Cranial Nerves Flashcards
What are the purely sensory cranial nerves?
CN I (olfactory) CN II (vision) CN VIII (balance, hearing) (vestibulocochlear nerve)
What are the purely motor cranial nerves?
CN III (occulomotor) CN IV (Trochlear)) CN VI (Abducens) CN XI ((spinal accessory nerve) CN XII (hypoglossal)
Of the five purely motor cranial nerves, how many are involved in movements of the eyes?
Three. The oculomotor nerve (CN III), the trochlear nerve (CN IV), and the abducens nerve (CN VI). “III IV VI make the eyes do tricks”
What are the mixed cranial nerves?
CN V (trigeminal) CN VII (facial) CN IX (glossopharyngeal) CN X (vagus) (notice how all are involved in pharyngeal arch development)
What kind of special senses do SSA fibers transmit?
Vision, hearing, and balance. In other words senses that don’t involve chemical reactions.
What kind of special senses do SVA fibers transmit?
Taste and olfaction (senses that involve chemical reactions).
Why are there no SSE fibers?
Because by definition somatic efferent fibers can be carried by both cranial and spinal nerves. So there are only GSE fibers.
Is it possible for cranial nerve nuclei in the brainstem to be mixed?
No. This is why mixed cranial nerves (CN V, CN VII, CN IX, CN X) involve multiple nuclei.
What is special about the trochlear nerve (CN IV)?
It emerges from the brainstem posteriorly and then wraps around anteriorly.
What are the three portions of the brainstem?
The mesencephalon (midbrain), the pons, and the midbrain.
What cranial nerves exit at the junction of the midbrain and the pons?
CN III and IV.
What cranial nerve exits from the body of the pons?
CN V.
What cranial nerves exit at the junction of the pons and the medulla oblongata?
CN VI, VII, VIII, and IX.
What cranial nerves exit off of the medulla oblongata?
CN X, XI, and XII.
