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Flashcards in Midbrain Deck (18):
1

1.2 Components of Tectum

Corpora Quadrigemina w/ superior and inferior colliculi

2

Superior vs. Inferior Colliculi

Vision and associate w/ lateral geniculate vs. hearing and associate w/ medial geniculate of thalamus

3

3 Large Visible Contents of Tegmentum

Cerebral peduncle
Substantia nigra
Red nucleus

4

Cerebral peduncle

Contains all corticospinal/pontine/bulbar descending motor fibers so contralateral. Also somatotropic

5

Substantia nigra

Lots of melanin deposited so it looks black, but spreads DA

6

14 Contents of Midbrain

III
Ventral tegmental area
Substantia nigra
Medial lemniscus
Superior colliculus and inferior
Periaqueductal gray
Trigeminothalamic tract
Cerebral aqueduct
Spinothalamic tract
Medial longitudinal fasiculus
Cerebral peduncle
Red nucleus
Trochlear nucleus

7

Ventral Tegmental Area (VTA)

Medial aspect of substantia nigra under peduncle. Also contains lots of DA but instead of going to basal ganglia spreads all throughout brain like Raphe or ceruleus

8

Periaqueductal Gray

Gray nuclei around cerebral aqueduct that do pain/autonomic and reticular area shit

9

Branchium

Arm of colliculi that head to geniculate

10

Pain Gating

Periaqueductal gray sends fibers to Raphe which send it to dorsal horn of spinal cord to modulate/override pain w/ descending signals

11

2 Arteries Around III

Superior cerebellar and posterior cerebral a.s, so they can compress it

12

3 Parasympathetic Effects of III

Pupillary constriction
Acommodation
Nucleus of Edinger-Westphal next to III nucleus, so lose one and you lose both

13

Different Levels of the Two CNs

III at level of superior colliculus and IV and level of inferior

14

Trochlear Nerve (IV) Path

Exits posterior and immediately crosses to innervate contralateral superior oblique muscle. So lesion nucleus its contralateral but nerve probably ipsi

15

3 Signs of III Lesion

Pupil dilated bc lack of parasymp
Always looks towards lesion w/ that eye
Turn his head so always looking in direction of lesion to avoid diplopia

16

Sign of IV Lesion

Head tilted opposite direction of lesion to compensate

17

Parkinson's

DA Loss in substantia nigra

18

Weber's Syndrome

Caused by stroke in branch of posterior cerebral or basilar a.
Ipsilateral loss of III and contralateral loss of motor control of skeletal muscles