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41 Cards in this Set
- Front
- Back
Major subdivisions of brainstem |
Mesencephalon Pons Medulla |
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Mesencephalon structures |
Cerebral aqueduct - connects third and fourth ventricle. Tectum - Ceiling of cerebral aqueduct, composed of superior and inferior colliculi Tegmentum - Floor of cerebral aqueduct |
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Medulla |
Open portion which borders fourth ventricle Closed portion unconnected to ventricles |
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Cerebellum |
Connected to mesencephalon by superior cerebellar peduncle Connected to pons by middle and inferior cerebellar peduncles |
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Structures of brainstem |
Midline groove On either side is sulcus limitans Rhomboid shaped fourth ventricle, bottom is called obex. Middle cerebellar peduncle connecting cerebellum to pons |
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Sulcus limitans importance |
Sulcus limitans separates motor nuclei from autonomic and sensory nuclei. |
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Pyramids Base of pons with basilar artery Pyramidal decussation Abducens nerve |
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Cranial nerves on medial and lateral side of olive |
Medial side of olive (medial periolivary groove) - XII Lateral side of olive (lateral periolivary groove) - IX, X, XI |
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Inferior olive |
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Difference between organization of brain stem and spinal cord |
Dorsal horn (somatic and visceral sensory) of spinal cord moves to be lateral Ventral horn (somatic and visceral motor) of spinal cord moves to be medial |
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Precursor of sensory and motor nuclei |
Alar plate gives rise to sensory nuclei Basal plate gives rise to motor nuclei Alar and motor plate are separated by sulcus limitans |
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Order of brainstem nuclei |
Medial (purely motor) - III, IV, VI, XII Lateral but medial to sulcus limitans - V, VII, nucleus ambiguus (IX, X, XI) Lateral - autonomic centers i.e.salivatory nuclei Lateral-most - sensory nuclei - mesencephalic nucleus of trigeminal, principal nucleus of trigeminal, spinal trigeminal nucleus (sensory nerves for V, VII, IX, X, XI) |
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Sensory information in cranial nerves |
General sensory: touch, temperature, pain, spindles Visceral sensory: stretch, visceral pain Special sensory: vision, hearing, smell, taste |
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Motor information in cranial nerves |
Somatic motor from somite or branchial arches derived muscles Visceral motor - parasympathetic (craniosacral) |
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First order sensory neurons |
Pseudounipolar cells Ganglion is outside brain typically. Except mesencephalic sensory neurons, where ganglion is in brainstem |
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Sensory nuclei |
Dorsal and ventral cochlear nuclei (VIII) - hearing Medial, lateral, superior,inferior vestibular nuclei (IX) - balance Mesencephalic nucleus of trigeminal nerve (V) - proprioceptive reflex Principal sensory nucleus of trigeminal nerve (V) - somatosensory Spinal nucleus of trigeminal nerve (V, VII, IX, X) - somatosensory Nucleus of solitary tract - (IX, X) - special sensory |
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Spinal trigeminal nucleus |
Sensory nerves for V, VII, IX, X, XI Continuation of dorsal horn's substantia gelatinosa |
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Motor nuclei |
Oculomotor (III) Trochlea (IV) Trigeminal (V) Abducens (VI) Facial (VII) Nucleus ambiguus (IX, X, XI) Accessory nucleus (XI) Hypoglossal nucles (XII) |
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Edinger-Westphal nucleus |
Autonomic but located medial to motor nucleus of oculomotor Joins oculomotor nerve, Innervates ciliary ganglion which sends fibers to muscle of eye to regulate pupil size. |
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Parasympathetic functions |
Pseudomotor - regulate secretion Vasomotor - regulate smooth muscle |
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Parasympathetic motor nuclei |
Edinger-Westphal nucleus (leave through III) Superior salivatory nucleus (leave through VII) - to pterygopalatine, submandibular, and sublingual Inferior salivatory nucleus (leave through IX) - to otic ganglion, innervate parotid Dorsal motor nucleus of vagus |
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Trigeminal autonomics |
Trigeminal system has no autonomics but other cranial nerves travel along trigeminal to reach target e.g. auriculotemporal n. to parotid |
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Colliculus facialis |
Protrusion on floor of fourth ventricle Formed by fibers leaving facial nucleus looping around abducens nuclei. Medial protrusions are motor, lateral are sensory, and in between but lateral to sulcus limitans is autonomic. |
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Oculomotor nerve |
Motor nucleus just below Edinger-Westphal |
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Mesencephalic spinal trigeminal nucleus |
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Trochlear nucleus |
Supplies superior oblique |
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Trigeminal nerve system |
Has somatosensory and somatomotor nucleus in pons Tract comes up from spinal cord as substantia gelatinosum and continues up to mesencephalon at level of oculomotor nerve. |
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In pons, motor nucleus of trigeminal nerve is medial to principal nucleus of trigeminal nerve |
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Tract of spinal trigeminal nucleus is lateral to nucleus |
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Abducens n. |
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Facial nerve |
Motor Autonomic efferent - superior salivatory Visceral sensory - nucleus of solitary tract General sensory - spinal trigeminal nucleus |
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Vestibulocochlear nerve |
Cochlear nuclei and vestibular nucleus |
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Glossopharyngeal nerve |
General sensory from tongue, ear - Spinal trigeminal Autonomic - inferior salivatory (otic) Special sensory from carotid body, tastef - solitary tract Motor to stylopharyngeus - nucleus ambiguus |
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Vagus nerve |
Nucleus ambiguus - striated to pharynx, tongue, larynx Dorsal nucleus of vagus - parasympathetic Solitary tract - special sensory i.e. taste from epiglottis Spinal trigeminal - general sensory |
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Structures around middle cerebellar peduncle |
Connects cerebellum to pons In front - trigeminal Behind - facial and vestibulocochlear |
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Find abducens |
Between pons and medulla close to midline |
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Identifying oculomotor nerve |
In front of pons behind medullary body between posterior cerebellar and posterior cerebral artery. |