The Schwann cell: Morphology and development

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1 University Press Scholarship Online You are looking at 1-10 of 30 items for: keywords : nerve cell The Schwann cell: Morphology and development NAOMI KLEITMAN and RICHARD P. BUNGE in The Axon: Structure, Function and Pathophysiology Published in print: 1995 Published Online: May 2009 ISBN: eisbn: acprof:oso/ This chapter describes the sequential phenomena observed during the development of the peripheral nerve, with emphasis on the Schwann cell. It presents research elucidating the mechanisms by which these phenomena are controlled. The use of tissue culture models of nerve development is emphasized inasmuch as these have contributed greatly to the understanding of the role of each of the peripheral nerve cell types at each stage of differentiation. The chapter reviews how these studies have elucidated the interactions that create the fully functional nerve. Finally, it discusses ways in which understanding these cellular interactions may be exploited to maximize regeneration in the wake of injury. A Sketch History of the Microscopic Anatomy of the Nervous System Javier Defelipe in Cajal's Butterflies of the Soul: Science and Art January 2010 ISBN: eisbn: acprof:oso/ This chapter traces the history of various theories on the microscopic anatomy of the nervous system, with corresponding illustrations by the scientists themselves. The chapter is divided into three, covering the Benedictine period, the Black period, and the Colorful period. Page 1 of 6

2 Signaling Molecules: The First Growth Factor acprof:oso/ This chapter details early studies on the development of nerve cells. The nervous system arises from a single fertilized egg. Classical histologists visualized this process through the cells of the changing embryo. The first great synthesis was the idea of an organizer that directed the formation of the organs. The crux for the nervous system was how connections are established between cells, which implied the presence of intercellular signals. The clearest evidence for such a signal, called nerve growth factor, was reported in Subsequent experiments identified its molecular structure, which came to be known as NGF, the first of a growing number of neurotrophic and neurotrophic factors involved in neural development and in the plasticity of connections that underlie learning, memory, and response to injury. Cell Biology and the Synapse acprof:oso/ Before the 1950s, cell structure could be studied only under the light microscope, and the organelles that do the work of the cell were seen only indistinctly. By the end of the 1950s, the electron microscope (EM) and other methods had opened up an entirely new field of cell biology, in which each organelle was recognized as contributing its particular set of functions to the overall mechanism of the cell. Most importantly for the nervous system, the synaptic contacts made by nerve cells could be clearly identified and characterized. Many neurological disorders are due to pathological changes affecting synaptic function, and much of pharmaceutical research on drug discovery is aimed at the synapse. This chapter focuses on the chemical synapse as the organelle most special for nerve cells. Page 2 of 6

3 Physiology: Synaptic Potentials and Receptor Potentials acprof:oso/ This chapter details early studies on synaptic and reception potentials. After excitability, the second key property of nerve cells is the action that occurs at the synapses between cells. This is the crucial property that underlies the coordinated activity of neuronal populations. In analogy with the action potentials of the nerve fibers, the actions at synapses are called synaptic potentials. The era of investigation of synaptic potentials was opened by the development of fine-tipped micropipettes that could record the membrane currents and potentials near the sites of synapses. A leading model for these mechanisms was the nerve-muscle junction, where Bernard Katz and colleagues showed that the invading action potential in the nerve activated an end-plate potential, shown to be due to the summed action of many miniature responses to transmitter quanta presumably corresponding to the release of vesicles from the presynaptic terminal. Beginnings: Cajal and the Neuron Theory ( ) Joseph D. Robinson in Mechanisms of Synaptic Transmission: Bridging the Gaps ( ) Published in print: 2001 Published Online: March 2012 ISBN: eisbn: acprof:oso/ This chapter describes selected developments between the meeting of the German Anatomical Society in Berlin in 1889 and the publication twenty years later of Santiago Ramón y Cajal's treatise on the regeneration in the nervous system. Cajal formulated one of the early arguments for the Neuron Theory from studying the embryological development of nerve cells, particularly the sequential growth of their processes. In the two decades following Cajal's mission to Berlin, a flourishing research program was established, rooted in the neuron, the fundamental morphological and functional unit of the nervous system. Page 3 of 6

4 The Synapse: Function, Plasticity, and Neurotrophism Motoy Kuno Published in print: 1994 Published Online: March 2012 ISBN: eisbn: Item type: book acprof:oso/ The synapse not only provides a bridge from one nerve cell to the next; its function can be modified by experience, making it important for learning and memory. This overview of the synapse provides a review of current concepts in neurobiology, with specific reference to synaptic plasticity, neurotransmission, and neurotrophism. These areas have been advanced dramatically by the application of molecular biology techniques, and this book provides a synthesis of these advances. The book incorporates all the latest thinking and current research together with a brief historical overview of research in the field. Signaling Molecules: The First Neurotransmitters in the Brain acprof:oso/ This chapter details early studies on signal molecules between nerve cells that mediate behavior. The key signal molecules for these functions are neurotransmitters, neuropeptides, internal second messengers, hormones, and pheromones. Apart from the sex hormones, most of these major types of components were first identified and their significance recognized in and around the 1950s. Before the 1950s, the biochemistry and pharmacology of the brain were essentially nonexistent. By the end of the decade, all the major categories of signaling agents had begun to emerge and the first textbook of brain biochemistry had appeared. Second messengers were discovered in 1957 and have been an essential motif in neurobiology since the 1970s. Neuropeptides were also first discovered in the 1950s and became a major theme in the 1970s, linked to second messengers. Pheromones were identified and named in the 1950s, and are recognized to control the social behaviors of most animals, including significant roles in humans. Page 4 of 6

5 Neurons and Muscles: The Sources of Psychophysiological Recordings Robert M. Stern, William J. Ray, and Karen S. Quigley in Psychophysiological Recording Published in print: 2000 Published Online: March 2012 ISBN: eisbn: Page 5 of 6 acprof:oso/ Psychophysiology focuses on the study of bodily responses that originate as electrochemical changes in neurons (nerve cells), muscles, and gland cells. These signals spread from their sources through the body to the skin surface, appearing to a recording electrode on the body surface in a somewhat altered form. Understanding the genesis of bioelectric potentials will help in interpreting the surface potentials and serve as a reminder that whatever their relation to behavior, psychophysiological responses reflect the functioning of neurons, muscles, and glands. The nervous system controls the bodily functions measured by psychophysiologists, including muscle action, organ function, and glandular activity. For example, the coordinated contraction of thousands of skeletal muscle cells moves us through our environment, enables us to react to its changes, and is the mechanism of singing, smiling, sitting, and eating. This chapter discusses the organization of the nervous system, the function of nerve and muscle cells, and the sources of the bioelectric potentials that can be recorded from the surface of the skin. As the Worm Turns: Learning and Memory in the Roundworm C. elegans William R. Clark and Michael Grunstein in Are We Hardwired?: The Role of Genes in Human Behavior Published in print: 2004 Published Online: April 2010 ISBN: eisbn: acprof:oso/ One of the most important behaviors with integrated neurological circuits is learning, which is based on the development of memory. True learning and memory are found only in multicellular animals. But it is amazing how few cells can regulate highly complex behavioral activity. The roundworm C. elegans has only 302 nerve cells, but this handful of cells carry out the main neurological functions found in humans: afferent detection of environmental signals, selection of an efferent motor response, and integration of these two pathways. Moreover, these worms

6 use neurotransmitters functionally similar to those in humans, and can be shown to have true memory. The small size of C. elegans, and its limited number of genes (c.13,000), has made possible the dissection of the cellular and molecular basis underlying learning and memory in these organisms. This in turn has provided valuable direction to similar studies in higher animals. Page 6 of 6

Origin of Electrical Membrane Potential

Origin of Electrical Membrane Potential parti This book is about the physiological characteristics of nerve and muscle cells. As we shall see, the ability of these cells to generate and conduct electricity