Chapter 9

The Peripheral and Autonomic Nervous System

Edited by Dr. Ryan Lambert-Bellacov

Peripheral Nervous System

• Nerves that connect the brain and spinal cord with sensory receptors, muscles, and glands

• Afferent peripheral system

• Efferent peripheral system

Efferent Peripheral System

• Somatic nervous system

• Autonomic nervous system– Sympathetic

– Parasympathetic

Edited by Dr. Ryan Lambert-Bellacov

Neuron AnatomyNeuron Anatomy

Slide 7.9b

Cell body

Nucleus

Large nucleolus

Figure 7.4a

Edited by Dr. Ryan Lambert-Bellacov

Nerves • Bundles of nerve fibers enclosed by

connective tissue– Sensory or afferent nerves

– Motor or efferent nerves

– Mixed nerves

Neuron ClassificationNeuron Classification

Slide 7.15

Figure 7.6

Neuron Cell Body LocationNeuron Cell Body Location

Slide 7.13

Most are found in the central nervous system

Gray matter – cell bodies and unmylenated fibers

Nuclei – clusters of cell bodies within the white matter of the central nervous system

Ganglia – collections of cell bodies outside the central nervous system

How Neurons Function How Neurons Function (Physiology)(Physiology)

Slide 7.17

Irritability – ability to respond to stimuli

Conductivity – ability to transmit an impulse

The plasma membrane at rest is polarized

Fewer positive ions are inside the cell than outside the cell

Starting a Nerve ImpulseStarting a Nerve Impulse

Slide 7.18Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Depolarization – a stimulus depolarizes the neuron’s membrane

A deploarized membrane allows sodium (Na+) to flow inside the membrane

The exchange of ions initiates an action potential in the neuron

Figure 7.9a–c

The Action PotentialThe Action Potential

Slide 7.19Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

If the action potential (nerve impulse) starts, it is propagated over the entire axon

Potassium ions rush out of the neuron after sodium ions rush in, which repolarizes the membrane

The sodium-potassium pump restores the original configuration This action requires ATP

Nerve Impulse PropagationNerve Impulse Propagation

Slide 7.20

The impulse continues to move toward the cell body

Impulses travel faster when fibers have a myelin sheath

Figure 7.9c–e

How Neurons Communicate at How Neurons Communicate at SynapsesSynapses

Slide 7.22Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 7.10

The Reflex ArcThe Reflex Arc

Slide 7.23Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Reflex – rapid, predictable, and involuntary responses to stimuli

Reflex arc – direct route from a sensory neuron, to an interneuron, to an effector

Figure 7.11a

Simple Reflex ArcSimple Reflex Arc

Slide 7.24Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 7.11b, c

Types of Reflexes and RegulationTypes of Reflexes and Regulation

Slide 7.25Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Autonomic reflexes

Smooth muscle regulation

Heart and blood pressure regulation

Regulation of glands

Digestive system regulation

Somatic reflexes

Activation of skeletal muscles

Cranial and Spinal Nerves

• Part of the peripheral nervous system

• 12 pairs of cranial nerves

• 31 pairs of spinal nerves– Direct connection

– Plexus

Sensory and Motor Areas of the Sensory and Motor Areas of the Cerebral CortexCerebral Cortex

Slide 7.31

Figure 7.14

Cranial Nerves

• I– Olfactory

• II– Optic

• III– Oculomotor

• IV– Trochlear

Edited by Dr. Ryan Lambert-Bellacov

Cranial Nerves

• V– Trigeminal

• VI– Abducens

• VII– Facial

• VIII– Vestibulocochlear

Edited by Dr. Ryan Lambert-Bellacov

Cranial Nerves

• IX– Glossopharyngeal

• X– Vagus

• XI– Spinal accessory

• XII– Hypoglossal

Edited by Dr. Ryan Lambert-Bellacov

Spinal Nerve Plexus

• Cervical plexus

• Brachial plexus

• Lumbar plexus

• Sacral plexus

Edited by Dr. Ryan Lambert-Bellacov

Autonomic Nervous System

• Nerves, ganglia, and• plexuses which carry

impulses to all smooth• muscle, secretory

glands, and heart muscle• Sympathetic system• Parasympathetic system• Strongly influenced by • emotion

Sympathetic System

• Consists primarily of two cords, beginning at the base of the brain and proceeding down both sides of the spinal column

• Fight or flight system

Sympathetic System

• Learning to cope with stress is essential to preventing over stimulation of this system and the subsequent problems

– It was meant for acute stress, not chronic stress

Parasympathetic System

• Vagus nerve

• Pelvic nerves

• Counteracts effects of the sympathetic nervous system

Biofeedback

• Measurement of physiological responses

• Yields information about the relationships between the mind and the body

• Can learn to manipulate these responses through mental activity

Types of Anesthesia

• Local numbing of area

• Regional anesthesia– Spinal anesthesia

– Epidural anesthesia

– Nerve blocks

• General anesthesia

Disorders

• Neuritis

• Peripheral neuropathy

• Sciatica

Edited by Dr. Ryan Lambert-Bellacov

Disorders

• Trigeminal neuralgia

• Bell’s palsy

• Shingles or herpes zoster

• Carpal tunnel syndrome

Edited by Dr. Ryan Lambert-Bellacov

Specialized Area of the CerebrumSpecialized Area of the Cerebrum

Slide 7.32a

Cerebral areas involved in special senses

Gustatory area (taste)

Visual area

Auditory area

Olfactory area

Edited by Dr. Ryan Lambert-Bellacov