and the skin above it.

Answer 2

• Eye

Question 3

The middle division of the trigeminal nerve is called the maxillary nerve because it is the sensory nerve of the area of the face overlying the _____ bone.

Answer 3

• Maxillary

Question 4

The ophthalmic and maxillary nerves are divisions of the _____ or _____ cranial nerve.

Answer 4

• Trigeminal

- Vth

Question 5

The _____ nerve is the sensory nerve of the upper third of the face and the _____ nerve is the sensory nerve of the middle third of the face.

Answer 5

• Ophthalmic

- Maxillary

Question 6

The ophthalmic and maxillary nerves are purely sensory and have no _____ component.

Answer 6

• Motor

Question 7

The lowest division of the trigeminal nerve is called the mandibular nerve because it is the sensory nerve of the region around the _____.

Answer 7

• Mandible

Question 8

The three divisions of the trigeminal nerve are the _____, _____, and _____ nerves.

Answer 8

• Ophthalmic
• Maxillary
• Mandibular

Question 9

Unlike the _____ and _____ nerves, the mandibular nerve has a significant motor component.

Answer 9

• Ophthalmic

- Maxillary

Question 10

The motor fibers in the _____ nerve innervate the muscles that move the mandible.

Answer 10

• Mandibular

Question 11

The temporalis and masseter, which close the mouth, the mylohyoid and anterior belly of the digastric, which open the mouth, and the medial and lateral pterygoid muscles, which move the jaw from side to side, are all innervated by the _____ nerve.

Answer 11

• Mandibular

Question 12

Although it assists with chewing, the buccinator muscle is not innervated by the mandibular nerve because it does not move the _____.

Answer 12

• Mandible

Question 13

The tensor tympani muscle is the only muscle innervated by the mandibular nerve that does not move the _____.

Answer 13

• Mandible

Question 14

A tiny branch of the mandibular nerve enters the middle ear through the wall of the Eustachian tube and innervates the _____ muscle.

Answer 14

• Tensor tympani

Question 15

Contraction of the tensor tympani makes it harder for the malleus to move and _____ sound.

Answer 15

• Deadens (muffles/attenuates)

Question 16

Reflex contraction of the tensor tympani during chewing _____ the _____ of chewing.

Answer 16

• Muffles

- Sound

Question 17

The motor fibers in the mandibular nerve are _____ of _____ neurons in the motor nucleus of the trigeminal nerve

Answer 17

• Axons

- Lower motor

Question 18

Although the sensory nuclei of the trigeminal nerve extend throughout the brainstem, the _____ nucleus is confined to the mid-pontine level.

Answer 18

• Motor

Question 19

The motor nucleus of the trigeminal nerve is just medial to the principal sensory nucleus of the trigeminal nerve at the _____ level.

Answer 19

• Mid-pontine

Question 20

The principal sensory nucleus of the trigeminal is the most lateral nucleus in the brainstem at the _____ level.

Answer 20

• Mid-pontine

Question 21

Motor axons from the motor nucleus of the trigeminal nerve pass through the foramen ovale along with the sensory fibers of the _____ to innervate the tensor tympani and the muscles that move the mandible.

Answer 21

• Mandibular nerve

Question 22

The motor division of the trigeminal nerve also contains muscle and tendon stretch fibers that are peripheral branches of axons of primary _____ neurons in the upper pons and midbrain.

Answer 22

• Sensory

Question 23

The muscle and tendon stretch neurons for the jaw muscles are in the _____ and _____.

Answer 23

• Upper pons

- Midbrain

Question 24

The primary sensory neurons for muscle and tendon stretch in the jaw muscles are collectively called the mesencephalic nucleus of the trigeminal nerve because most of them are in the _____.

Answer 24

• Midbrain (mesencephalon)

Question 25

The mesencephalic nucleus of the trigeminal nerve extends throughout the _____ and midbrain.

Answer 25

- Upper pons

Question 26

The _____ of the trigeminal nerve contains the primary sensory neurons for in jaw muscles and their tendons and the periodontal ligament.

Answer 26

- Mesencephalic

Question 27

The peripheral branches of the axons of neurons in the mesencephalic nucleus of the trigeminal nerve innervate muscle spindles and Golgi tendon organs in the _____ and corpuscles of Ruffini in the _____.

Answer 27

- Jaw muscles | - Periodontal ligament

Question 28

The _____ of the _____ is the only place where primary sensory neurons are found in the central nervous system.

Answer 28

- Mesencephalic nucleus | - Trigeminal nerve

Question 29

The mesencephalic nucleus of the trigeminal contains only _____ sensory neurons for muscle, tendon, and ligament stretch in the chewing apparatus.

Answer 29

- Primary

Question 30

The peripheral branches of the axons of the _____ neurons in the mesencephalic nucleus of the trigeminal nerve descend in the mesencephalic tract of the trigeminal nerve.

Answer 30

- Primary sensory

Question 31

The myelinated peripheral branches of axons of neurons in the mesencephalic nucleus of the trigeminal nerve form the _____ of the _____ lateral to the mesencephalic nucleus.

Answer 31

- Mesencephalic tract | - Trigeminal nerve

Question 32

Most central branches of the axons of the _____ and _____ neurons in the mesencephalic nucleus of the trigeminal nerve end in the motor nucleus of the trigeminal nerve.

Answer 32

- Muscle | - Tendon stretch

Question 33

The neurons in the mesencephalic nucleus of the trigeminal nerve are responsible for the muscle and tendon stretch reflexes in the _____.

Answer 33

- Jaw muscles

Question 34

Central branches of neurons in the _____ of the _____ that detect stretch in the periodontal ligament synapse on internuncial neurons that inhibit lower motor neurons for jaw muscles.

Answer 34

- Mesencephalic nucleus | - Trigeminal

Question 35

A few central branches of axons of neurons in the mesencephalic nucleus of the trigeminal nerve ascend in the opposite side of the _____ and end in the thalamus

Answer 35

- Mesencephalic tract

Question 36

Muscle and tendon stretch sensation from the right side of the head synapses in the _____ side of the _____.

Answer 36

- Left (contralateral) | - Thalamus

Question 37

The mesencephalic nucleus of the trigeminal nerve projects downward to the ipsilateral _____ of the _____ and the ipsilateral _____.

Answer 37

- Motor nucleus - Trigeminal nerve -

Question 38

The mesencephalic nucleus of the trigeminal nerve projects upward to the _____ side of the _____.

Answer 38

- Contralateral | - Thalamus

Question 39

Except for the muscle, tendon, and ligament stretch neurons in the _____, all primary sensory neurons of the trigeminal nerve are in the trigeminal ganglion.

Answer 39

- Mesencephalic nucleus

Question 40

Peripheral processes of the axons of neurons in the trigeminal ganglion are distributed to the upper, middle, and lower thirds of the face in the _____, _____, and _____ nerves.

Answer 40

- Ophthalmic - Maxillary - Mandibular

Question 41

The protopathic and epicritic nerves of the face are peripheral branches of axons of neurons in the ______.

Answer 41

- Trigeminal ganglion

Question 42

The corpuscles of Ruffini that replace muscle spindles as _____ detectors in the muscles of facial expression are innervated by neurons in the trigeminal ganglion.

Answer 42

- Stretch

Question 43

The muscles of facial expression get their motor innervation via the _____ and their sensory innervation via the _____.

Answer 43

- Facial nerve | - Trigeminal nerve

Question 44

Central processes of the axons of neurons in the _____ enter the lateral side of the middle of the pons as the sensory root of the trigeminal nerve.

Answer 44

- Trigeminal ganglion

Question 45

Central processes of axons of neurons for the epicritic senses of _____, _____, and _____ in the face synapse in the principal sensory nucleus of the trigeminal nerve.

Answer 45

- Discriminative touch - Pressure - Vibration

Question 46

Central processes of axons of epicritic neurons for the face synapse on internuncial neurons in the _____ of the _____ just lateral to the motor nucleus.

Answer 46

- Principal sensory nucleus | - Trigeminal nerve

Question 47

The principal sensory nucleus of the trigeminal nerve is at the mid-pontine level, _____ to the motor nucleus.

Answer 47

- Lateral

Question 48

_____ senses synapse in the principal sensory nucleus of the trigeminal nerve, _____ senses do not.

Answer 48

- Epicritic | - Protopathic

Question 49

The motor nucleus of the trigeminal nerve is _____ to the principal sensory nucleus and ventral (or anterior) to the mesencephalic nucleus at the mid pontine level.

Answer 49

- Medial

Question 50

Internuncial neurons in the _____ of the trigeminal nerve relay epicritic information from the _____ to both sides of the thalamus.

Answer 50

- Principal sensory nucleus | - Face (head)

Question 51

Epicritic information from the face is unusual in that is received by _____ of the thalamus.

Answer 51

- Both sides

Question 52

The _____ of the trigeminal nerve projects to the ipsilateral side of the _____ through the dorsal trigeminothalamic tracts.

Answer 52

- Principal sensory nucleus | - Thalamus

Question 53

The principal sensory nucleus of the trigeminal nerve projects to the _____ side of the thalamus through the ventral trigeminothalamic tract.

Answer 53

- Contralateral

Question 54

Each side of the thalamus receives epicritic sensations from the _____ side of the face through the dorsal trigeminothalamic tract and epicritic sensations from the _____ side of the face from the ventral trigeminothalamic tract.

Answer 54

- Ipsilateral | - Contralateral

Question 55

The _____ trigeminothalamic tract crosses in the pons, but the _____ trigeminothalamic tract does not cross.

Answer 55

- Ventral | - Dorsal

Question 56

The _____ is made up of crossed fibers that travel toward the thalamus along the dorsal side of the medial lemniscus.

Answer 56

- Ventral trigeminothalamic tract

Question 57

The ventral trigeminothalamic tract is often called the trigeminal lemniscus because of its proximity to the _____ and the similarity of their functions.

Answer 57

- Medial lemniscus

Question 58

The dorsal trigeminothalamic tract is made up of _____ fibers that travel toward the thalamus along the dorsal side of the central tegmental tract.

Answer 58

- Uncrossed

Question 59

The _____ carries epicritic sensations from the contralateral side of the face, and the _____ carries epicritic sensations from the ipsilateral side of the face

Answer 59

- Ventral trigeminothalamic tract | - Dorsal trigeminothalamic tract

Question 60

Primary sensory neurons for the protopathic senses of _____, _____, and _____ in the face are in the _____.

Answer 60

- Pain - Temperature - Vague touch - Trigeminal ganglion

Question 61

Central processes of the axons of protopathic neurons in the trigeminal ganglion enter the pons in the _____ and descend through the lower pons and medulla as the spinal tract of the trigeminal nerve.

Answer 61

- Trigeminal nerve

Question 62

Central processes of the axons of protopathic neurons in the trigeminal ganglion form the _____ of the _____.

Answer 62

- Spinal tract | - Trigeminal nerve

Question 63

Fibers in the spinal tract of the trigeminal nerve descend in the _____ and synapse in the "spinal nucleus" of the trigeminal nerve medial to the spinal tract.

Answer 63

- Lower pons/medulla

Question 64

Pain and light touch in the cornea makes its first synapse in the _____ of the _____.

Answer 64

- Spinal nucleus | - Trigeminal nerve

Question 65

The spinal nucleus of the trigeminal nerve is _____ to the spinal tract of the trigeminal nerve.

Answer 65

- Medial

Question 66

The spinal tract of the trigeminal nerve carries only _____ sensations.

Answer 66

- Protopathic

Question 67

The afferent limb of the corneal reflex is in the _____; the efferent (effector) limb is in the _____.

Answer 67

- Trigeminal nerve (and spinal tract) | - Facial nerve

Question 68

The spinal nucleus of the trigeminal nerve gets its name from the fact that it extends from the mid-pontine level to the uppermost _____ level.

Answer 68

- Cervical

Question 69

The spinal tract of the trigeminal nerve also extends from the _____ level to the C1 level.

Answer 69

- Mid-pontine

Question 70

The spinal tract of the trigeminal nerve is _____ to the spinal nucleus of the trigeminal nerve.

Answer 70

- Lateral

Question 71

The first cervical nerve often has no sensory root because the posterior horn region of the spinal cord at the C1 level is occupied by the _____ of the _____.

Answer 71

- Spinal nucleus | - Trigeminal nerve

Question 72

Protopathic sensations in the face make their first synapse in the _____ of the _____.

Answer 72

- Spinal nucleus | - Trigeminal nerve

Question 73

The spinal nucleus of the trigeminal nerve relays _____ sensations from the face to the contralateral side of the thalamus.

Answer 73

- Protopathic

Question 74

The thalamus receives _____ information from both sides of the face but receives _____ information only from the opposite side.

Answer 74

- Epicritic | - Protopathic

Question 75

The _____ nucleus and the _____ nucleus of V are at the mid-pontine level; the _____ nucleus is caudal to them, and the _____ nucleus is rostral to them.

Answer 75

- Motor - Principal sensory - Spinal - Mesencephalic

Question 76

The motor nucleus of V contains _____ neurons for the _____ muscles.

Answer 76

- Lower motor | - Jaw (chewing)

Question 77

The principal sensory nucleus of V contains _____ order neurons for _____ senses.

Answer 77

- Second | - Epicritic

Question 78

The principal sensory nucleus of V projects to the ipsilateral side of the thalamus via the _____.

Answer 78

- Dorsal (posterior) trigeminothalamic tract

Question 79

The principal sensory nucleus of V projects to the contralateral side of the thalamus via the _____.

Answer 79

- Ventral (anterior) trigeminothalamic tract

Question 80

The spinal nucleus of the trigeminal contains _____ order neurons for _____ senses.

Answer 80

- Second | - Protopathic

Question 81

The spinal nucleus of the trigeminal projects to the _____ side of the thalamus via the _____.

Answer 81

- Contralateral | - Ventral trigeminothalamic tract

Question 82

The mesencephalic nucleus of the trigeminal contains _____ order neurons for _____.

Answer 82

- First | - Stretch