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Peripheral Nervous System

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Presentation on theme: "Peripheral Nervous System"— Presentation transcript:

1 Peripheral Nervous System

2 Peripheral Nervous System (PNS)
Nerves and ganglia outside the central nervous system Nerve = bundle of neuron fibers Neuron fibers are bundled by connective tissue

3 PNS: Structure of a Nerve
Endoneurium surrounds each fiber/axon Groups of fibers are bound into fascicles by perineurium Fascicles are bound together by epineurium

4 PNS: Classification of Nerves
Mixed nerves Both sensory and motor fibers Sensory (afferent) nerves Carry impulses toward the CNS Motor (efferent) nerves Carry impulses away from the CNS

5 Cranial Nerves 12 pairs of cranial nerves
Control head, neck, part of trunk, and upper limbs Numbered in order and name tells about its function

6 Cranial Nerves I. Olfactory– sensory, carries impulses for sense of smell II. Optic—sensory, carries impulses for vision III. Oculomotor—motor, controls 4 of 6 eye movement muscles, eyelid, lens shape, and pupil size IV. Trochlear—motor, controls external eye muscles V. Trigeminal—sensory: conducts impulses from skin of face and mucosa of nose and mouth. Motor: fibers that activate chewing muscles VI. Abducens—motor, controls muscles that roll the eye laterally

7 Cranial Nerves VII. Facial—activates muscles of facial expression, lacrimal and salivary glands. Also carries sensory info from the taste buds of anterior tongue. VIII. Vestibulocochlear—sensory, vestibular branch transmits info for sense of balance, cochlear branch transmits info for sense of hearing IX. Glossopharyngeal—motor: supplies fibers to the throat that promote swallowing and saliva production. Sensory: transmits info from taste buds of posterior tongue and pressure receptors of the carotid artery X. Vagus—carries sensory and motor info to the throat, voicebox and abdominal/thoracic viscera

8 Cranial Nerves XI. Accessory—motor, fibers activate trapezius and sternocleidomastoid muscles XII. Hypoglossal—motor, control of tongue movements. Sensory—carry impulses from the tongue Mnemonic Device: On, On, On, They Traveled And Found Voldemort Guarding Very Ancient Horcruxes

9 PNS: Spinal Nerves There is a pair of spinal nerves at the level of each vertebrae for a total of 31 pairs Formed by the combination of the ventral and dorsal roots of the spinal cord Named for the region from which they arise

10 Spinal Nerves

11 PNS: Anatomy of Spinal Nerves
Spinal nerves divide soon after leaving the spinal cord Dorsal rami—serve the skin and muscles of the posterior trunk Ventral rami—form a complex of networks (plexus) for the anterior The rami, like spinal nerves, contain both motor and sensory fibers

12 Nerve Plexuses The ventral rami also form complex networks of nerves called plexuses Plexuses serve the motor and sensory needs of the limbs.

13 PNS: Spinal Nerve Plexuses

14 PNS: Spinal Nerve Plexuses

15 PNS: Distribution of Major Peripheral Nerves of the Upper and Lower Limbs

16 PNS: Distribution of Major Peripheral Nerves of the Lower Limbs

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