LANGE N USMLE ROAD MAP NEUROSCIENCE Second Edition JAMES S. WHITE, PhD Adjunct Assistant Professor of Cell and Developmental Biology University of Pennsylvania School of Medicine Philadelphia, Pennsylvania Assistant Professor of Cell Biology School of Osteopathic Medicine University of Medicine and Dentistry of New Jersey Stratford, New Jersey New York Chicago San Francisco Lisbon London Madrid Mexico City Milan New Delhi San Juan Seoul Singapore Sydney Toronto Copyright © 2008 by The McGraw-Hill Companies, Inc. All rights reserved. Manufactured in the United States of America. Except as permitted under the United States Copyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written permission of the publisher. 0-07-164306-0 The material in this eBook also appears in the print version of this title: 0-07-149623-8. All trademarks are trademarks of their respective owners. Rather than put a trademark symbol after every occurrence of a trademarked name, we use names in an editorial fashion only, and to the benefit of the trademark owner, with no intention of infringement of the trademark. Where such designations appear in this book, they have been printed with initial caps. McGraw-Hill eBooks are available at special quantity discounts to use as premiums and sales promotions, or for use in corporate training programs. For more information, please contact George Hoare, Special Sales, at [email protected] or (212) 904-4069. TERMS OF USE This is a copyrighted work and The McGraw-Hill Companies, Inc. (“McGraw-Hill”) and its licensors reserve all rights in and to the work. Use of this work is subject to these terms. Except as permitted under the Copyright Act of 1976 and the right to store and retrieve one copy of the work, you may not decompile, disassemble, reverse engineer, reproduce, modify, create derivative works based upon, trans- mit, distribute, disseminate, sell, publish or sublicense the work or any part of it without McGraw-Hill’s prior consent. You may use the work for your own noncommercial and personal use; any other use of the work is strictly prohibited. Your right to use the work may be terminated if you fail to comply with these terms. THE WORK IS PROVIDED “AS IS.” McGRAW-HILL AND ITS LICENSORS MAKE NO GUARANTEES OR WARRANTIES AS TO THE ACCURACY, ADEQUACY OR COMPLETENESS OF OR RESULTS TO BE OBTAINED FROM USING THE WORK, INCLUDING ANY INFORMATION THAT CAN BE ACCESSED THROUGH THE WORK VIA HYPERLINK OR OTHERWISE, AND EXPRESSLY DISCLAIM ANY WARRANTY, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. McGraw-Hill and its licensors do not warrant or guarantee that the functions contained in the work will meet your requirements or that its operation will be uninterrupted or error free. Neither McGraw-Hill nor its licensors shall be liable to you or anyone else for any inaccuracy, error or omission, regardless of cause, in the work or for any damages resulting therefrom. McGraw-Hill has no responsibility for the content of any information accessed through the work. Under no circumstances shall McGraw-Hill and/or its licensors be liable for any indirect, incidental, special, punitive, consequential or similar damages that result from the use of or inability to use the work, even if any of them has been advised of the possibility of such damages. This limitation of liability shall apply to any claim or cause whatsoever whether such claim or cause arises in contract, tort or otherwise. DOI: 10.1036/0071496238 Professional Want to learn more? We hope you enjoy this McGraw-Hill eBook! If you’d like more information about this book, its author, or related books and websites, please click here. For more information about this title, click here CONTENTS Using the Road Map Series for Successful Review . vii Acknowledgments . ix 1. Development, Gross Anatomy, and Blood Supply of the Nervous System . 1 Central and Peripheral Nervous Systems (CNS, PNS) 1 Development of Nervous System 3 The Major Components of the CNS 8 Arterial Blood Supply of the CNS 11 Stroke and its Causes 16 Arterial Blood Supply of the Spinal Cord 19 Venous Drainage of the CNS and Intracranial Bleeds 20 Circumventricular Organs 21 Ventricular System 22 Clinical Problems 25 Matching Problems 29 Answers 31 2. Cytology of the Nervous System . 33 Neurons 33 Axonal Transport 37 Synaptic Terminals 39 Chemical Neurotransmission 41 Neurotransmitter Receptors 45 Glial and Supporting Cells in the CNS and PNS 48 The Blood-Brain Barrier 53 Response of Axons to Destructive Lesions or Irritative Lesions 53 Clinical Problems 55 Matching Problems 58 Answers 59 3. Spinal Cord . 61 Organization and Roots 61 Motor Neural Systems 66 Reflexes 69 Sensory Systems 77 Dorsal Column/Medial Lemniscal System 77 iii N iv Contents Anterolateral System 80 Brown-Séquard Syndrome 85 Clinical Problems 89 Matching Problems 94 Answers 96 4. Brainstem . 99 Midbrain, Pons, and Medulla and their Cranial Nerves 99 Components of Motor and Sensory Systems in the Brainstem 105 Reticular Formation 110 Motor Nuclei of Cranial Nerves 110 Sensory Nuclei of Cranial Nerves 117 Cochlear Nerve and the Central Auditory System 120 Vestibular Nerve and the Vestibulo-Ocular Reflex 123 Arterial Blood Supply to the Brainstem 127 Brainstem Syndromes 128 Clinical Problems 131 Matching Problems 135 Answers 138 5. Cerebellum and Basal Ganglia . 141 Functional Comparison 141 Organization of the Cerebellum 142 Cerebellar Inputs 144 Cerebellar Outputs 145 Cerebellar Lesions 145 Organization of the Basal Ganglia 148 The Basal Ganglia Motor Pathways 148 The Other Basal Ganglia Pathways 152 Clinical Problems 154 Matching Problems 155 Answers 156 6. Diencephalon and Limbic System . 158 Thalamus 158 Hypothalamus 162 Epithalamus 167 Limbic System 168 Olfactory System 168 Hippocampus and Alzheimer’s Dementia 168 Amygdala and Klüver-Bucy Syndrome 172 Clinical Problems 173 N Contents v Matching Problems 174 Answers 175 7. Visual System, Pupillary Reflexes, and Conjugate Eye Movements . 177 The Eyeball 177 Retina 180 Visual Processing and Deficits 182 Ocular Reflexes 185 Lateral Geniculate Nucleus 187 Primary Visual or Calcarine Cortex 188 Conjugate Eye Movements 190 Clinical Problems 194 Matching Problems 197 Answers 199 8. Cerebral Cortex and Higher Functions . 201 Organization 201 Sensory Areas of Cerebral Cortex 203 Hemispheric Dominance, Handedness, and Language 203 Functional Features of the Frontal, Parietal, Temporal, and Occipital Lobes 204 The Internal Capsule 214 Electroencephalogram 215 The Ascending Arousal System 216 Sleep 217 Seizures 219 Arterial Blood Supply of the Cerebral Cortex 220 Clinical Problems 222 Matching Problems 224 Answers 225 Index . 227 This page intentionally left blank USING THE USMLE ROAD MAP SERIES FOR SUCCESSFUL REVIEW What Is the Road Map Series? Short of having your own personal tutor, the USMLE Road Map Series is the best source for efficient review of major concepts and information in the medical sciences. Why Do You Need A Road Map? It allows you to navigate quickly and easily through your physiology course notes and textbook and prepares you for USMLE and course examinations. How Does the Road Map Series Work? Outline Form: Connects the facts in a conceptual framework so that you understand the ideas and retain the information. Color and Boldface: Highlights words and phrases that trigger quick retrieval of concepts and facts. Clear Explanations: Are fine-tuned by years of student interaction. The material is written by authors selected for their excellence in teaching and their experience in preparing students for board examinations. Illustrations: Provide the vivid impressions that facilitate comprehension and recall. CLINICAL CORRELATION Clinical Correlations: Link all topics to their clinical applications, promoting fuller understanding and memory retention. Clinical Problems: Give you valuable practice for the clinical vignette-based USMLE questions. Matching Problems: Offer quick self-test of basic and clinical facts. Explanations of Answers: Are learning tools that allow you to pinpoint your strengths and weaknesses. vii Copyright © 2008 by The McGraw-Hill Companies, Inc. Click here for terms of use. This page intentionally left blank To my parents, Maggie and Barclay White; my wife, Kim; and my daughters, Kate and Kristen, all of whom make whatever I do worthwhile. ACKNOWLEDGMENTS I am indebted to Anne Marie Santilli, class of 2010, School of Osteopathic Medicine, UMDNJ, and to J. Douglas Jaffe, D.O., R.N. for their editorial efforts. Special thanks to Chris and Karen Zipp for their con- tributions to the second edition, and to Hazel Murphy for permission to use images of myelin-stained slides from the Drexel College of Medicine collection. ix Copyright © 2008 by The McGraw-Hill Companies, Inc. Click here for terms of use. This page intentionally left blank CHAPTERCHAPTER 11 DEVELOPMENT, GROSS N ANATOMY, AND BLOOD SUPPLY OF THE NERVOUS SYSTEM I. The nervous system consists of the central nervous system (CNS) and the peripheral nervous system (PNS). A. The CNS includes the brain in the cranial cavity and the spinal cord in the vertebral canal (Figure 1–1). 1. The CNS is organized into regions of gray matter and white matter. 2. Gray matter contains the cell bodies of neurons, their dendrites, and the proximal parts of their axons. 3. Groups of anatomically or functionally similar neuron cell bodies in the gray matter may be found in a nucleus, a lamina, or a layer. 4. White matter contains axons of neurons. Groups of anatomically or func- tionally similar axons may be found in a peduncle, a funiculus, a fasciculus, a lemniscus, or a tract. 5. Both gray and white matter also contain different types of glial or supporting cells. B. The PNS is composed of spinal nerves, cranial nerves, and autonomic nerves.