Chapter 10 THE NERVOUS SYSTEM INTRODUCTION SPINAL CORD

Introduction • Control center and communication network – Directs functions of body’s organs and

Introduction (cont’d. ) • Homeostasis: balanced internal environment – Controlled by nervous and endocrine

ORGANIZATION © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied,

Organization (cont’d. ) • Central nervous system: brain and spinal cord • Peripheral nervous

Organization (cont’d. ) © 2012 Delmar Cengage Learning. All Rights Reserved. May not be

CLASSIFICATION OF NERVE CELLS © 2012 Delmar Cengage Learning. All Rights Reserved. May not

Neuroglia Cells • Astrocytes: support, connection, blood brain barrier • Oligodendroglia: support, myelin sheath

Neuroglia Cells (cont’d. ) • Schwann: myelin sheaths in peripheral nervous system © 2012

The Structure of a Neuron • Cell body • Dendrites: receptive areas • Axon:

The Structure of a Neuron (cont’d. ) © 2012 Delmar Cengage Learning. All Rights

The Structure of a Neuron (cont’d. ) • Multipolar: several dendrites coming off cell

The Structure of a Neuron (cont’d. ) • Receptors: detect environmental stimuli • Sensory:

THE PHYSIOLOGY OF THE NERVE IMPULSE © 2012 Delmar Cengage Learning. All Rights Reserved.

The Physiology of the Nerve Impulse (cont’d. ) • Nerve cell fiber resting potential

The Physiology of the Nerve Impulse (cont’d. ) • Depolarization: Na+ rush inside cell

THE SYNAPTIC TRANSMISSION © 2012 Delmar Cengage Learning. All Rights Reserved. May not be

The Synaptic Transmission (cont’d. ) • Synapse: axon terminal branches close to next dendrites

The Synaptic Transmission (cont’d. ) • Neurotransmitters – Acetylcholine • Most common – Epinephrine

Animation – Firing of Neurotransmitters • This animation illustrates the physiology of the nerve

THE REFLEX ARC © 2012 Delmar Cengage Learning. All Rights Reserved. May not be

The Reflex Arc (cont’d. ) • Knee-jerk reflex • Maintain homeostasis – Heartbeat/breathing rates

The Reflex Arc (cont’d. ) • Maintain homeostasis – Swallowing – Vomiting © 2012

The Reflex Arc (cont’d. ) • Involuntary reaction to external stimulus © 2012 Delmar

GROUPING OF NEURAL TISSUE © 2012 Delmar Cengage Learning. All Rights Reserved. May not

Grouping of Neural Tissue (cont’d. ) • White matter – Groups of myelinated axons

Grouping of Neural Tissue (cont’d. ) • • Nerve: bundle of fibers outside CNS

THE SPINAL CORD © 2012 Delmar Cengage Learning. All Rights Reserved. May not be

Introduction • Continuation of medulla oblongata • 31 segments each with pair of spinal

Spinal Cord © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned,

Functions of the Spinal Cord • Conveys sensory impulses to the brain • Integrates

THE SPINAL NERVES © 2012 Delmar Cengage Learning. All Rights Reserved. May not be

The Spinal Nerves (cont’d. ) • All 31 pairs arise from union of dorsal

The Spinal Nerves (cont’d. ) • Named and numbered according to region and level

Summary • Named the major division of the nervous system • Classified neurons and

Summary (cont’d. ) • Discussed the structure of the spinal cord • Named the

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Chapter 10 THE NERVOUS SYSTEM: INTRODUCTION, SPINAL CORD, AND SPINAL NERVES © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Introduction • Control center and communication network – Directs functions of body’s organs and systems – Interprets external environment – Determines reaction to change © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Introduction (cont’d. ) • Homeostasis: balanced internal environment – Controlled by nervous and endocrine systems © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Organization (cont’d. ) • Central nervous system: brain and spinal cord • Peripheral nervous system – Afferent peripheral system • Sensory neurons – Efferent peripheral system • Somatic • Autonomic - sympathetic and parasympathetic © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Neuroglia Cells • Astrocytes: support, connection, blood brain barrier • Oligodendroglia: support, myelin sheath formation • Microglial: phagocytosis • Ependymal: line the ventricles of the brain © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Neuroglia Cells (cont’d. ) • Schwann: myelin sheaths in peripheral nervous system © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

The Structure of a Neuron • Cell body • Dendrites: receptive areas • Axon: extension of cell body – Schwann cells – Nodes of Ranvier © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

The Structure of a Neuron (cont’d. ) • Multipolar: several dendrites coming off cell body • Bipolar: one dendrite and one axon • Unipolar: one process extending from cell body © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

The Structure of a Neuron (cont’d. ) • Receptors: detect environmental stimuli • Sensory: receive impulse from receptor site • Internuncial: transmit impulse for interpretation and processing • Motor: reaction to the stimulus © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

The Physiology of the Nerve Impulse (cont’d. ) • Nerve cell fiber resting potential – Na+ concentration higher on outside – K+ concentration higher on inside – Negative charge on inside – Positive charge on outside © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

The Physiology of the Nerve Impulse (cont’d. ) • Depolarization: Na+ rush inside cell • Repolarization: K+ rush out to restore balance • Depolarization: Repolarization moves in one direction • Myelinated vs. unmyelinated • All-or-none law © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

The Synaptic Transmission (cont’d. ) • Synapse: axon terminal branches close to next dendrites • Impulse reaches axon terminals • Triggers neurotransmitter release into synaptic cleft © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

The Synaptic Transmission (cont’d. ) • Neurotransmitters – Acetylcholine • Most common – Epinephrine – Norepinephrine – Serotonin – Dopamine – Endorphins © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Animation – Firing of Neurotransmitters • This animation illustrates the physiology of the nerve impulse Click Here to Play Firing of Neurotransmitters Animation © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

The Reflex Arc (cont’d. ) • Knee-jerk reflex • Maintain homeostasis – Heartbeat/breathing rates – Digestion – Coughing – Sneezing © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

The Reflex Arc (cont’d. ) • Maintain homeostasis – Swallowing – Vomiting © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

The Reflex Arc (cont’d. ) • Involuntary reaction to external stimulus © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Grouping of Neural Tissue (cont’d. ) • White matter – Groups of myelinated axons – Forms nerve tracts in CNS • Gray matter – Nerve cell bodies and dendrites – Unmyelinated axon bundles – Cortex: gray matter on surface of brain © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Grouping of Neural Tissue (cont’d. ) • • Nerve: bundle of fibers outside CNS Ganglia: nerve cell bodies outside CNS Tract: bundle of fibers inside CNS Nucleus: nerve cell bodies and dendrites inside CNS • Horns: areas of gray matter in spinal cord © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Introduction • Continuation of medulla oblongata • 31 segments each with pair of spinal nerves • Protected by meninges – Dura mater – Arachnoid – Pia mater © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Functions of the Spinal Cord • Conveys sensory impulses to the brain • Integrates reflexes • Spinal nerves connect at roots – Dorsal root: sensory – Ventral root: motor © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

The Spinal Nerves (cont’d. ) • All 31 pairs arise from union of dorsal and ventral roots • Mixed nerves consisting of motor and sensory fibers • Most exit vertebral column between vertebrae © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

The Spinal Nerves (cont’d. ) • Named and numbered according to region and level of spinal cord – Cervical: 8 pairs – Thoracic: 12 pairs – Lumbar: 5 pairs – Sacral: 5 pairs – Coccygeal: 1 pair © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Summary • Named the major division of the nervous system • Classified neurons and neuroglial cells • Discussed the physiology of the nerve impulse and transmission at synapses • Named the different types of neural tissue © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Summary (cont’d. ) • Discussed the structure of the spinal cord • Named the spinal nerves © 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.