The enteric nervous system (ENS) is a complex neural network embedded in the gut wall that orchestrates the reflex behaviors of the intestine. The ENS is often referred to as the “little brain” in the gut because the ENS is more similar in size, complexity and autonomy to the central nervous system (CNS) than other components of the autonomic nervous system. Like the brain, the ENS is composed of neurons that are surrounded by glial cells. Enteric glia are a unique type of peripheral glia that are similar to astrocytes of the CNS. Yet enteric glial cells also differ from astrocytes in many important ways. The roles of enteric glial cell populations in the gut are beginning to come to light and recent evidence implicates enteric glia in almost every aspect of gastrointestinal physiology and pathophysiology. However, elucidating the exact mechanisms by which enteric glia influence gastrointestinal physiology and identifying how those roles are altered during gastrointestinal pathophysiology remain areas of intense research. The purpose of this e-book is to provide an introduction to enteric glial cells and to act as a resource for ongoing studies on this fascinating population of glia. Table of Contents: Introduction / A Historical Perspective on Enteric Glia / Enteric Glia: The Astroglia of the Gut / Molecular Composition of Enteric Glia / Development of Enteric Glia / Functional Roles of Enteric Glia / Enteric Glia and Disease Processes in the Gut / Concluding Remarks / References / Author Biography

Glial Physiology and Pathophysiology provides a comprehensive, advanced text on the biology and pathology of glial cells. Coverae includes: the morphology and interrelationships between glial cells and neurones in different parts of the nervous systems the cellular physiology of the different kinds of glial cells the mechanisms of intra- and inter-cellular signalling in glial networks the mechanisms of glial-neuronal communications the role of glial cells in synaptic plasticity, neuronal survival and development of nervous system the cellular and molecular mechanisms of metabolic neuronal-glial interactions the role of glia in nervous system pathology, including pathology of glial cells and associated diseases - for example, multiple sclerosis, Alzheimer's, Alexander disease and Parkinson's Neuroglia oversee the birth and development of neurones, the establishment of interneuronal connections (the 'connectome'), the maintenance and removal of these inter-neuronal connections, writing of the nervous system components, adult neurogenesis, the energetics of nervous tissue, metabolism of neurotransmitters, regulation of ion composition of the interstitial space and many, many more homeostatic functions. This book primes the reader towards the notion that nervous tissue is not divided into more important and less important cells. The nervous tissue functions because of the coherent and concerted action of many different cell types, each contributing to an ultimate output. This reaches its zenith in humans, with the creation of thoughts, underlying acquisition of knowledge, its analysis and synthesis, and contemplating the Universe and our place in it. An up-to-date and fully referenced text on the most numerous cells in the human brain Detailed coverage of the morphology and interrelationships between glial cells and neurones in different parts of the nervous system Describes the role og glial cells in neuropathology Focus boxes highlight key points and summarise important facts Companion website with downloadable figures and slides

The enteric nervous system (ENS), also known as second brain, innervates our gastrointestinal tract controlling its functions, such as motility, fluid secretion, nutrient absorption, and even involvement in the control of immunity and inflammatory processes. In the gut, the gliocytes are known as enteric glial cells (EGCs). Enteric glial cells form a network that permeates the entire gut. Enteric glia express the cell surface hemichannel of connexin-43 (Cx43) necessary for the propagation of Ca2 + responses, necessary to maintain their functions. In this chapter, besides the development of ENS and its glial cells and the similarities with the astrocytes in the central nervous system, we approached the important role of the glial network in the control of gut homeostasis, in the interaction with the immune system, and its participation in pathological conditions. EGCs are even capable of replacing lost neurons. Thus the enteric glia is a multifunctional cell, which through its multiple interactions maintains the integrity of the ENS allowing it to be resistant to the different and constant aggressions suffered by the digestive system.

This book has been designed to help medical students succeed with their histology classes, while using less time on studying the curriculum. The book can both be used on its own or as a supplement to the classical full-curriculum textbooks normally used by the students for their histology classes. Covering the same curriculum as the classical textbooks, from basic tissue histology to the histology of specific organs, this book is formatted and organized in a much simpler and intuitive way. Almost all text is formatted in bullets or put into structured tables. This makes it quick and easy to digest, helping the student get a good overview of the curriculum. It is easy to locate specific information in the text, such as the size of cellular structures etc. Additionally, each chapter includes simplified illustrations of various histological features. The aim of the book is to be used to quickly brush up on the curriculum, e.g. before a class or an exam. Additionally, the book includes guides to distinguish between the different histological tissues and organs that can be presented to students microscopically, e.g. during a histology spot test. This guide lists the specific characteristics of the different histological specimens and also describes how to distinguish a specimen from other similar specimens. For each histological specimen, a simplified drawing and a photomicrograph of the specimen, is presented to help the student recognize the important characteristics in the microscope. Lastly, the book contains multiple “memo boxes” in which parts of the curriculum are presented as easy-to-remember mnemonics.

Enteric glial cell (EGC) markers were thoroughly characterized in the human enteric nervous system (ENS) and EGC numbers were compared in man and guinea pig. As a result, the Sox8/9/10 antibody was shown to be an excellent investigative tool to assess EGC in the ENS and the glia index was identified as the most robust quantitative descriptor within a species. Subsequently, this Sox8/9/10 was used in Crohnþs disease specimens to quantify enteric glia. In a parallel approach, interactions of EGC and the intestinal epithelial barrier were analyzed. Results from these experiments indicate a protective effect of EGCs on the intestinal epithelial barrier in intestinal inflammation. The observed expression of GDNF, NGF, NT-3 and their receptors by EGC points to promising targets for further research to elucidate the exact nature of glial-derived mucosa-protective factors.

The gastrointestinal tract is a long, muscular tube responsible for the digestion of food, assimilation of nutrients and elimination of waste. This is achieved by secretion of digestive enzymes and absorption from the intestinal lumen, with different regions playing specific roles in the processing of specific nutrients. These regions come into play sequentially as ingested material is moved along the length of the GI tract by contractions of the muscle layers. In some regions like the oesophagus transit it rapid and measured in seconds while in others like the colon transit is measured in hours and even days, commensurate with the relative slow fermentation that takes place in the large bowel. An hierarchy of controls, neural and endocrine, serve to regulate the various cellular targets that exist in the gut wall. These include muscle cells for contraction and epithelial cells for secretion and absorption. However, there are complex interactions between these digestive mechanisms and other mechanisms that regulate blood flow, immune function, endocrine secretion and food intake. These ensure a fine balance between the ostensibly conflicting tasks of digestion and absorption and protection from potentially harmful ingested materials. They match assimilation of nutrients with hunger and satiety and they ensure that regions of the GI tract that are meters apart work together in a coordinated fashion to match these diverse functions to the digestive needs of the individual. This ebook will provide an overview of the neural mechanisms that control gastrointestinal function. Table of Contents: Neural Control of Gastrointestinal Function / Cells and Tissues / Enteric Nervous System / From Gut to CNS: Extrinsic Sensory Innervation / Sympathetic Innervation of the Gut / Parasympathetic Innervation of the Gut / Integration of Function / References

Easily understood, up-to-date and clinically relevant, this book provides junior anaesthetists with an essential physiology resource.

Deglutition or a swallow begins as a voluntary act in the oral cavity but proceeds autonomously in the pharynx and esophagus. Bilateral sequenced activation and inhibition of more than 25 pairs of muscles of mouth, pharynx, larynx, and esophagus is required during a swallow. A single swallow elicits peristalsis in the pharynx and esophagus along with relaxation of upper and lower esophageal sphincters. Multiple swallows, at closely spaced time intervals, demonstrate deglutitive inhibition; sphincters remain relaxed during the entire period, but only the last swallow elicits peristalsis. Laryngeal inlet closure or airway protection is very important during swallow. Upper part of the esophagus that includes upper esophageal sphincter is composed of skeletal muscles, middle esophagus is composed of a mixture of skeletal and smooth muscles, and lower esophagus, including lower esophageal sphincter, is composed of smooth muscles. Peristalsis progresses in seamless fashion, despite separate control mechanism, from the skeletal to smooth muscle esophagus. The esophagus's circular and longitudinal muscle layers contract synchronously during peristalsis. Sphincters maintain continuous tone; neuromuscular mechanisms for tonic closure in the upper and lower esophageal sphincters are different. Lower esophageal sphincter transient relaxation, belching mechanism, regurgitation, vomiting, and reflux are mediated via the brain stem. Table of Contents: Introduction / Central Program Generator and Brain Stem / Pharynx-Anatomy, Neural Innervation, and Motor Pattern / Upper Esophageal Sphincter / Neuromuscular Anatomy of Esophagus and Lower Esophageal Sphincter / Extrinsic Innervation: Parasympathetic and Sympathetic / Interstitial Cells of Cajal / Recording Techniques / Motor Patterns of the Esophagus-Aboral and Oral Transport / Deglutitive Inhibition and Muscle Refractoriness / Peristalsis in the Circular and Longitudinal Muscles of the Esophagus / Neural and Myogenic Mechanism of Peristalsis / Central Mechanism of Peristalsis-Cortical and Brain Stem Control / Peripheral Mechanisms of Peristalsis / Central Versus Peripheral Mechanism of Deglutitive Inhibition / Neural Control of Longitudinal Muscle Contraction / Modulation of Primary and Secondary Peristalsis / Neural Control of Lower Esophageal Sphincter and Crural Diaphragm / Lower Esophageal Sphincter / Swallow-Induced LES Relaxation / Crural Diaphragm Contribution to EGJ and Neural Control / Transient LES Relaxation and Pharmacological Inhibition / Compliance of the EGJ / References