Neuroanatomy

Description:	12 Cranial Nerve
Category:	Anatomy
Created by:	adhass on 2008-09-26

Auditory and vestibular systems - external ear- collects and focuses sound waves to the tympanic membrane - middle ear- transmits vibrations across the chain of occicles through transduction. - Inner ear- sound waves are converted to action potentials for processing o Fluid filled chamber - Perilymph is between the bone and membrane o It is similar to CSF and is continuous with the subarachnoid space of the cranial cavity - the membranous labyrinth in the cochlea contains a primary sensory transducer for sound, the organ of corti - high frequency sounds activate hair cells near the base of the cochlea, while low frequency activate hair cells near apex. - Cranial nerves 5 (tensor tympani) & 7 (stapedius muscle) protect the ear by dampening loud sounds - Labyrinths (bony & membranous) consist of o Semicircular canals o Vestibule o Cochlea - central pathways of cochlearnerve: o cochlear nerve -> brainstem -> cochlear nuclei -> inferior colliculus -> thalamus (medial geniculate nucleus) -> auditory cortex of temporal lobe (heschels gyri) - Divisions of the vestibular system o Vestibular apparatus  2 portions • Vestibule (contains saccule and utricle) • Semicircular canals - The static sensory detectors are located in the saccule and utricle of the vestibule - The kinetic receptors are in the semicircular canals - The hair cell of the static and kinetic labyrinths are innervated by vestibular ganglion - Lateral vestibulospinal tract is extensor based and helps control balance - Medial vestibulospinal tract primarily controls posture of the head and neck - The basic anatomy of the vestibule-ocular network involves connections of the vestibular nuclei with the oculomotor nuclei of cranial nerves 3, 4, and 6 through the medial longitudinal fasciculus - Static labyrinth- otolith organs- detect position of the static position head relative to gravity, also linear acceleration - Kinetic labyrinth- cristae ampullaris- dynamic movement particularly rotational; also some speed of movement - The vestibule-thalamocortica (network is responsible for conscious perception of orientation

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Cardio Block2anatomy

Question	Answer
CN I	Olfactory, Sensory,
CN II	Optic, Sensory, Uncus of Temporal Lobe
CN III	Oculomotor, Motor, Midbrain
CN IV	Trochlear, Motor, Midbran
CN V	Trigeminal, Mixed, Pons
CN VI	Abducens, Motor, Junction of Pons and Medulla
CN VII	Facial, Mixed, Junction of Pons and Medulla
CN VIII	Vesibulocochlear, Sensory Junction of Pons and Medulla
CN IX	Glossopharyngeal, Mixed, Medulla
CN X	Vagus, Mixed, Medulla
CN XI	Spinal Accessory, Motor
CN XII	Hypoglossal, Motor, Medulla

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Neuroanatomy