The Brain Stem

Question 1

principle functions of the Brain Stem

Answer 1

relay/ conduit
integration & regulation of sensory info
cranial nerve origin & termination

Question 2

rostral limit of brain stem

Answer 2

midbrain-diencephalon junction, below optic tracts

Question 3

Cerebral Peduncle

Answer 3

links brainstem to thalamus/cortex

contains ascending/descending tracts

Question 4

Crus Cerebri

Answer 4

location of motor tracts in cerebral peduncles

Question 5

Tectum

Answer 5

superior/inferior colliculi - “roof” of midbrain

Question 6

Tegmentum

Answer 6

“floor” of midbrain

contains red nucleus and substantia nigra

Question 7

Red Nucleus

Answer 7

motor coordination and fine hand movement

origin of rubrospinal extra-pyramidal descending motor tract

Question 8

Periaqueductal Gray

Answer 8

receives pain/temp info from lateral spinothalamic ascending tract
(gray matter in tegmentum)

Question 9

Superior Cerebellar Peduncles

Answer 9

connects to midbrain

carries Anterior Spinocerebellar tracts

Question 10

Middle Cerebellar Peduncles

Answer 10

connects to pons contralaterally

brain tracts

Question 11

Inferior Cerebellar Peduncles

Answer 11

connects to medulla

posterior and cuneocerebellar tracts

Question 12

Superior Colliculi

Answer 12

vision

Question 13

Inferior Colliculi

Answer 13

sound

Question 14

Gracile and Cuneate Fasciculus

Answer 14

Dorsal Columns of DCML ascending tract
synapse on second order neurons in medulla
decussate and forms medial lemniscus

Question 15

Cerebral Peduncles (location)

Answer 15

ventral surface

only midbrain

Question 16

Cerebellar peduncles

Answer 16

dorsal surface

all levels

Question 17

Pyramids

Answer 17

pyramidal tracts descending from motor cortex

Question 18

Olives

Answer 18

relay sensory and motor info

Question 19

Inferior Olives

Answer 19

cerebellar motor learning

Question 20

Pontine Nuclei function

Answer 20

allows unconscious modification of motor actions and error correction

Question 21

Pontine Nuclei pathway

Answer 21

receives info from ipsilateral primary motor cortex –> relays info to contralateral cerebellum

Question 22

Dorsal Column Medial Lemniscus - Cuneate Fasciculus

Answer 22

Discriminative touch, joint position, vibration, pressure of UPPER BODY

Question 23

Dorsal Column Medial Lemniscus - Gracile Fasciculus

Answer 23

Discriminative touch, joint position, vibration, pressure of LOWER BODY

Question 24

Decussation of DCML tracts

Answer 24

DCML tracts decussate in the medulla from the dorsal columns into the medial lemniscus to travel to thalamus

Question 25

Spinothalamic tracts (lateral vs anterior)

Answer 25

lateral: pain & temp anterior: light touch & pressure

Question 26

Spinocerebellar tracts (3)

Answer 26

Posterior Spinocerebellar tract Cuneocerebellar tract Anterior Spinocerebellar tract

Question 27

Posterior Spinocerebellar tract

Answer 27

lower body stays ipsilateral enters cerebellum through inferior cerebellar peduncles

Question 28

Cuneocerebellar tract

Answer 28

upper body stays ipsilateral enters cerebellum through inferior cerebellar peduncles

Question 29

Anterior Spinocerebellar tract

Answer 29

lower body decussates twice enters cerebellum through superior cerebellar peduncles

Question 30

Descending Tracts (2)

Answer 30

Corticospinal tract | Reticulospinal tract

Question 31

Reticular Formation function

Answer 31

modulates pain info from lateral spinothalamic tracts, | muscle tone, reflexes, motor control, and autonomic functions (eg respiration)

Question 32

Ascending Reticular Activating System (RAS) function

Answer 32

functions in arousal/consciousness by sending continuous input to cortex acts as filter to dampen repetitive, familiar or weak sensory input activity (about 99% of stimuli regarded as unimportant)

Question 33

Reticular Formation location

Answer 33

located in tegmentum axonal projections from cerebrum --> brainstem includes RAS and descending pathways via reticulospinal tracts

Question 34

Reticular Formation descending motor neurons

Answer 34

maintain skeletal muscle tone, balance and posture