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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