Flashcards in Midbrain Deck (18)
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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
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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
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Sign of IV Lesion
Head tilted opposite direction of lesion to compensate
17
Parkinson's
DA Loss in substantia nigra
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