Midbrain-general Flashcards
The area that makes up the roof of the midbrain
Tectum
The tectum is (blank) to the cerebral aqueduct
posterior
how many collicular bodies are present in the tectum?
four: two superior and two inferior
What is the main function of the superior collicular bodies
mostly visual function
The main function of the inferior collicular bodies
mostly auditory function
The function of the cerebral aqueduct
transport CSF between 3rd and 4th ventricles
The area immediately surrounding the cerebral queduct
periaqueductal gray substance or central gray
What two cranial nerves have their nuclei and apparent origins within the midbrain
CN III (oculomotor) and IV (trochlear)
Which of the extraocular eye muscles are innervated by the trochlear nerve?
Superior Rectus
The trochlear nerve has its apparent origin on what part of the midbrain?
Mid-dorsal aspect just inferior to the inferior colliculus
The four unique characteristics of C.N. IV
1) Smallest of the cranial nerves
2) only C.N. w/ apparent origin on the posterior aspect of the brain stem
3) fiber will cross as they exit the CNS
4) travels farther within the cranial vault than any other C.N.
Where is the apparent origin of C.N. III?
Ventral from the interpeducular fossa
Where are the six nuclei of origin for this cranial nerve located?
within the periaqueductal gray substance area
What is the major function of the oculomotor nerve?
Innervate four of the six extraocular eye muscles (superior rectus, inferior rectus, medial rectus, inferior oblique) Also the levator palpebrae superioris
What are some other functions of C.N. III?
-carries preganglionic parasympathetic axons to the accessory oculomotor nucleus to the ciliaris and the sphincter pupille of the eye
