NeuroAnatomy - Lecture Eight Objectives - Brainstem

Question 1

which cranial nerves do not emerge from the brainstem?

Answer 1

CN I & CN II

Question 2

which cranial nerves emerge from the midbrain of the brainstem?

Answer 2

CN III & CN IV

Question 3

which cranial nerves emerge from the pons of the brainstem?

Answer 3

CN V - CN VIII

Question 4

which cranial nerves emerge from the medulla of the brainstem?

Answer 4

CN IX - CN XII

Question 5

which cranial nerves can be viewed in the anterior view?

Answer 5

all of them

Question 6

which cranial nerves can be viewed in the posterior view?

Answer 6

CN IV is the only CN to emerge from posterior brainstem

Question 7

what structures are found within the external midbrain?

Answer 7

CN III & CN IV , cerebral peduncles, superior/inferior colliculus

Question 8

what structures are found within the internal midbrain?

Answer 8

cerebral aqueduct, periaqueductal gray area, CN III/CN IV nuclei, red nucleus, substantia nigra, descending motor tracts in peduncles

Question 9

what structures are found within the pons?

Answer 9

CN V - CN VIII , motor tracts that descend into anterior pons, 4th ventricle

Question 10

what structures are found within the medulla?

Answer 10

CN IX - CN XII , pyramids, pyramidal decussation

Question 11

what are the three vertical columns of the brainstem listed from anterior - posterior?

Answer 11

basis, tegmentum, tectum

Question 12

what structures are found within the tectum?

Answer 12

superior colliculus and inferior colliculus

Question 13

what is the function of the superior colliculus?

Answer 13

visual reflexes; pupillary light, looking away/towards stimuli

Question 14

what is the function of the inferior colliculus?

Answer 14

auditory reflexes

Question 15

what structures are found within the tegmentum?

Answer 15

reticular formations & ascending/descending somatosensory tracts

Question 16

what is the function of the ascending somatosensory tracts in the tegmentum?

Answer 16

proprioception, light touch, pain and temperature from the body and head

Question 17

what are the four descending motor tracts originating from BRAINSTEM NUCLEI?

Answer 17

rubrospinal tract, tectospinal tract, reticulospinal tract, and vestibulospinal tract

Question 18

where does the rubrospinal tract originate from?

Answer 18

red nucelus in midbrain

Question 19

where does the tectospinal tract originate from?

Answer 19

tectum in midbrain

Question 20

where does the reticulospinal tract originate from?

Answer 20

reticular nuclei in lower 2/3 of brainstem

Question 21

where does the vestibulospinal tract originate from?

Answer 21

vestibular nuclei in lower brainsteam

Question 22

what structures are found within the basis?

Answer 22

descending motor tracts that originate from cortex

Question 23

what are the three descending motor tracts originating from CORTEX?

Answer 23

corticospinal tract, corticobulbar tract, and corticopontine tract

Question 24

where does the corticospinal tract originate/descend to and does what function?

Answer 24

originates in the primary motor cortex, descends in basis of brainstem and continues down the spinal cord to supply muscles of the body

Question 25

where does the corticobulbar tract originate/descend to and does what function?

Answer 25

originates in the primary motor cortex, descends in basis of brainstem and connect to cranial nerves that supply muscles of the head

Question 26

where does the corticopontine tract originate/descend to and does what function?

Answer 26

descend from motor cortices, descends in basis of upper brainstem, terminates in pontine nuclei and connects to cerebellum

Question 27

what is reticular formation and where is it located?

Answer 27

a cluster of nuclei located in tegmentum throughout brainstem

Question 28

where is the rostral reticular formation?

Answer 28

upper pons/midbrain

Question 29

where is the caudal rectiular formation?

Answer 29

lower pons/medulla

Question 30

what does the reticular formation do?

Answer 30

regulates/modulates most CNS areas

Question 31

what is the function of CAUDAL reticular formation?

Answer 31

1. modulate respiratory/cardiovascular nuclei of brainstem 2. modulate motor functions & complex physiological motor reflexes 3. modulate nociception pathways (inhibits)

Question 32

what is the function of ROSTRAL reticular formation?

Answer 32

modulate consciousness // alertness, attention, awareness. Damage to upper brainstem results in potential coma or impaired consciousness

Question 33

what are the characteristics of a coma?

Answer 33

unconscious, no meaningful response to stimuli, low GS scores, CNS cells alive but significantly reduces metabolism, generally not permanent and will progress/digress after 2-4 weeks

Question 34

what areas are affected relating to comas?

Answer 34

severely depressed function of cortex and sub-cortical regions as well as rostral reticular formation

Question 35

what reflexes are still intact during comas?

Answer 35

spinal cord and brainstem reflexes

Question 36

what are the characteristics of a vegetative state?

Answer 36

similar to coma, GS score SLIGHTLY higher than coma, displays some sub-cortical function (i.e. sleep-wake cycle and some arousal reflexes)

Question 37

what areas are affected relating to vegetative states?

Answer 37

severely depressed function of cortex and sub-cortical regions

Question 38

what reflexes are still intact during vegetative states?

Answer 38

spinal cord and brainstem reflexes as well as some arousal reflexes (open eyes / turn towards stimuli, random sounds or movements, etc)

Question 39

what are the characteristics of brain death?

Answer 39

no evidence of cortex, diencephalon, and brainstem function including absent brainstem reflexes

Question 40

what areas are affected relating to brain death?

Answer 40

absent function of cortex, sub-cortical arousal system and brainstem

Question 41

what reflexes are still intact during brain death?

Answer 41

spinal cord

Question 42

what artery supplies the medulla?

Answer 42

small branches of vertebral artery supplies most of medulla and PICA supplies lateral medulla

Question 43

what artery supplies the pons?

Answer 43

small branches of pontine arteries supply most of pons and AICA/branches from VA supplies small lateral region of lower pons

Question 44

what artery supplies the midbrain?

Answer 44

PCA

Question 45

what artery is involved in Weber's Syndrome?

Answer 45

right or left PCA in midbrain

Question 46

what are the clinical findings of Weber's Syndrome?

Answer 46

contralateral hemiplegia/paresis, ipsilateral CNIII palsy, Parkinsonian if substantia nigra is affected

Question 47

what artery is involved in Pure Motor Hemiparesis?

Answer 47

right or left pontine arteries of basilar artery along left or right anterior pons

Question 48

what are the clinical findings of Pure Motor Hemiparesis?

Answer 48

contralateral hemiplegia/paresis

Question 49

what artery is involved in Locked-In Syndrome?

Answer 49

basilar artery // "bilateral stroke of anterior pons"

Question 50

what are the clinical findings of Locked-In Syndrome?

Answer 50

quadriplegia with intact sensation/cognition, all motor function is impaired EXCEPT for CNIII and possibly CNIV

Question 51

how does a coma vs. locked-in syndrome compare?

Answer 51

locked-in syndrome mimics a coma but the patient is conscious and may be able to communicate via eye blinking and is aware of their environment

Question 52

what artery is involved in Wallenberg Syndrome?

Answer 52

vertebral artery, PICA, or small branches of PICA // unilateral stroke of lateral medulla

Question 53

what are the clinical findings of Wallenberg Syndrome?

Answer 53

loss of pain/temp to ipsilateral face (CNV) , contralateral body // vertigo/nausea/vomit/nystagmus (CNVIII) , hoarseness/dysphagia (CNIX/CNX), ataxia