《医学生理学 Medical Physiology》参考教材资料（PDF电子书籍）Neuroscience, Third Edition, 2004

Supplements xix Images and text relevant to the textbook: Icons in the textbook indicate specific content on the CD. By entering a textbook pag number, students can automatically load the relevant images and text A history feature that allows the student to quickly reload recently viewed structures a bookmark feature that adds bookmarks to structures of in- terest; bookmarks are automatically stored on the students computer A notes feature that allows students to type no otes for ar y selected structure; notes are automatically saved on the stu- dent's computer and can be shared among students and instructors (i. e, imported and exported) A self-quiz mode that allows for testing on structure identifica tion and functional informatic A print feature that formats images and text for printed output ° An image zoom tool For the Instructor Instructors Resource CD (ISBN 0-87893-750-1) This expanded resource includes all the figures and tables from the textbook in JPEG format, reformatted and relabeled for optimal read ability. Also included are ready-to-use PowerPoint presentations of all figures and tables. In addition, new for the Third Edition, the Instructor's Resource CD includes a set of short-answer study ques tions for each chapter in Microsoft Word format Overhead Transparencies(ISBN 0-87893-751-X) This set includes 100 illustrations(approximately 150 transparencies), selected from throughout the textbook for teaching purposes. These are relabeled and optimized for projection in classrooms

• Images and text relevant to the textbook: Icons in the textbook indicate specific content on the CD. By entering a textbook page number, students can automatically load the relevant images and text. • A history feature that allows the student to quickly reload recently viewed structures. •Abookmark feature that adds bookmarks to structures of in￾terest; bookmarks are automatically stored on the student’s computer. • A notes feature that allows students to type notes for any selected structure; notes are automatically saved on the stu￾dent’s computer and can be shared among students and instructors (i.e., imported and exported). • A self-quiz mode that allows for testing on structure identifica￾tion and functional information. • A print feature that formats images and text for printed output. • An image zoom tool. For the Instructor Instructor’s Resource CD (ISBN 0-87893-750-1) This expanded resource includes all the figures and tables from the textbook in JPEG format, reformatted and relabeled for optimal read￾ability. Also included are ready-to-use PowerPoint® presentations of all figures and tables. In addition, new for the Third Edition, the Instructor’s Resource CD includes a set of short-answer study ques￾tions for each chapter in Microsoft® Word® format. Overhead Transparencies (ISBN 0-87893-751-X) This set includes 100 illustrations (approximately 150 transparencies), selected from throughout the textbook for teaching purposes. These are relabeled and optimized for projection in classrooms. Supplements xix Purves3/eFM 5/13/04 1:00 PM Page xix

Purves3/eFM 5/13/04 1:00 PM Page xx

Chapter Studying the Nervous Systems verview of humans and Neuroscience encompasses a broad range of questions about how nervous Other Animals systems are organized, and how they function to generate behavior. These questions can be explored using the analytical tools of genetics, molecular and cell biology, systems anatomy and physiology, behavioral biology, and psychology. The major challenge for a student of neuroscience is to integrate the diverse knowledge derived from these various levels of analysis into a more or less coherent understanding of brain structure and function(one has to qualify this statement because so many questions remain una swered). Many of the issues that have been explored successfully concern how the principal cells of any nervous system--neurons and glia-perform their basic functions in anatomical, electrophysiological, and molecular terms. The varieties of neurons and supporting glial cells that have been identified are assembled into ensembles called neural circuits, and these cir- cuits are the primary components of neural systems that process specific types of information. Neural systems comprise neurons and circuits in a number of discrete anatomical locations in the brain. These systems subserve one of three general functions. Sensory systems represent information about the state of the organism and its environment, motor systems organize and generate actions; and associational systems link the sensory and motor sides of the nervous system, providing the basis for"higher-order"functions such as perception, attention, cognition, emotions, rational thinking, and other complex brain functions that lie at the core of understanding human beings, their history and their future Genetics, Genomics, and the brain The recently completed sequencing of the genome in humans, mice, the frui fly Drosophila melanogaster, and the nematode worm Caenorhabditis elegans is perhaps the logical starting point for studying the brain and the rest of the nervous system; after all, this inherited information is also the starting point each individual organism. The relative ease of obtaining, analyzing, and correlating gene sequences with neurobiological observations has facilitated a wealth of new insights into the basic biology of the nervous system. In par allel with studies of normal nervous systems, the genetic analysis of human pedigrees with various brain diseases has led to a widespread sense that it will soon be possible to understand and treat disorders long considered beyond the reach of science and medicine me n gene consists of DNA sequences called exons that are transcribed into a essenger RNA and subsequently a protein. The set of exons that defines

Overview Neuroscience encompasses a broad range of questions about how nervous systems are organized, and how they function to generate behavior. These questions can be explored using the analytical tools of genetics, molecular and cell biology, systems anatomy and physiology, behavioral biology, and psychology. The major challenge for a student of neuroscience is to integrate the diverse knowledge derived from these various levels of analysis into a more or less coherent understanding of brain structure and function (one has to qualify this statement because so many questions remain unan￾swered). Many of the issues that have been explored successfully concern how the principal cells of any nervous system—neurons and glia—perform their basic functions in anatomical, electrophysiological, and molecular terms. The varieties of neurons and supporting glial cells that have been identified are assembled into ensembles called neural circuits, and these cir￾cuits are the primary components of neural systems that process specific types of information. Neural systems comprise neurons and circuits in a number of discrete anatomical locations in the brain. These systems subserve one of three general functions. Sensory systems represent information about the state of the organism and its environment, motor systems organize and generate actions; and associational systems link the sensory and motor sides of the nervous system, providing the basis for “higher-order” functions such as perception, attention, cognition, emotions, rational thinking, and other complex brain functions that lie at the core of understanding human beings, their history and their future. Genetics, Genomics, and the Brain The recently completed sequencing of the genome in humans, mice, the fruit fly Drosophila melanogaster, and the nematode worm Caenorhabditis elegans is perhaps the logical starting point for studying the brain and the rest of the nervous system; after all, this inherited information is also the starting point of each individual organism. The relative ease of obtaining, analyzing, and correlating gene sequences with neurobiological observations has facilitated a wealth of new insights into the basic biology of the nervous system. In par￾allel with studies of normal nervous systems, the genetic analysis of human pedigrees with various brain diseases has led to a widespread sense that it will soon be possible to understand and treat disorders long considered beyond the reach of science and medicine. A gene consists of DNA sequences called exons that are transcribed into a messenger RNA and subsequently a protein. The set of exons that defines Chapter 1 1 Studying the Nervous Systems of Humans and Other Animals Purves01 5/13/04 1:02 PM Page 1

2 Chapter One Figure 1.1 Estimates of the number of genes in the human genome, as well as Human in the genomes of the mouse, the fruit fly Drosophila melanogaster, and the nematode worm Caenorhabditis elegans C. elegans 10000 00O0 30000 40000 50000 Number of genes the transcript of any gene is flanked by upstream(or 5) and downstream(or 3) regulatory sequences that control gene expression. In addition, sequences between exons-called introns-further influence transcription. Of the approximately 35,000 genes in the human genome, a majority are expressed in the developing and adult brain; the same is true in mice, flies, and worms-the species commonly used in modern genetics(and increasingly in neuroscience)(Figure 1.1). Nevertheless, very few genes are uniquely ex- pressed in neurons, indicating that nerve cells share most of the basic struc tural and functional properties of other cells. Accordingly, most"brain- specific"genetic information must reside in the remainder of nucleic acid sequences-regulatory sequences and introns-that control the timing, quantity, variability and cellular specificity of gene expression. One of the most promising dividends of sequencing the human genome has been the realization that one or a few genes, when altered(mutated),can begin to explain some aspects of neurological and psychiatric diseases Before the "postgenomic era"(which began following completion of the sequencing of the human genome), many of the most devastating brain dis- ases remained largely mysterious because there was little sense of how or why the normal biology of the nervous system was compromised. The iden- tification of genes correlated with disorders such as Huntingtons disease, Parkinsons disease, Alzheimer's disease, major depression, and schizophre nia has provided a promising start to understanding these pathological processes in a much deeper way(and thus devising rational therapies Genetic and genomic information alone do not completely explain how the brain normally works or how disease processes disrupt its function. To achieve these goals it is equally essential to understand the cell biology anatomy, and physiology of the brain in health as well as disease The Cellular Components of the Nervous System Early in the nineteenth century, the cell was recognized as the fundamental unit of all living organisms. It was not until well into the twentieth century, however, that neuroscientists agreed that nervous tissue, like all other organs, is made up of these fundamental units. The major reason was that the first generation of "modern"neurobiologists in the nineteenth century had difficulty resolving the unitary nature of nerve cells with the micro- scopes and cell staining techniques that were then available. This inade-

2 Chapter One Figure 1.1 Estimates of the number of genes in the human genome, as well as in the genomes of the mouse, the fruit fly Drosophila melanogaster, and the nematode worm Caenorhabditis elegans. the transcript of any gene is flanked by upstream (or 5′) and downstream (or 3′) regulatory sequences that control gene expression. In addition, sequences between exons—called introns—further influence transcription. Of the approximately 35,000 genes in the human genome, a majority are expressed in the developing and adult brain; the same is true in mice, flies, and worms—the species commonly used in modern genetics (and increasingly in neuroscience) (Figure 1.1). Nevertheless, very few genes are uniquely ex￾pressed in neurons, indicating that nerve cells share most of the basic struc￾tural and functional properties of other cells. Accordingly, most “brain￾specific” genetic information must reside in the remainder of nucleic acid sequences—regulatory sequences and introns—that control the timing, quantity, variability and cellular specificity of gene expression. One of the most promising dividends of sequencing the human genome has been the realization that one or a few genes, when altered (mutated), can begin to explain some aspects of neurological and psychiatric diseases. Before the “postgenomic era” (which began following completion of the sequencing of the human genome), many of the most devastating brain dis￾eases remained largely mysterious because there was little sense of how or why the normal biology of the nervous system was compromised. The iden￾tification of genes correlated with disorders such as Huntington’s disease, Parkinson’s disease, Alzheimer’s disease, major depression, and schizophre￾nia has provided a promising start to understanding these pathological processes in a much deeper way (and thus devising rational therapies). Genetic and genomic information alone do not completely explain how the brain normally works or how disease processes disrupt its function. To achieve these goals it is equally essential to understand the cell biology, anatomy, and physiology of the brain in health as well as disease. The Cellular Components of the Nervous System Early in the nineteenth century, the cell was recognized as the fundamental unit of all living organisms. It was not until well into the twentieth century, however, that neuroscientists agreed that nervous tissue, like all other organs, is made up of these fundamental units. The major reason was that the first generation of “modern” neurobiologists in the nineteenth century had difficulty resolving the unitary nature of nerve cells with the micro￾scopes and cell staining techniques that were then available. This inade￾Number of genes 0 10,000 20,000 30,000 40,000 50,000 Human Mouse D. melanogaster C. elegans Purves01 5/13/04 1:02 PM Page 2

Studying the Nervous Systems of Humans and Other Animals 3 (A)Neurons in mesencephalic(B)Retinal (C) Retinal ganglion cell D)Retinal amacrine cell nucleus of cranial nerve v endrites<s> Dendrites Dendrites Cell body- Cell bod A Axons (E) Cortical pyramidal cell F)Cerebellar Purkinje cells Dendrites dy A Axon Figure 1.2 Examples of the rich variety of nerve cell morphologies found in the quacy was exacerbated by the extraordinarily complex shapes and extensive from actual nerve cells stained by branches of individual nerve cells, which further obscured their resemblance impregnation with silver salts(the so- to the geometrically simpler cells of other tissues(Figures 1.2-1.4).As a called Golgi technique, the method used result, some biologists of that era concluded that each nerve cell was con- in the classical studies of Golgi and nected to its neighbors by protoplasmic links, forming a continuous nerve Cajal ). Asterisks indicate that the axon ell network, or reticulum. The "reticular theory"of nerve cell communica- runs on much farther than shown. Note tion,which was championed by the Italian neuropathologist Camillo Golgi that some cells, like the retinal bipolar and was replaced by what came to be known as the"neuron doctrine. "The others, like the retinal amacrine cell. major proponents of this new perspective were the Spanish neuroanatomist have no axon at all. The drawings are Santiago Ramon y Cajal and the British physiologist Charles Sherrington. not all at the same scale e The contrasting views represented by Golgi and Cajal occasioned a spir- ed debate in the early twentieth century that set the course of modern neu roscience. Based on light microscopic examination of nervous tissue stained with silver salts according to a method pioneered by Golgi, Cajal argued persuasively that nerve cells are discrete entities, and that they communicate

quacy was exacerbated by the extraordinarily complex shapes and extensive branches of individual nerve cells, which further obscured their resemblance to the geometrically simpler cells of other tissues (Figures 1.2–1.4). As a result, some biologists of that era concluded that each nerve cell was con￾nected to its neighbors by protoplasmic links, forming a continuous nerve cell network, or reticulum. The “reticular theory” of nerve cell communica￾tion, which was championed by the Italian neuropathologist Camillo Golgi (for whom the Golgi apparatus in cells is named), eventually fell from favor and was replaced by what came to be known as the “neuron doctrine.” The major proponents of this new perspective were the Spanish neuroanatomist Santiago Ramón y Cajal and the British physiologist Charles Sherrington. The contrasting views represented by Golgi and Cajal occasioned a spir￾ited debate in the early twentieth century that set the course of modern neu￾roscience. Based on light microscopic examination of nervous tissue stained with silver salts according to a method pioneered by Golgi, Cajal argued persuasively that nerve cells are discrete entities, and that they communicate Studying the Nervous Systems of Humans and Other Animals 3 Axon Cell body Dendrites Dendrites (C) Retinal ganglion cell (F) Cerebellar Purkinje cells Axon Cell body (A) Neurons in mesencephalic nucleus of cranial nerve V Axons * * Cell bodies (B) Retinal bipolar cell Dendrites Dendrites Cell body Axon Cell body Axon Cell body Dendrites (D) Retinal amacrine cell (E) Cortical pyramidal cell * * Figure 1.2 Examples of the rich variety of nerve cell morphologies found in the human nervous system. Tracings are from actual nerve cells stained by impregnation with silver salts (the so￾called Golgi technique, the method used in the classical studies of Golgi and Cajal). Asterisks indicate that the axon runs on much farther than shown. Note that some cells, like the retinal bipolar cell, have a very short axon, and that others, like the retinal amacrine cell, have no axon at all. The drawings are not all at the same scale. Purves01 5/13/04 1:02 PM Page 3