H&n A8: Brainstem Lecture 8

Front 1

What is the function of the brainstem?

Back 1

Site of beginning of motor axons, termination of sensory axons

Front 2

How many cranial nerves have motor fibers that either originate in brainstem nuclei and/or have sensory fibers that carry impulses that terminate in the nuclei brainstem? Which ones bypass the brainstem, and where do they go?

Back 2

10. CN I (olfactory, smell) goes directly to frontal lobe, and CN II (optic nerve) -> optic chiasm -> lateral geniculate body (thalamus) -> superior colliculus (midbrain)

Front 3

10 of the 11 cranial nerves exit on the __ side of the brainstem. Which one exits on the other side?

Back 3

ventral. Cranial nerve IV (trochlear) exits from dorsal side.

Front 4

What large structures on the ventral aspect of the brainstem are clearly visible? What are their functions?

Back 4

Cerebral peduncle - motor axons from brainstem -> spinal cord

Inferior olive - coordinate movement of eyes with musculature of the head

Pyramidal decussation - motor fibers from the lateral corticospinal and rubrospinal tract cross here

Front 5

Are mammillary bodies/the infundibulum part of the brainstem?

Back 5

No, they're part of the hypothalamus but often adhere to the brainstem.

Front 6

What are prominent features on the dorsal aspect of the brainstem? What is the function of each?

Back 6

Superior colliculus - sight/movement of eyes.

Inferior colliculus - hearing.

Superior/middle/inferior cerebellar peduncles - pathway from brainstem -> cerebellum

Fasciculus gracilis and fasciculus cuneatus to nuclei in the medulla.

3rd ventricle, cerebellum, medulla

THALAMUS: lateral geniculate nucleus (sight, optic nerve runs here)

Meidal geniculate nucleus (hearing)

Pineal gland - regulation of circadian rhythms

Front 7

Where does the trochlear nerve exit?

Back 7

On the dorsal side of the brainstem, below the inferior colliculus.

Front 8

What are the three white matter pathways that you can see traveling between the brainstem and cerebrum?

Back 8

Superior, inferior, and middle cerebellar peduncles.

Front 9

Where is the third ventricle located?

Back 9

Superior to the midbrain.

Front 10

What wraps around the fourth ventricle?

Back 10

Medulla and cerebellum.

Front 11

What are the medial and lateral geniculate nuclei a part of? What are their functions?

Back 11

Thalamus.

Medial - hearing

Lateral - sight

Front 12

Where does the trigeminal sensory nucleus stretch from?

Back 12

Brainstem to third cervical segment of the spinal cord.

Front 13

What are functions associated with the midbrain?

What nuclei are found in the midbrain?

Back 13

Vision, pupillary constriction, coordination of eye movements with the upper portion fo the body (superior colliculus), hearing (inferior)

TOE:
Trochlear nucleus (somatic motor
Oculomotor (somatic motor)
Edinger Westphal (visceral motor)

Front 14

What are the functions associated with the pons?

What nuclei are found in the pons?

Back 14

Motor functions, sensory functions, consciousness, sleep.

FAST:

Facial motor nucleus (branchial motor)
Abducens (somatic motor)
Superior salivatory nucleus (visceral motor)
Trigeminal motor nucleus (branchial motor)

Front 15

What are functions associated with the medulla?

What nuclei are found in the medulla?

Back 15

Motor/sensory control, control of breathing and heart rate.

SHIND:

Solitary nucleus (visceral sensory)
Hypoglossal nucleus (somatic motor)
Inferior salivatory nucleus (visceral motor)
Nucleus ambiguus (branchial motor)
Dorsal motor nucleus of X (visceral motor)

Front 16

SOMATIC SENSORY:

1) Which cranial nerves carry it?
2) Where do these nerves terminate?
3) Where is the nucleus found?

Back 16

1) CN 5, 7, 9, 10
2) Trigeminal sensory nucleus
3) Throughout the brainstem

Front 17

VISCERAL SENSORY:

1) What cranial nerves carry it?
2) Where do they terminate?
3) Where is the nucleus located?

Back 17

1) 7, 9, 10
2) Solitary nucleus
3) Medulla

Front 18

Fibers from the oculomotor nucleus:

1) What kind of modality is it?
2) Where is the nucleus located?
3) What do the fibers travel on?

Back 18

1) Somatic motor
2) Midbrain
3) 4 of 6 extraocular muscles (superior, inferior, & middle rectus, inferior oblique), levator palpebrae superioris muscle.

Front 19

Fibers from the trochlear nucleus:

1) What kind modality is it?
2) Where is the nucleus located?
3) Where do the fibers travel to?

Back 19

1) Somatic motor
2) Midbrain
3) Superior oblique muscle

Front 20

Fibers from the abducens nucleus:

1) What kind of modality is it?
2) Where is the nucleus located?
3) Where do the fibers travel to?

Back 20

1) Somatic motor
2) Pons
3) Lateral rectus muscle

Front 21

Fibers from the hypoglossal nucleus:

1) What kind modality is it?
2) Where is the nucleus located?
3) Where do the fibers travel to?

Back 21

1) Somatic motor
2) Medulla
3) Extrinsic and intrinsic muscles of the tongue

Front 22

Fibers from the Edinger-Westphal nucleus:

1) What kind modality is it?
2) Where is the nucleus located?
3) What nerve does it travel in and where does it synapse? What muscles do postganglionic fibers travel to?

Back 22

1) Visceral motor
2) Midbrain
3) Oculomotor nerve, ciliary ganglion-> Ciliary muscles/constrictor pupillae

Front 23

Fibers from the superior salivatory nucleus:

1) What kind of modality is this?
2) Where is the nucleus located?
3) What nerve does it travel in and where does it synapse?
4) What muscles do postganglionic fibers travel to?

Back 23

1) Visceral motor
2) Caudal aspect of pons
3) Facial nerve, pterygopalatine ganglion/submandibular ganglion
4) Pterygopalatine ganglion -> mucus glands/lacrimal gland. Submandibular ganglion -> submandibular/sublingual/smaller salivary glands in tongue/oral cavity.

Front 24

Fibers from the inferior salivatory nucleus:

1) What kind of modality is this?
2) Where is the nucleus located?
3) What nerve does it travel in and where does it synapse and what muscles do postganglionic fibers travel to?

Back 24

1) Visceral motor
2) Rostral aspect of medulla
3) Glossopharyngeal nerve, otic ganglion -> parotid salivary gland

Front 25

Fibers from the dorsal motor nucleus of X:

1) What modality is this?
2) Where is the nucleus located?
3) What nerve does it travel in, where does it synapse?

Back 25

1) Visceral motor
2) Medulla
3) Vagus nerve, ganglia in thorax and abdomen, up to midpoint of transverse colon

Front 26

Fibers from the trigeminal motor nucleus:

1) Where is the nucleus located?
2) What modality is this?
3) What nerve does it travel in and what does it innervate?

Back 26

1) Midpons
2) Branchial motor
3) Trigeminal nerve. Muscles of mastication (masseter, temporalis, lateral and medial pterygoids, anterior and posterior digastric, mylohyoid, tensor tympani and tensor veli palatini

Front 27

Fibers from the facial motor nucleus

1) What modality is this?
2) Where is the nucleus located?
3) What nerve does it travel in and what muscles does this innervate?

Back 27

1) Branchail motor
2) Pons
3) Facial nerve/muscles of facial expression, stylohyoid and stapedius

Front 28

Fibers from the nucleus ambiguus:

1) What modality is this?
2) Where is the nucleus found?
3) What cranial nerves does it travel in, and muscles does it innervate?

Back 28

1) Branchial motor
2) Medulla
3) 3 cranial nerves:

Glossopharyngeal - >stylopharyngeus

Vagus -> larynx and pharynx

Accessory nerve -> sternocleidomastoid (helps you lower your head) and trapezius (helps you elevate your shoulder, muscles in the back).

Front 29

What embryologic layer does the nervous system develop from? What do the CNS and PNS develop from?

Back 29

Ectoderm.

CNS from tissue around neural tube
PNS from tissue of the neural crest

Front 30

What cells produce CSF and where are these cells found?

Back 30

Choroid cells, in the central canal.

Front 31

What cells comprise the actual structure of a ventricle?

Back 31

Ependymal cells.

Front 32

As a general rule, where are motor nuclei found in the brainstem? Sensory?

Back 32

Motor in middle, sensory in periphery of brainstem.

Front 33

Medulla at the pyramidal decussation:

1) What areas can be seen?
2) What happens to the pyramidal fibers here?

Back 33

Brainstem and spinal cord areas, because it's the extreme caudal aspect of the brainstem.

90% decussate and continue as lateral corticospinal tract. Fibers of anterior corticospinal tract decussate at level of the section where they will synapse on contralateral ventral horn cells.

Front 34

Medulla at the decussation of the medial lemniscus:

1) What happens here?
2) What nuclei are visible here?

Back 34

1. Fibers from nucleus gracilis and nucleus cuneatus cross from one side fo the brainstem in the medial lemniscus to the contralateral thalamus.

2. Dorsal motor nucleus of X, hypoglossal nucleus

Front 35

What parts of the brainstem are the mesencephalic nucleus and tract of V found?

Back 35

Caudal aspect of midbrain, rostral portion of pons (you will see them in both slides)

Front 36

What are the primary tracts that make up pyramidal fibers? Where do they originate and where do they go?

Back 36

Collectively, called the corticobulbar tract. They are the corticomesencephalic, corticomedullary, corticospinal tracts. Originate in motor/premotor cortices of cerebrum, terminate on motor nuclei of the brain.

Front 37

What synapses in the red nucleus?

Back 37

Fibers from the cerebellum and basal ganglia.

Front 38

What tract is formed from the fibers of the red nucleus?

Back 38

Rubrospinal tract.

Front 39

Why are the Edinger-Westphal nucleus and oculomotor nucles adjacent to each other in the midbrain?

Back 39

Because fibers from both run with each other in the oculomotor nerve.

Front 40

What do cells in the substantia nigra produce? What does this substance travel to?

Back 40

Dopamine, which travels through axons to basal ganglia and other structures in the brainstem.

Front 41

What is another name for crus cerebri? What is it?

Back 41

Cerebral peduncle, collection of pyramidal fibers.

Front 42

What is the infundibulum?

Back 42

Structure where the pituitary stalk comes down.

Front 43

Why does cranial nerve V look like it exits the brainstem and splits?

Back 43

Because it splits into huge motor portion and huge sensory portion.

Front 44

What nerves are lateral to the pontomedullary junction? What units can these nerves split into?

Back 44

6, 7, 8.

7 - split into big motor and sensory units.

8 - Splits into balance and hearing parts.

Front 45

What nerves are lateral to the inferior olive?

Back 45

9, 10, 11

Front 46

No matter where it is, brainstem injuries will always affect what nucleus?

Back 46

Trigeminal nucleus.

Front 47

Person has a stroke that involves the brainstem. Person's talking hoarsely, having problems swallowing, and having problems lifting shoulder on one side. What part of the brainstem is affected?

Back 47

Medulla.

Front 48

Person's pupil on one side is abnormally dilated compared to the other. On one side, person is having problems moving his eye. What part of the brainstem is involved?

Back 48

Stroke involves midbrain because of the oculomotor nucleus or the Edinger Westphal nucleus, which constrict pupil.

Front 49

What are the six possible modalities in cranial nerves? Do any cranial nerves contain all six modalities?

Back 49

1) Somatic motor
2) Visceral motor
3) Somatic sensory
4) Visceral sensory
5) Special efferent (branchial motor)
6) Special sensory (sight, smell, hearing, balance, taste)

No, but 3 of the cranial nerves have 5 of these modalities. None have 6.

Front 50

Where do olfactory senses go to in the brain?

Back 50

Olfactory bulb and then frontal lobe of the cerebrum. Nothing to do with the brainstem.

Front 51

Does the optic nerve send information DIRECTLY back to the brainstem? Describe its path.

Back 51

NO. Optic nerve -> optic chiasm -> lateral geniculate body (thalamus) -> superior colliculus (midbrain).

Front 52

Name the 6 muscles that move the eye, what they do, and what nerves they're associated with.

Back 52

1) Superior rectus - moves eyeball superiorly (CN III)
2) Medial rectus - CN III
3) Inferior rectus - moves eyeball down (CN III)
4) Lateral rectus - CN VI
5) Superior oblique - moves eyeball INFERIORLY - CN IV (trochlear)
6) Inferior oblique - moves eyeball SUPERIORLY - CN III

Front 53

What does the levator palpebrae superiorus do? What cranial nerve is it associated with?

Back 53

Elevates eyelid - CN III

Front 54

What are the two nuclei associated with the oculomotor nerve? What muscles do they affect?

Back 54

Edinger-Westphal (visceral motor) - constrictor pupillae, ciliary muscles. Oculomotor nucleus (somatic motor) - superior, inferior, middle rectus, inferior oblique.

Front 55

If the left oculomotor nerve is damaged and you look at the person's eyeball, you should be know that immediately. How?

Back 55

#1: eye is going to be laterally deviated, because lateral rectus will still be working because the medial rectus will not. Lateral rectus is powered by a separate nerve - the abducens nerve.

Front 56

Occipital somites end up differentiating into 4 groups of muscles. What are these muscles?

Back 56

1) Oculomotor
2) Trochlear
3) Abducens
4) Hypoglossal

Looks like occipital somites differentiate into somatic motor

Front 57

What muscles do the motor nucleus of V control?

Back 57

Branchial motor to muscles of mastication:

1) Masseter
2) Temporalis
3) Lateral pterygoids
4) Medial pterygoids

also anterior digastric, posterior digastric, tensor tympani (regulates tympanic membrane so it doesn't vibrate on its own), and tensor veli palatini (tenses the palate correctly so you can swallow)

Front 58

The vestibulocochlear system is associated with which part of the brainstem?

Back 58

Both pons and medulla, because the nucleus is in both parts

Front 59

List the five modalities that the facial nerve carries, and what muscles they interact with specifically.

Back 59

1) Taste - anterior 2/3 of tongue (SOLITARY NUCLEUS)
2) Visceral motor - lacrimal, submandibular, nasal, pharyngeal glands (superior salivatory nucleus)
3) Visceral sensory - glands, blood vessels (solitary nucleus)
4) Somatic sensory - external ear (pontine and spinal trigeminal)
5) Branchial motor - muscles of facial expression, stapedius, stylohyoid (facial motor nucleus)

Front 60

List the five modalities that the glossopharyngeal nerve carries, and what muscles they interact with specifically.

Back 60

1) Taste - posterior 1/3 tongue (solitary nucleus)
2) Visceral motor - parotid gland (inferior salivatory)
3) Visceral sensory - glands, blood vessels, carotid body (solitary)
4) Somatic sensory - external ear (pontine and trigeminal nucleus)
5) Branchial motor - stylopharyngeus (nucleus ambiguus)

Front 61

List the five modalities that the vagus carries, and what muscles they interact with specifically.

Back 61

1) Taste - area adjacent to epiglottis (solitary nucleus)
2) Visceral motor - fibers in thorax, abdomen to midpoint of transverse colon (dorsal motor nucleus of X)
3) Visceral sensory - areas innervated by motor fibers (solitary)
4) Somatic sensory - external ear (pontine and spinal trigeminal)
5) Branchial motor - muscles of pharynx and larynx (nucleus ambiguus)

Front 62

If the anterior 2/3 of the tongue couldn't taste, what could be the problem? How can you tell what the problem is?

Back 62

Problem with either facial nerve, or the solitary nucleus itself.

To test facial nerve - look at muscles of facial expression.

To test if it's CNS, test taste on posterior 1/3 of the tongue. If there's no taste there, it's a problem with a solitary nucleus.

Front 63

Patient has no taste on the right side of his tongue. What could be the possible factors?

Back 63

1) tongue is damaged
2) xerostomia
3) facial nerve damaged (test muscles of facial expression)
4) glossopharyngeal damage (he would also be swallowing and talking weird), hearing background noise
5) solitary nucleus in the medulla damaged

Front 64

What cranial nerves are involved in:

1) Taste
2) Visceral sensory
3) Somatic sensory
4) Branchial motor
5) General somatic afferent
6) General visceral afferent

Back 64

1) Taste - 7, 9, 10
2) Visceral sensory - 7, 9, 10
3) Somatic sensory - 7, 9, 10
4) Branchial motor - 5, x9, 10, 11
5) General somatic afferent - 5, 7, 9, 10
6) General visceral afferent - 7, 9, 10

Front 65

What are the five special afferent senses, what nerves do they travel in, and where do they end up?

Back 65

1) Smell (CN I) -> olfactory bulb -> frontal lobe of brain

2) Sight (CN II) -> optic nerve -> optic chiasm -> lateral geniculate body (thalamus) -> superior colliculus (midbrain)

3) Hearing (CN VIII) - cochlear nuclei in the medulla

4) Balance (CN VIII) - vestibular nuclei in medulla

5) Taste (CN VII, IX, X) - solitary nucleus in medulla

Front 66

Name the four cranial nerves involved with general somatic motor (efferent) modality and what nuclei they originate from

Back 66

Oculomotor (3), trochlear (4), abducens (6), hypoglossal (12)

III -> oculomotor nucleus in the midbrain

IV -> trochlear nucleus in midbrain

VI -> abducens nucleus in pons

XII -> hypoglossal nucleus in medulla

Front 67

Name the four nuclei involved with general visceral efferent and what cranial nerves they connect to.

Back 67

Edinger Westphal in midbrain -> III

Superior salivatory nucleus in pons -> VII

Inferior salivatory nucleus in medulla -> IX

Dorsal motor nucleus of X in the medulla -> X

Front 68

Name the three nuclei involved with branchial motor (efferent) and what cranial nerves they connect to.

Back 68

Trigeminal motor nucleus -> V

Facial motor nucleus in pons -> VII

Nucleus ambiguus in the medulla -> IX, X, XI

Front 69

Wallenberg's syndrome - lateral medullary syndrome. What is wiped out?

Back 69

Dental School Never End in Vain

Dorsal motor nucleus of X
Solitary nucleus
Nucleus ambiguus
External cuneate nucleus
Inferior cerebellar peduncle
Vestibular nuclei

Front 70

What is the only brain section where you can see two pyramidal tracts? Why is this happening?

Back 70

Upper pons. One of the sections is the corticopontine pyramidal tract division. The other is the corticomedullary/corticospinal tract.

Front 71

Does the oculomotor nerve supply muscles ipsilaterally or contralaterally?

Back 71

Supplies its muscles ipsilaterally.

Front 72

Does the crus cerebri supply muscles that are ipsilateral or contralateral?

Back 72

Contralateral.

Front 73

A tumor is damaging fibers of the oculomotor nerve and pyramidal tract. Where do you see symptoms?

Back 73

See oculomotor symptoms ipsilaterally, contralateral trouble with limbs. This is alternating hemiparesia (hemiplegia)

Front 74

TASTE:

1) What cranial nerves carry it?
2) What nucleus does it terminate on? Where is the nucleus?
3) What part of the midbrain is it associated with?

Back 74

1) 7, 9, 10
2) Solitary nucleus in the medulla
3) Pons and medulla because CN 7, 9, 10 are at the pontomedullary junction

Front 75

What two cranial nerves control salivary glands?

Back 75

Facial (superior salivatory nucleus - submandibular, sublingual, smaller glands in oral cavity/tongue)

Glossopharyngeal (inferior salivatory nucleus - parotid gland)

Front 76

Describe the pharyngeal plexus theory.

Back 76

Branchial motor fibers originating in the nucleus ambiguus can be found in both the vagus and accessory nerve. Some people think that fibers from teh accessory nerve leap onto major parts of the vagus nerve.

Front 77

What develops from the alar and basal plate?

What is the alar plate separated from the basal plate by?

Back 77

Alar - somatic and visceral sensory

Basal - somatic and visceral motor

Sulcus limitans

Front 78

Why is the medulla at the inferior olivary nucleus prone to damage?

What are prominent structures at this section?

Back 78

Because of the clogging of the posterior inferior cerebellar artery (Wallenberg's syndrome)

1) Inferior olivary nucleus (snake)
2) Pyramidal tract (nothing has crossed yet)
3) Medial lemniscus
4) Hypoglossal nucleus
5) Motor nucleus of X
6) Solitary nucleus and tract
7) Vestibular nuclei
8) External cuneate nucleus

Front 79

Nuclei associated with cranial nerve 3 are in what part of the brainstem?

Back 79

Midbrain, because the oculomotor nerve exits the midbrain.

(oculomotor and edinger-westphal)

Front 80

What is the dorsal root ganglion derived from embryologically?

Back 80

Neural crest

Front 81

What develops from the alar plate? Basal plate?

Back 81

Alar -> dorsal horn -> somatic and visceral sensory

Basal -> ventral horn -> visceral and somatic motor

Front 82

What are the three nerves involved with eye movement and what are their nuclei?

Back 82

Oculomotor - 1) oculomotor nucleus -> superior, inferior, lateral rectus, inferior oblique, levator palpebrae superioros 2) edinger westphal (vm) - -> ciliary ganglion, ciliary muscles and constrictor pupillae

Trochlear - trochlear nucleus - superior oblique

Abducens - abducens nucleus -> lateral rectus

Front 83

The accessory nerve carries what kind of modality?

What is the function of the sternocleidomastoid? Trapezius?

Back 83

Branchial motor.

Sternocleidomastoid - helps you lower your head. Trapezius - helps you elevate your shoulder, muscle in back.

Front 84

Which cranial nerves carry sensory from the earlobe?

Back 84

7, 9, 10

Front 85

What is the function of the stapedius? What controls it?

Back 85

Makes sure your muscles don't vibrate when there is no noise. Facial motor nucleus -> facial nerve.

Front 86

A person has trouble moving their tongue and their heartbeat is variable. Where is the damage?

Back 86

Hypoglossal nucleus, dorsal motor nucleus of X.

Front 87

A person is having problems with taste and their blood pressure is weird. What's affected?

Back 87

Solitary nucleus.

Front 88

Why does the red nucleus stain dark?

Back 88

Because there are so many axons leaving it.

Front 89

What does the carotid body do? What nerve sends sensory information from it back to the brain?

Back 89

Regulates blood pressure - glossopharyngeal, back to solitary nucleus.