1 Cranial Nerves Originates from brain (mainly brain stem) and passes through foramina of skull There are 12 pairs of cranial nerves They have both name and number

2 There are mixed cranial nerves, sensory cranial nerves and motor cranial nerves All motor cranial nerves contain a small number of sensory fibers that is proprioceptive

3 Olfactory nerve I The axons that makes the olfactory nerve starts from nasal mucosa. They make 20 small bundles of fibers that pierce the cribriform plate Olfactory nerve carry the sense of smell

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5 Optic nerve II Axons start in retina They carry visual information to brain. Most of the optic tract fibers terminate in thalamus.(lateral geniculate nucleus)

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7 Occulomotor nerve III Starts from occulomotor nucleus in the ventral part of the midbrain. Extends to various external eye muscles

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9 Trochlear nerve IV Originates from the midbrain They go to the superior oblique muscle of the eye

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12 Trigeminal nerve V It splits into three large branches It makes ophtalmic nerve, maxillary nerve, mandibular nerve Carry sensory information from face and teeth Its motor nerve controls mastication

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14 Abducence nerve VI Its fibers originate from pons and extends to the lateral rectus muscle of the eye. This muscle abducts the eye.

15 CN VI

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17 Facial nerve VII Arise from the lower part of the pons. Innervates superficial muscles of face and skull. Its autonomic fibers innervate the submaxillary and sublingual salivary glands and lacrimal glands.

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20 Vestibulocochlear nerve Has two distinct divisions: Vestibular and cochlear

21 Vestibular branch Arise from semicircular canals in internal ear and terminates in pons medulla and cerebellum. Its function is to maintain equilibrium.

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24 Cochlear branch Starts from the organ of corti and terminate between medulla and pons. Conduct the sense of hearing. Its some times called auditory or acoustic nerve.

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26 Glossopharyngeal nerve Glossopharyngeal nerve IX It is a mixed nerve. Supplies the tongue and pharynx It also supplies the carotid sinus Its fibers extend to medulla.

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28 Vagus nerve X Contains sensory and motor fibers It has many widely distributed branches pharynx, larynx, trachea, heart, carotid body, lungs, bronchi, esophagus, stomach, small intestine and gall bladder Sensory fibers supply, pharynx, larynx, trachea, heart, carotid body, lungs, bronchi, esophagus, stomach, small intestine and gall bladder

29 motor fibers of vagus nereve Are mainly autonomic. They controls muscles for swallowing Most of them are parasympathetic. They also go to pharynx, larynx, thoracic organs and abdominal organs.

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32 Accessory nerve XI Is a motor nerve Is considered an accessory nerve to vagus. It was formerly called the spinal accessory nerve

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35 Hypoglossal nerve XII The motor fibers supplies the muscles of the tongue It also have sensory (proprioceptive) nerves.

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37 Divisions of peripheral nervous system Sensory division Sensory division Motor division Motor division

38 Somatic motor nervous system Includes all the voluntary movements outside the CNS acetylcholine The end motor neuron stimulates the effector muscle by means of acetylcholine

39 Somatic reflexes A reflex is a predictable response to an stimulus Based on the center of a reflex we have cranial and spinal reflexes. We also have somatic reflexes and autonomic reflexes

40 Autonomic reflexes Is either muscle contraction or glandular secretion Cause Smooth or cardiac muscle contraction or secretion of a gland

41 Important somatic reflexes Knee jerk reflex Ankle jerk reflex Babinski reflex Corneal reflex Abdominal reflex

42 Knee jerk reflex Is extension of lower leg in response to tapping patellar tendon spinal cord reflex, segmental reflex, stretch reflex, extensor reflex and deep tendon reflex. It is also a spinal cord reflex, segmental reflex, stretch reflex, extensor reflex and deep tendon reflex.

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44 Ankle jerk reflex It is called achilles reflex Cause plantar flexion Its center is in the first and second segment of the cord

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46 Babinski reflex Is extension of great toe Infants show this reflex up to 1 ½ yrs After that it is considered abnormal

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48 Corneal reflex Is blinking in response to touching the cornea It is mediated by the ophtalmic branch of fifth cranial nerve Centers in the pons and motors in seventh cranial nerve

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50 Abdominal reflex Is drawing in of the abdominal wall in response to stroking the side of the abdomen Its center is in 9 th to 12 th spinal nerves In pregnancy it is abscent.

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