The Peripheral Nervous System The Spinal Nerves The

The Peripheral Nervous System The Spinal Nerves & The Cranium Nerves Angelina, Eden, Titus, Joey, Gabe. Ana

The Peripheral Nervous System • The peripheral nervous system (PNS) is the link between the nucleus of the central nervous system (CNS) and the rest of the body • Motor and information commands are carried by axons of the PNS • Axons bundle together and wrapped in connective tissue, to form peripheral nerves or simply nerves

• Cell bodies are clustered together in masses called ganglia • The PNS also contains both the cell bodies and the axons of sensory neurons and motor neurons of the autonomic nervous system Origination: § Cranial nerves- Brain §Spinal Nerves- Spinal cord

The Cranial Nerves Distribution and function of cranial nerves • Each nerve is classified as primarily sensory, primarily motor or mixed (sensory and motor) • 12 pairs of control nerves connect to the brain • Each nerves has a name related to its appearance or function

12 Nerves Trochlear nerve (IV) Abducens nerve (VI) Vestibulocochlear (acoustic) nerve (VIII) Vagus nerve (X) Accessory (spinal accessory) nerve (XI) Olfactory bulb nerve, NI Olfactory tract Optic nerve (II) Oculomotor nerve (III) Trigeminal nerve (V) Facial Nerve (VII) Gloss- pharyngeal nerve (IX) Hypoglossal nerve (XII)

Few people are able to remember the names, numbers and functions of the cranial nerves without some effort. Many people use mnemonic phrases such as “Oh, Once One Takes The Anatomy Final, Vacations Are Heavenly”

• Olfactory nerves- only cranial nerves attached to the cerebellum (Special sensory) • Optic nerves- carry visual information from the eyes • Oculomotor nerves- innervates four of the six muscles that move an eyeball (motor) • Trochlear nerves- smallest of nerves innervate the superior oblique muscles of the eye (motor)

• Trigeminal nerves- chewing muscles (motor); orbital structures, nasal cavity, nose, lips, teeth, palate and pharynx (sensory) • Abducens nerves- abducts the eyeball, causing it to rotate laterally, away from midline of the body • Facial nerves- controls tear glands and salivary glands • Vestibulochochlear nerves- also called acoustic nerves monitor the sensory receptors of the inner ear

• Glossopharyngeal nerves- are mixed nerves innervating the tongue and pharynx (mixed) • Vagus nerves- sensory info. to ear canals, diaphragm, taste receptors (mixed) • Accessory nerve- voluntary muscles of palate, pharynx, and larynx; sternocleidomastoid and trapezius muscles (motor) • Hypoglossal nerves- tongue muscles (motor)

The Spinal Nerves • 31 pairs of spinal nerves are grouped according to the region of the vertebral column from which they originate ü ü ü 8 pairs of cervical nerves 12 pairs of thoracic nerves 5 pairs of lumbar nerves 5 pairs sacral nerves 1 pair of coccygeal nerves

Cervical Plexus Brachial Plexus Lumbar Plexus Sacral plexus • Each pair of spinal nerves monitors a specific region of the body surface known as a dermatome

5 Questions 1. What’s the topic about? 2. How many pairs of spinal nerves are grouped according to the region of the vertebral column from which they originated ? 3. What is dermatome? 4. How many pairs of cranial nerves connect to the brain? 5. True or false? Each cranial nerve has a name related to its appearance only.