Peripheral Nervous System Lecture 5 Chapter 7 Peripheral

Peripheral Nervous System Lecture 5: Chapter 7

Peripheral Nervous System • Outside central nervous system • Contains cranial and spinal nerves

Nerve • Bundle of neuron fibers found outside of CNS – Cranial nerves • Primarily serve head and neck • 12 pairs – Spinal nerves • 31 pairs • Extend from spinal cord • Form plexuses (complex networks of nerves)

Olfactory • Cranial nerve I • Carries impulses for sense of smell

Optic • Cranial nerve II • Carries impulses for vision

Oculomotor • Cranial nerve III • Sends message to move eyeball and eyelid and to muscles that control lens shape and pupil size

Trochlear • Cranial nerve IV • Controls external eye muscle

Trigeminal • Cranial nerve V • Activates chewing muscles • Conducts sensory impulses from skin of face and mucosa of nose and mouth

Abducens • Cranial nerve VI • Controls muscle that rolls eye laterally

Facial • • Cranial nerve VII Controls muscles for facial expressions Controls lacrimal and salivary glands Carries sensory impulses from taste buds at anterior portion of tongue

Vestibulocochlear • Cranial nerve VIII • Transmits impulse of sound and balance

Glossopharyngeal • Cranial nerve IX • Promote swallowing and saliva production • Carries impulse for sense of taste from posterior taste buds on tongue

Vagus • Cranial nerve X • Parasympathetic fibers that promote digestive activity and help regulate heart activity • Control pharynx, larynx, and abdominal and thoracic viscera

Accessory • Cranial nerve XI • Activate sternocleidomastoid and trapezius muscles

Hypoglossal • Cranial nerve XII • Control tongue movement • Sensory impulses from tongue

Spinal Nerve Plexuses • 4 plexuses – Cervical – Brachial – Lumbar – Sacral

Cervical plexus • Originates from cervical region of spinal cord • Controls diaphragm and muscles of neck and shoulders

Brachial plexus • provides connections to the shoulders, upper arms, forearms, and hands – Important nerves • Axillary • Radial • ulnar

Lumbar plexus • provides connections to the back, abdomen, groin, thighs, buttock, and knees. – Important nerves • Femoral • Obturator

Sacral plexus • provides connections to the pelvis, buttocks, genitals, thighs, calves, and feet • Important nerves: – Sciatic (largest nerve in body)- splits into peroneal and tibial nerves – Superior and inferior gluteal