Midbrain (dave's notes) Flashcards
Where does most of the midbrain lie?
Most lies in the posterior cranial fossa, with the upper part passing through the tenurial notch
What does the midbrain consist of?
Right and left halves (peduncles), each with ventral and dorsal parts
What is the appearance of the ventral and dorsal midbrain?
Ventrally the peduncles lie in a v-shaped manner
Dorsally the midbrain is roughly cylindrical with superior and inferior coliculi
What nerves does the midbrain give rise to? From what surfaces do they arise?
The oculomotor (leaves medial surface) and trochlear nerves (leaves dorsal surface)
How does the optic tract lie?
Curling around the peduncle
What vein passes ventrally to the optic tract?
The basal vein on its way from the anterior perforated substance to the great cerebral vein
What artery passes ventrally to the optic tract?
The posterior communicating artery joins the posterior cerebral and internal carotid arteries
Internal structure: How are sections recognised within the midbrain?
By their colliculi on the dorsal surface.
What cells are responsible for general light reflexes?
Cells of the superior colliculus
What cells are responsible for sound reflexes?
Cells of the inferior colliculus
Where is the substantial nigra found? What does it belong to? What may it contain?
In the upper part of the midbrain. Officially belongs to the basal nuclei. Many contain melatonin?? metatonin?
Where is the oculomotor nuclei found? What is found in the midline of the cranial part?
Close against the midline surface.
The Edinger-westphal or accessory occulomotor nucleus
What is the significance of the red nucleus?
Seem to be of little functional significance in man, not associated with any known disease. Has associated tracts
What is found lateral to the cerebral aqueduct?
The mesencephalic nucleus (CrN V). This receives proprioceptive fibres
What is the blood supply to the midbrain?
By the posterior cerebellar artery and superior cerebellar arteries
