Cranial Nerve I and Olfactory pathways.pptx

Students should have a thorough knowledge about the various functional components of cranial nerve(s) nuclei.

Students should be able to identify the exact locations of the cranial nerve nuclei and the origin and exits of cranial nerves .

Students should be able to explain the Course, Branches and functions of all cranial nerves.

Students should be Describe the dysfunctions associated with lesions of each cranial nerve.
Sensory cranial nerves: contain only afferent (sensory) fibers
Ⅰ Olfactory nerve
Ⅱ Optic nerve
Ⅷ Vestibulocochlear nerve
Motor cranial nerves: contain only efferent (motor) fibers
Ⅲ Oculomotor nerve
Ⅳ Trochlear nerve
Ⅵ Abducent nerve
Ⅺ Spinal Accessory nerve
Ⅻ Hypoglossal nerve
Mixed nerves: contain both sensory and motor fibers
Ⅴ Trigeminal nerve,
Ⅶ Facial nerve,
Ⅸ Glossopharyngeal nerve
Ⅹ Vagus nerve

1. CRANIAL NERVES Students should have a thorough knowledge about the various functional components of cranial nerve(s) nuclei. Students should be able to identify the exact locations of the cranial nerve nuclei and the origin and exits of cranial nerves . Students should be able to explain the Course, Branches and functions of all cranial nerves. Students should be Describe the dysfunctions associated with lesions of each cranial nerve . LEARNING OBJECTIVES:

2. 12 PAIRS OF CRANIAL NERVES Ⅰ Olfactory nerve Ⅱ Optic nerve Ⅲ Oculomotor nerve Ⅳ Trochlear nerve Ⅴ Trigeminal nerve Ⅵ Abducent nerve Ⅶ Facial nerve Ⅷ Vestibulocochlear nerve Ⅸ Glossopharyngeal nerve Ⅹ Vagus nerve Ⅺ Accessory nerve Ⅻ Hypoglossal nerve

3. CLASSIFICATION Sensory cranial nerves : contain only afferent (sensory) fibers Ⅰ Olfactory nerve Ⅱ Optic nerve Ⅷ Vestibulocochlear nerve Motor cranial nerves : contain only efferent (motor) fibers Ⅲ Oculomotor nerve Ⅳ Trochlear nerve Ⅵ Abducent nerve Ⅺ Spinal Accessory nerve Ⅻ Hypoglossal nerve Mixed nerves : contain both sensory and motor fibers Ⅴ Trigeminal nerve, Ⅶ Facial nerve, Ⅸ Glossopharyngeal nerve Ⅹ Vagus nerve

4. SUBDIVISIONS OF VERTICAL COLUMNS Motor nuclei Somatic motor closest to midline eyes, tongue CN III, IV, VI, XII Branchial motor Lateral position Branchial arches: chewing, expression, middle ear, pharynx, larynx, sternomastoic, trapezius CN V, VII, XI N. ambiguus (IX, X) Visceral motor ventral / ventrolateral Parasympathetic: glands, smooth muscle, heart, lungs, GI above splenic flexure Edinger-Westfall (III) Sup. & Inf. salivatory (VII) Dorsal motor nucleus of X Sensory nuclei General (Somato) sensory lateral to branchial motor Face, sinuses, meninges All modalities CN V mainly Also CN VII, IX, X Visceral sensory (General and Special) lateral to visceral motor Taste; cardiorespiratory, GI info N. of the solitary tract (CN VII, IX, X) Special sensory furthest lateral Balance; hearing CN VIII (vestibular) CN VIII (cochlear)

5. BRAINSTEM / FUNCTIONAL COMPONENTS GSE SVE GVE GVA SVA GSA SSA MIDBRAIN III CN (Motor Nucleus) III CN ( Edinger Westphal Nucleus) IV CN (Motor Nucleus) PONS VI CN (Motor Nucleus) V CN (Motor Nucleus) VII CN (Superior SalivatoryNucleus) VII CN (Motor Nucleus) MEDULLA OBLONGATA XII CN (Hypoglossal Nucleus) IX, X & XI CN (Nucleus Ambiguus) IX CN (Inferior Salivatory Nucleus) X CN (Dorsal Motor Nucleus) VII CN IX CN X CN IX CN X CN V CN V CN V CN IX CN X CN VIII CN VII CN VII CN Nucleus Tractus Solitarius

6. FUNCTIONAL COMPONENTS General somatic afferent fibers (GSA): exteroceptive and proprioceptive impulses from head and face to somatic sensory nuclei Special somatic afferent fibers (SSA): sensory impulses from special sense organs of vision, equilibrium and hearing to the brain General visceral afferent fibers (GVA): interoceptive impulses from the viscera to the visceral sensory nuclei Special visceral afferent fibers (SVA): sensory impulses from special sense organs of smell and taste.

7. General somatic efferent fibers (GSE): innervate skeletal muscles of eye and tongue Special visceral efferent fibers (SVE): transmit motor impulses from the brain to skeletal muscles derived from branchial arches (muscles of mastication, facial expression and swallowing) General visceral efferent fibers (GVE): transmit motor impulses from the general visceral motor nuclei and relayed in parasympathetic ganglions (cardiac muscles ， smooth muscles and glands) FUNCTIONAL COMPONENTS

8. CRANIAL NERVE - I

9. CRIBIFORM PLATE SENSORY = Name: Olfactory nerve Foramen: Cribiform plate Fiber Type: Special sensory Function: Olfactory bulbs, Smell Branches: Olfactory filaments Embryo: CNS (ectoderm) OLFACTORY NERVE

10. Function : Special sensory (special visceral afferent) The cell bodies of olfactory receptor neurons are located in the olfactory organ (the olfactory part of the nasal mucosa or olfactory area), which is located in the roof of the nasal cavity and along the nasal septum and medial wall of the superior nasal concha. The apical surfaces of the neurons possess fine olfactory cilia, bathed by a film of watery mucus secreted by the olfactory glands of the epithelium. The cilia are stimulated by molecules of an odiferous gas dissolved in the fluid. OLFACTORY NERVE

11. Olfactory bulb Olfactory tract Anterior perforated substance Uncus Bypass thalamus and goes directly into the taste area Nerve filaments Cribriform plate of ethmoid bone OLFACTORY NERVE

12. Receptors and the first neurons

13. Olfactory Pathways

14. Olfactory Bulb

15. Fourth neurons

16. Olfactory Pathways

17. Purpose of Test

18. The End Thank you