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cranial nerves
theories
| Question | Answer |
|---|---|
| Function of the nerves; sensory or motor is to sense or supply muscles | Vagus is the longest; serves upper body and abdominal area. |
| The nucleus of the nerves cross over at the optic chiasm. most of the nerves are in the area of the brain-stem | Olfactory nerves pass through holes in the cribriform plate and then to the olfactory bulb. |
| The olfactory tracts lead from these bulbs back to the thalamus and then to the frontal lobe for smell perception | Special Visceral Afferents;;Chemical senses taste and smell if no taste then no smell |
| pathway of the optic nerve...optic tract--thalamus--visual cortex. Medial fibers cross, lateral fibers remain on same side (lateral same eye | Special senses only found in the head=Vision II, Hearing and Ballance VII |
| Oculomoter parasympathetic fibers control muscles of iris for constricting pup. Controls extrinsic eye muscles Superior & Inferior rectus and Inferior oblique muscles. bilateral 6 total | Trochlear contsol the superior oblique muscle of the eye. Stabilizes eye. Pulley shaped. Between pons and the midbrain |
| Trigeminal- Great sensory nerve of the head. largest nerve in the body. | Trigeminal-Three divisions: opthalmic, maillary and mandibular |
| Abducens abducts the eye controls lateral rectus muscle | Extraocular muscles-adduct..move medially; abduct...move laterally; elevate depress. rotate, intorsion and extorsion 6 directions |
| lateral rectus CN VI; Superior Oblique CN IV All else CN III | Subarachnoid space extends to back of eye |
| Ciliary Ganglion: parasympathetic. 1)ciliary muscles 2) sphincter. innervated by CN III | Abducens nerve damage lateral stylabismus (cross-eyed) dut to damage to lateral erectus |
| with Trochear damage--inability to turn eye down and out..superior oblique | Lateral strabismus oculomotor damage to medial rectus |
| LR lateral VI/SO down and lateral IV/ MR medial III, SR up and medial III, IR down and medially III, IO up and laterally III, SO down and laterally III. | VII-Facial; Motor to muscles of facial expression; control of lacrimal and salivary glands. sensory taste anterior 2/3 otor to facial expression |
| VII Facial leaves posterior cranial fossa via Internal Auditory Meatus---enters facial canal | Greater Petrosal N (Facial VII) forms Nerve of Pterygoid Canal |
| Muscles of facial expression--1. Temporal - auricular 2. Zygomatic - muscles of the zygomatic arch . 3. Buccal - muscles in the cheek and above the mouth. 4. Mandibular - muscles in the region of the mandible. 5. Cervical - the platysma muscle | Pathway to lacrimal gland: Greater Petrosal N. to Pterygopalatine Ganglion to Lacrimal |
| Lacrimal Gland-Post-ganglionic Parasymp. join Zygomatic to V1 Lacrimal | Pathway to mucus gland of nose, palate: Greater Petrosal N. to Pterygopalatine Ganglion to Musus Glands Nose , Palate via greater and lesser palatine N. |
| Pathway to submandibular, sublingual , salviary glands, taste fibers to ant 2/3 tongue. Chorda typani around lingual nerve submandibular ganglion to tongue and glands | Greater Petrosal-mucus glands of nose and plalate form N. of Pterygoid Canal, synapse in Pterygoid Palatine Ganglion |
| Chorda Tympani-Submandibular and sublingual glands, tast fibers to ant 2.3 of tongue | Vestibulocochlear VIII-Just above spinal cord at the pons. ends in Cochlea and semicircular Canals |
| Int. aud. meatus | Glossophryngeal after ear nuclei at level of medulla and parotid gland. |