The peripheral nervous system has both cranial and spinal nerves. Cranial nerves arise from the brain and connect to organs, muscles, and skin. Spinal nerves arise from the spinal cord and also connect to organs, muscles, and skin. Peripheral nerves can be sensory, motor, or mixed. Examples of cranial nerves include the trigeminal nerve which is mixed and innervates parts of the face, and the facial nerve which is also mixed and innervates muscles of facial expression. Spinal nerves form plexuses like the brachial plexus which innervates the arm. The autonomic nervous system regulates involuntary functions and has sympathetic and parasympathetic divisions.

1. Chapter 11 Peripheral Nervous System

2. Peripheral Nervous System Cranial nerves arising from the brain Connect to the skin and skeletal muscles Connect to viscera(organs) Spinal nerves arising from the spinal cord Connect to the skin and skeletal muscles Connecting to viscera(organs)

3. Structure of a Peripheral Nerve

4. Nerve Fiber Classification Sensory Nerves – conduct impulses into CNS Motor Nerves – conduct impulses to muscles or glands Mixed Nerves – contain both sensory nerve fibers and motor nerve fibers; most nerves

5. Cranial Nerves

6. Cranial Nerves I and II Olfactory (I) sensory smell Optic (II) sensory vision

7. Cranial Nerves III and IV Trochlear (IV) primarily motor motor impulses to muscles that move the eyes Oculomotor (III) primarily motor motor impulses to muscles that raise eyelids move the eyes focus lens adjust light entering eye

8. Cranial Nerve V Trigeminal (V) mixed (both) opthalmic division sensory from surface of eyes, tear glands, scalp, forehead, and upper eyelids maxillary division sensory from upper teeth, upper gum, upper lip, palate, and skin of face mandibular division sensory from scalp, skin of jaw, lower teeth, lower gum, and lower lip motor to muscles of mastication and muscles in floor of mouth

9. Muscles of Mastication

10. Cranial Nerves VI and VII Abducens (VI) primarily motor motor impulses to muscles that move the eyes Facial (VII) mixed (both) sensory from taste receptors motor to muscles of facial expression, tear glands, and salivary glands

11. Muscles of Facial Expression

12. Cranial Nerves VIII and IX Vestibulocochlear (VIII) aka Auditory sensory sensory from equilibrium receptors of ear (balance) sensory from hearing receptors Glossopharyngeal (IX) mixed (both) sensory from pharynx, tonsils, tongue, and carotid arteries motor to salivary glands and muscles of pharynx

13. Cranial Nerve X Vagus (X) mixed (both) motor to muscles of speech and swallowing motor to viscera of thorax and abdomen sensory from pharynx, larynx, esophagus, and viscera of thorax and abdomen

14. Cranial Nerves XI and XII Accessory (XI) Aka Spinal Accessory primarily motor motor to muscles of soft palate, pharynx, larynx, neck (sternocleidomastoid), and back (trapezius) Hypoglossal (XII) primarily motor motor to muscles of the tongue

15. Spinal Nerves mixed nerves 31 pairs 8 cervical (C1 to C8) 12 thoracic (T1 to T12) 5 lumbar (L1 to L5) 5 sacral (S1 to S5) 1 coccygeal (Co)

16. Dermatome an area of skin that the sensory nerve fibers of a particular spinal nerve innervate

17. Cervical Plexus Nerve plexus – complex networks formed by anterior branches of spinal nerves; fibers of various spinal nerves are sorted and recombined Cervical Plexus C1-C4 lies deep in the neck supply muscles and skin of the neck contribute to phrenic nerve

18. Brachial Plexus C5-T1 lies deep within shoulders musculocutaneous nerves biceps brachii; brachialis ulnar nerves “ funny bone” flexor carpi ulnaris median nerves flexor carpi radialis radial nerves posterior muscles triceps brachii extensors axillary nerves deltoid

19. Muscles That Move the Forearm

20. Muscles That Move the Hand

21. Lumbosacral Plexus T12 – S5 obturator nerves supply adductors of thighs femoral nerves supply muscles and skin of quads and sartorius tibial nerves supply posterior leg muscles; hams, calves sciatic nerves longest and largest nerve of the body

22. Muscles That Move the Thigh

23. Muscles That Move the Leg

24. Muscles That Move the Foot

25. Autonomic Nervous System functions without conscious effort controls visceral activities regulates smooth muscle, cardiac muscle, and glands Two Divisions sympathetic – prepares body for fight or flight situations parasympathetic – prepares body for resting and digesting activities

26. Sympathetic Division

27. Parasympathetic Division

28. Control of Autonomic Activity Controlled largely by CNS Medulla oblongata regulates cardiac, vasomotor and respiratory activities Hypothalamus regulates visceral functions Cerebral cortex control emotional responses