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Enteric Nervous System: Two ganglionated neural plexuses in the gut wall which form one of the three major divisions of the autonomic nervous system. The enteric nervous system innervates the gastrointestinal tract, the pancreas, and the gallbladder. It contains sensory neurons, interneurons, and motor neurons. Thus the circuitry can autonomously sense the tension and the chemical environment in the gut and regulate blood vessel tone, motility, secretions, and fluid transport. The system is itself governed by the central nervous system and receives both parasympathetic and sympathetic innervation. (From Kandel, Schwartz, and Jessel, Principles of Neural Science, 3d ed, p766)

Isolation of Enteric Glial Cells from the Submucosa and Lamina Propria of the Adult Mouse

1Department of Internal Medicine-Gastroenterology, University of Michigan, 2Department of Molecular and Integrative Physiology, University of Michigan, 3Department of Molecular, Cellular and Developmental Biology, University of Michigan, 4Department of Gastrointestinal Surgery, The First Affiliated Hospital of Guangxi Medical University, 5Division of Gastroenterology, University of Arizona College of Medicine

JoVE 57629

 Biology

Neural Regulation

JoVE 10835

Digestion begins with a cephalic phase that prepares the digestive system to receive food. When our brain processes visual or olfactory information about food, it triggers impulses in the cranial nerves innervating the salivary glands and stomach to prepare for food.

The cephalic phase is a conditioned or learned response to familiar foods. Our appetite or desire for a particular food modifies the preparatory responses directed by the brain. Individuals may produce more saliva and stomach rumblings in anticipation of apple pie than of broccoli. Appetite and desire are products of the hypothalamus and amygdala—brain areas associated with visceral processes and emotion. After the cephalic phase, digestion is governed by the enteric nervous system (ENS) as an unconditioned reflex. Individuals do not have to learn how to digest food; it happens regardless of whether it is apple pie or broccoli. The ENS is unique in that it functions (mostly) independent of the brain. About 90% of the communication are messages sent from the ENS to the brain rather than the other way around. These messages give the brain information about satiety, nausea, or bloating. The ENS, as part of the peripheral nervous system, is also unique in that it contains both motor and sensory neurons. For example, the ENS directs smooth muscle movements that churn and propel food al

 Core: Nutrition and Digestion

Hormonal Regulation

JoVE 10836

Hormones regulate a significant portion of digestion through activation of the neuroendocrine system. The neuroendocrine system of digestion contains many different hormones all with multiple functions that are both, directly and indirectly, involved in digestion.

Starting in the stomach, when proteins are detected by sensory neurons of the enteric nervous system, the pyloric gland is stimulated to release gastrin. In turn, this hormone induces the release of histamine. Combined, they initiate the production of hydrochloric acid which facilitates digestion—turning food into chyme. When the pH of the stomach becomes more acidic, a negative feedback loop halts the production of both hormones. The chyme then moves to the duodenum, where several hormones are released—each with multiple functions. Some inhibit digestion in the stomach. Gastric inhibitory peptide (GIP) slows stomach churning. Secretin inhibits gastric juice production and, along with cholecystokinin (CCK), induces the pyloric sphincter between the stomach and duodenum to close. This limits the volume of chyme in the duodenum, pacing the rate of digestion. Once the chyme is in the duodenum, secretin prompts the release of bicarbonate from the pancreas. This reduces the acidity of the chyme, protecting the sensitive lining of the duodenum and setting up an optimal environment

 Core: Nutrition and Digestion

Pleiotropy

JoVE 10780

Pleiotropy is the phenomenon in which a single gene impacts multiple, seemingly unrelated phenotypic traits. For example, defects in the SOX10 gene cause Waardenburg Syndrome Type 4, or WS4, which can cause defects in pigmentation, hearing impairments, and an absence of intestinal contractions necessary for elimination. This diversity of phenotypes results from the expression pattern of SOX10 in early embryonic and fetal development. SOX10 is found in neural crest cells that form melanocytes, which are involved in pigmentation and also in the early development of the ear. SOX10 is also expressed in nerve tissue that eventually contributes to the enteric nervous system in the gut, which controls the contractions necessary for waste elimination. In this way, SOX10 exhibits pleiotropic effects, because it influences multiple phenotypes. Pleiotropy can arise through several mechanisms. Gene pleiotropy occurs when a gene has various functions due to encoding a product that interacts with multiple proteins or catalyzes multiple reactions. For example, in humans, an abnormal copy of the SOX10 gene, in which a region is deleted, can lead to developmental defects that include a white forelock, different-colored irises (e.g., one blue and one brown), and regions of unpigmented skin. These traits are all symptoms of a di

 Core: Classical and Modern Genetics

Dissection, Culture and Analysis of Primary Cranial Neural Crest Cells from Mouse for the Study of Neural Crest Cell Delamination and Migration

1Centre for Craniofacial and Regenerative Biology, King's College London, 2Institute of Molecular Biology and Biotechnology, FORTH, Department of Biomedical Research, University of Ioannina, 3Randall Centre of Cell & Molecular Biophysics, King's College London, 4Department of Biological Applications and Technology, University of Ioannina

JoVE 60051

 Developmental Biology

Assessing Cellular Stress and Inflammation in Discrete Oxytocin-secreting Brain Nuclei in the Neonatal Rat Before and After First Colostrum Feeding

1Department of Psychiatry, Columbia University, 2Department of Pathology & Cell Biology, Columbia University Medical Center, 3Department of Psychiatry, Division of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, 4EB Sciences

JoVE 58341

 Immunology and Infection

Dual Labeling of Neural Crest Cells and Blood Vessels Within Chicken Embryos Using ChickGFP Neural Tube Grafting and Carbocyanine Dye DiI Injection

1Birth Defects Research Centre, UCL Institute of Child Health, 2Blizard Institute, Centre for Digestive Diseases, Queen Mary University of London, Barts and The London School of Medicine and Dentistry, 3Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam

JoVE 52514

 Developmental Biology
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