CRANIAL NERVES OF SCOLIODON (SHARK)
SHARK FISH (SCOLIODON) CRANIAL NERVES ORIGIN AND PHYSIOLOGICAL FUNCTION
Ten pairs of cranial nerves arise from the brain at different locations to supply the anterior region of the body. In addition to them a pair of terminal or pre olfactory nerves (zero nerves) arises from the ventral surface of the cerebrum.
The ten pairs of cranial nerves are furnished below for detail study.
| 1. BRANCHIALIS X |
| 3. LATERALIS X |
| 4. BUCCALIS VII |
| 5. CEREBELLUM |
| 6. OPTIC III |
| 7. OPHTHALMICUS SUPERFICIALIS V& VII |
| 8.OLFACTORY LOBE |
| 9.BUCCALIS VII |
| 10. PALATINUS VII |
| 11.MAXILLARIS INFERIOR V |
| 12.MANDIBULARS V |
| 13. MANDIBULARS EXTERNUS VIII |
| 14. HYOMANDIBULARIS VII |
| 15. PHARYNGEAL |
| 16. OPHTHALMICUS PROFUNDUS V |
| 17. POST TREMATIC PRETREMATIC IX IX |
| 18. MANDIBULARS INTERNUS VII |
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Name of the nerve |
Origin |
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Branches |
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Distribution |
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Physiological Nature |
| I. OLFACTORY | Olfactory lobe. | Olfactory epithelium of the nasal cavity. | Sensory | ||||
| 2. OPTIC | Optic lobe. | Retina of eye. | Sensory | ||||
| 3. OCULOMOTOR | Ventrolateral side ofthe midbrain. | Anterior rectus, superior rectus, inferior rectus and inferior oblique muscles of the eye. Superior oblique muscle of the eye | Motor Motor | ||||
| 4 TROCHLEAR | Dorsolateral aspect of the midbrain between the optic lobes and cerebrum. | Olfactory capsule and dorsal | Mixed | ||||
| 5 TRIGEMINAL | Dorsally from the side of medulla oblongata below the corpora restiformes. | (i) Opthalmic profundus (ii) Ophthalmicus superfi-cialis V (iii) Maxillaris V (a) Superior (b) Inferior (iv) Mandibularis | skin of the snout. Skin of the snout. Skin of upper jaw Posterior part of upper lip. Muscles of the lower jaw. | Mixed Motor Mixed | |||
| 6. ABDUCENS | Midventrally from the floor of medulla oblongata | Posterior rectus muscle of the eye. | Mixed | ||||
| 7. FACIAL | From the side of medulla below the corpora restiformes in the form of a bundle. | (i) Opthalmicus super-ficialisVII (ii) Ramus buccalis (iii) Flyomandibularis (a) Mandibularis exte-rnus (b) Mandibularis inter-nus (c) Hyoidean (iv) Ramus palatinus | Sense organs; the lateral line system of snout. Infra-orbital lateral line canal and associated ampullae. Mandibular canal of lateral-line system. Mucous membrane of the floor of buccal cavity. Muscles of the roof of buccal cavity and pharynx. Roof of the pharyngeal and buccal cavity. | Mixed Mixed Mixed Mixed Mixed Sensory | |||
| 8. AUDITORY | From the side of medulla close to the V and Vll cranial nerves. | (i) Vestibular (ii) Saccular | Membranous labyrinth of the internal ear | Sensory | |||
| 9. GLOSSOPHARYN GEAL | From the ventro-lateral side of medulla. . | (i) Pre-trematic (ii) Post-trematic | Mucous membrane of the first gill-cleft and the pharynx. The muscles of the pharynx Gills. | Sensory Mixed Mixed | |||
| 10. VAGUS | Side of Medulla. | (a) Branchialis (b) Visceralis (c) Lateralis | Viscera. Lateral-line system of the trunk. | Mixed Mixed Mixed |