Transcript Document
CRANIAL NERVES - LECTURE A NBIO 401 – Wednesday, October 6, 2010 Objective for the first two cranial nerve lectures, those about cranial nerve nuclei: -Be able to summarize the function and location of each cranial nerve nucleus. I Optic Nerve II III V VI VII VIII IX X XII I ONLY III - XII Optic Nerve II III V VI VII VIII IX X XII I CRANIAL NERVE NUCLEI A = III - V Optic Nerve II III V VI VII VIII IX X XII I Optic Nerve II III CRANIAL NERVE NUCLEI B = VI - XII V VI VII VIII IX X XII Sensory GSA and SSA Mesencephalic Trigeminal V (jaw muscle spindles) Main Sensory Trigeminal V (face touch & proprioception) Vestibular/ Cochlear VIII (vestibular & auditory signals from the inner ear) GENERAL SOMATIC CRANIAL NERVE NUCLEI Motor GSE Oculomotor III (eye muscles) Trochlear IV (eye muscles) Abducens VI (eye muscles) Spinal Trigeminal V (face pain) Hypoglossal XII (tongue muscles) Sensory GVA GENERAL VISCERAL CRANIAL NERVE NUCLEI Motor GVE Edinger-Westphal III (constricts pupil parasympathetic) Superior salivatory VII (drives salivary glands parasympathetic) Inferior salivatory IX (drives salivary glands parasympathetic) Solitarius (caudal half) VII, IX, X (sensory information for autonomic control) Dorsal motor n. of X (parasympathetic drive to smooth muscles & organs in chest and abdomen) Sensory SVA Special Visceral CRANIAL NERVE NUCLEI Motor SVE Motor Trigeminal V (chewing muscles) Solitarius (rostral half) VII, IX, X (taste) Facial VII (muscles of facial expression) n. Ambiguus IX, X (muscles of the pharynx & larynx) Motor nuclei locations General Somatic Efferents lie close to the midline General Visceral Efferents lay laterally to the General Somatic Efferents Cranial Nerves III - V Edinger Westphal nucleus (constricts the pupil) Oculomotor nucleus (motoneurons for eye muscles) Oculomotor nerve (to eye muscles & pupil muscles) QuickTime™ and a GIF decompressor are needed to see this picture. Trochlear nerve (to eye muscles) Trochlear nucleus (motoneurons for eye muscles) Special Visceral (Branchial) Efferents lie most lateral of the motor nuclei. To Thalamus Mesencephalic trigeminal nucleus (1° sensory neurons for muscle spindles & joint receptors in head) Mesencephalic trigeminal tract (axons bringing unconscious signals from muscle spindles & joints in head) Sensory Axons of 1° sensory neuron for unconscious muscle spindle & joint receptors (cell body in mesencephalic trigeminal nucleus - the only 1° sensory cell body inside CNS) Sensory Axons signals for conscious touch & muscle spindle/joint receptors (cell body in ganglion outside CNS) Trigeminal nerve (sensory & motor axons of 4 types listed to the right) Motor Axons carrying motor signals to jaw muscles (cell body motor trigeminal nucleus) Sensory Axons signals for pain & temperature (cell body in ganglion outside CNS) Motor trigeminal nucleus Motor trigeminal nucleus (motoneurons for jaw muscles) Trigeminal nerve Main sensory trigeminal nucleus (afferent: touch, muscle spindle/joint, (touch, conscious pain & temperature from head spindle & joint from head) efferent: chewing muscles) Main sensory trigeminal nucleus Trigeminal nerve Spinal trigeminal nucleus Spinal trigeminal nucleus (pain & temperature from head) Mesencephalic trigeminal tract Motor Mesencephalic Trigeminal trigeminal nucleus nucleus Trigeminal Main sensory nerve trigeminal nucleus Spinal trigeminal nerve (1° axons on way to terminate in spinal trigeminal nucleus) Main sensory trigeminal nucleus Trigeminal nerve Spinal Trigeminal nucleus Spinal trigeminal nucleus Superior cerebellar peduncle (fibers coming out of cerebellum) Middle Cerebellar peduncle MLF Main sensory trigeminal Nucleus (face touch) Spinal trigeminal tract & nucleus Motor nucleus of trigeminal (chewing muscle motoneurons) Pyramidal Tract Spinothalamic tract Pontine Gray matter Medial lemniscus Superior cerebellar peduncle Mesencephalic trigeminal tract & nucleus (muscle spindles from chewing muscles & jaw joint receptors) Motor trigeminal nucleus Middle Cerebellar peduncle MLF Trigeminal nerve ( sensory & motor for the head) Spinothalamic tract Pyramidal Tract Pontine Gray matter Medial lemniscus Medial Longitudinal Fasciculus Mesencephalic trigeminal tract & nucleus Superior Cerebellar peduncle Spinothalamic tract Pyramidal Tract Pontine Gray matter Medial lemniscus Facial nerve fibers (looping around abducens nucleus) Abducens Nucleus (eye muscle motoneurons) Vestibular nuclei Spinal trigeminal nucleus & tract MLF Inferior cerebellar peduncle Facial motor nucleus Spinothalamic Tract Middle Cerebellar peduncle Pyramidal Tract Medial lemniscus Pontine Gray matter Central canal Gracile Nucleus (touch-leg) Gracile Fasciculus (touch-leg) Cuneate Nucleus (touch-arm) Spinal trigeminal nucleus & tract (head pain & temp) Spinal Accessory Nucleus (motoneurons for trapezius & sternocleidomastoid muscles) Medial Longitudinal Fasciculus (MLF) (vestibular & oculomotor information) Pyramidal Decussation (corticospinal fibers crossing midline) Cuneate Fasciculus (touch-arm) Spinothalamic Tract Pyramids (body pain) (corticospinal fibers) Spinocerebellar Tract (sensory fibers - Muscle spindle & joint information to cerebellum - leg)