Peripheral Nervous System Chapter 14

I. Spinal Nerves A. Overview Have 31 pairs #’d by attachment site to spinal cord (C3, L2, etc) All are “mixed” nerves (carry both sensory & motor info)

I. Spinal Nerves B. Branching Networks Attached to spinal cord by 2 “roots” These form networks called plexuses

I. Spinal Nerves 4 major plexuses Cervical Brachial Lumbar Sacral B. Branching Networks 4 major plexuses Cervical Brachial Lumbar Sacral

I. Spinal Nerves B. Branching Networks Areas of skin supplied by sensory fibers from same nerve = dermatome Areas supplied by motor fibers from same nerve = myotome

II. Somatic Senses Detect stimuli from internal & external sources A. Sensory Receptors Detect stimuli from internal & external sources Receptors are specialized dendritic endings Receptors exhibit “adaptation” – magnitude of message decreases over time if signal is continuous Example: smell of perfume

II. Somatic Senses Widely distributed B. Distribution of Receptors Widely distributed Found in skin, mucosa, connective tissues, muscles, tendons, joints, viscera Not uniform; some sites have many, others have few

II. Somatic Senses Classification by Stimulus Detected C. Classification of Receptors Classification by Stimulus Detected Mechanoreceptors Detect motion (incl. pressure & stretch) Chemoreceptors Detect chemicals (amounts or changes in amts) Thermoreceptors Detect changes in temperature Nociceptors Detect pain Photoreceptors Detect light

II. Somatic Senses Classification by Location C. Classification of Receptors Classification by Location Exteroceptors On or near body surface Usually respond to external stimuli Interoceptors (visceroceptors) Often within viscera (body organs) Usually detect pressure, chemical changes, etc. Proprioceptors Within skeletal muscles and tendons Info about body motion, location, orientation

Reminder: Peripheral NS divided into… Somatic Autonomic Msgs to/from skeletal muscles Reflexes move through reflex arc Autonomic Msgs to/from glands, smooth muscles, cardiac muscle Has sympathetic & parasympathetic divisions

III. Cranial Nerves A. Overview 12 pairs; Connected to brain (mostly to brainstem) May be sensory, motor, or mixed

Mnemonic Devices To remember the order of the nerves: “Oh, oh, oh, to touch and feel very good velvet, ah!” To remember the type of nerves: Some say marry money but my brother says big brains matter more

III. Cranial Nerves B. Nerve Pairs 1. Olfactory Sensory Sense of Smell

III. Cranial Nerves B. Nerve Pairs 2. Optic Sensory Vision

III. Cranial Nerves B. Nerve Pairs 3. Oculomotor Motor Eye movement Pupil size 4. Trochlear

III. Cranial Nerves B. Nerve Pairs 5. Trigeminal Both (Mixed) Sensation in head/face Chewing

III. Cranial Nerves B. Nerve Pairs 6. Abducens Motor Moves eye to side

III. Cranial Nerves B. Nerve Pairs 7. Facial Both (Mixed) Sense of taste Facial expression Saliva & tear secretion

III. Cranial Nerves B. Nerve Pairs 8. Vestibulocochlear Sensory Hearing Balance and equilibrium

III. Cranial Nerves B. Nerve Pairs 9. Glossopharyngeal Both (Mixed) Senses of tongue Swallowing motions Saliva secretion

III. Cranial Nerves B. Nerve Pairs 10. Vagus Both (Mixed) Senses & movements of visceral organs

III. Cranial Nerves B. Nerve Pairs 11. Accessory Motor Shoulder & head movement

III. Cranial Nerves B. Nerve Pairs 12. Hypoglossal Motor Tongue movement

Self-Quiz: Cranial Nerves Make a chart…# 1-12 # Nerve Type Function(s) 1 2 3 4 … 12

Name the cranial nerves: 1. O 2. O 3. O 4. T 5. T 6. A 7. F 8. V 9. G 10. V 11. A 12. H

Name the cranial nerves: 1. Olfactory 2. Optic 3. Oculomotor 4. Trochlear 5. Trigeminal 6. Abducens 7. Facial 8. Vestibulocochlear 9. Glossopharyngeal 10. Vagus 11. Accessory 12. Hypoglossal Which are sensory only? Which are motor only? Which are both (mixed)?

Name the cranial nerves: 1. Olfactory - S 2. Optic - S 3. Oculomotor - M 4. Trochlear - M 5. Trigeminal - B 6. Abducens - M 7. Facial - B 8. Vestibulocochlear - S 9. Glossopharyngeal - B 10. Vagus - B 11. Accessory - M 12. Hypoglossal - M Which are for eye movement?

Name the cranial nerves: 1. Olfactory - S 2. Optic - S 3. Oculomotor - M 4. Trochlear - M 5. Trigeminal - B 6. Abducens - M 7. Facial - B 8. Vestibulocochlear - S 9. Glossopharyngeal - B 10. Vagus - B 11. Accessory - M 12. Hypoglossal - M Which is for vision? For hearing? For smelling?

Name the cranial nerves: 1. Olfactory - S 2. Optic - S 3. Oculomotor - M 4. Trochlear - M 5. Trigeminal - B 6. Abducens - M 7. Facial - B 8. Vestibulocochlear - S 9. Glossopharyngeal - B 10. Vagus - B 11. Accessory - M 12. Hypoglossal - M Which 2 deal with your face and mouth? Which is facial movement/taste? Which is facial sensation/chewing?

Name the cranial nerves: 1. Olfactory - S 2. Optic - S 3. Oculomotor - M 4. Trochlear - M 5. Trigeminal - B 6. Abducens - M 7. Facial - B 8. Vestibulocochlear - S 9. Glossopharyngeal - B 10. Vagus - B 11. Accessory - M 12. Hypoglossal - M Which one is “out of state”? Which body parts are affected by it?

Name the cranial nerves: 1. Olfactory - S 2. Optic - S 3. Oculomotor - M 4. Trochlear - M 5. Trigeminal - B 6. Abducens - M 7. Facial - B 8. Vestibulocochlear - S 9. Glossopharyngeal - B 10. Vagus - B 11. Accessory - M 12. Hypoglossal - M Which 2 deal with your tongue movements? Which of these also deals with tongue sensation?

Name the cranial nerves: 1. Olfactory - S 2. Optic - S 3. Oculomotor - M 4. Trochlear - M 5. Trigeminal - B 6. Abducens - M 7. Facial - B 8. Vestibulocochlear - S 9. Glossopharyngeal - B 10. Vagus - B 11. Accessory - M 12. Hypoglossal - M What does the last nerve move?

The End