DOCSLIB.ORG

Digestive System Digestive System

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Digestive System Digestive System DIGESTIVE SYSTEM DIGESTIVE SYSTEM • To achieve the goal of providing energy and nutrients to the body. • Six major functions take place in the digestive system: • Ingestion. • Secretion. • Mixing and movement. • Digestion. • Absorption. • Excretion. Introduction to Digestive system • ESOPHAGUS • STOMACH • DUODENUM Function of the organ Organ Major function Mouth Ingests food Chews and mixes food Begins chemical breakdown of carbohydrates Moves food into the pharynx Begins breakdown of lipids via lingual lipase Function of the organ Organ Major function Stomach Mixes and churns food with gastric juices to form chyme Begins chemical breakdown of proteins Releases food into the duodenum as chyme Absorbs some fat-soluble substances (for example, alcohol, aspirin) Function of the organ Organ Major function Mixes chyme with digestive juices Propels food at a rate slow enough for digestion and absorption Absorbs breakdown products of carbohydrates, proteins, lipids, and nucleic acids, along with vitamins, Small intestine minerals, and water Performs physical digestion via segmentation the small intestine is about 6 meters or 20 feet long . Function of the organ Organ Major function Accessory organs Liver: produces bile salts, which emulsify lipids, aiding their digestion and absorption Gallbladder: stores, concentrates, and releases bile Pancreas: produces digestive enzymes and bicarbonate Function of the organ Organ Major function Large intestine Further breaks down food residues Absorbs most residual water, electrolytes, and vitamins produced by enteric bacteria Propels feces toward rectum Eliminates feces the large intestine is about 1.5 meters or 5 feet long Sigmoid colon • Sigmoid colon, a terminal section of the large intestine that connects the descending colon to the rectum; its function is to store fecal wastes until they are ready to leave the body. The sigmoid colon derives its name from the fact that it is curved in the form of an S rectum • The rectum is the last stop before the feces is eliminated through the anal canal. Similar to the colon electrolytes are absorbed (sodium, potassium, chloride) and indigestible food ingredients are decomposed by anaerobic bacteria. The stool is thickened through water absorption and mixed with mucus Control of digestive systems • The enteric nervous system (ENS), which is embedded in the lining of the gastrointestinal system, can operate independently of the brain and the spinal cord. • The ENS consists of two plexuses, the submucosal and the myenteric. The myenteric plexus increases the tone of the gut and the velocity and intensity of contractions. The submucosal plexus is involved with local conditions and controls local secretion, absorption, and muscle movements. • While described as a second brain, the enteric nervous system normally communicates with the central nervous system (CNS) through the parasympathetic (via the vagus nerve ) and sympathetic (via the prevertebral ganglia) nervous systems, but can still function when the vagus nerve is severed. • The ENS includes efferent neurons, afferent neurons, and interneurons, all of which make the ENS capable of carrying reflexes and acting as an integrating center in the absence of CNS input. • The ENS contains support cells, which are similar to the astroglia of the brain, and a diffusion barrier around the capillaries surrounding the ganglia, which is similar to the blood –brain barrier of cerebral blood vessels. Yogic application • अहं वैश्वानरो भूत्वा प्रनननाम देह माश्रीताम प्राणापान सामायुक्तम पाचामान्याम चातुनविधाम | • वैश्वानर- जठार अनि , • importance in ayurveda- root of all disease • Yogic five prana concepet • Aim of yoga is balancing of all five prana and upaprana Improve digestive system • Effect of Backbending, twisting asana, forward bend • Effect of shudhi kriya ( kapalbhati , nauli ) , pranayam • Effect of meditation .
Load more

Recommended publications
  • The Baseline Structure of the Enteric Nervous System and Its Role in Parkinson’S Disease
    life Review The Baseline Structure of the Enteric Nervous System and Its Role in Parkinson’s Disease Gianfranco Natale 1,2,* , Larisa Ryskalin 1 , Gabriele Morucci 1 , Gloria Lazzeri 1, Alessandro Frati 3,4 and Francesco Fornai 1,4 1 Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy; [email protected] (L.R.); [email protected] (G.M.); [email protected] (G.L.); [email protected] (F.F.) 2 Museum of Human Anatomy “Filippo Civinini”, University of Pisa, 56126 Pisa, Italy 3 Neurosurgery Division, Human Neurosciences Department, Sapienza University of Rome, 00135 Rome, Italy; [email protected] 4 Istituto di Ricovero e Cura a Carattere Scientifico (I.R.C.C.S.) Neuromed, 86077 Pozzilli, Italy * Correspondence: [email protected] Abstract: The gastrointestinal (GI) tract is provided with a peculiar nervous network, known as the enteric nervous system (ENS), which is dedicated to the fine control of digestive functions. This forms a complex network, which includes several types of neurons, as well as glial cells. Despite extensive studies, a comprehensive classification of these neurons is still lacking. The complexity of ENS is magnified by a multiple control of the central nervous system, and bidirectional communication between various central nervous areas and the gut occurs. This lends substance to the complexity of the microbiota–gut–brain axis, which represents the network governing homeostasis through nervous, endocrine, immune, and metabolic pathways. The present manuscript is dedicated to Citation: Natale, G.; Ryskalin, L.; identifying various neuronal cytotypes belonging to ENS in baseline conditions.
    [Show full text]
  • Secretin-Induced Gastric Relaxation Is Mediated by Vasoactive Intestinal Polypeptide and Prostaglandin Pathways
    Neurogastroenterol Motil (2009) 21, 754–e47 doi: 10.1111/j.1365-2982.2009.01271.x Secretin-induced gastric relaxation is mediated by vasoactive intestinal polypeptide and prostaglandin pathways Y. LU & C. OWYANG Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA Abstract Secretin has been shown to delay gastric vagally mediated pathway. Through nicotinic emptying and inhibit gastric motility. We have dem- synapses, secretin stimulates VIP release from post- onstrated that secretin acts on the afferent vagal ganglionic neurons in the gastric myenteric plexus, pathway to induce gastric relaxation in the rat. How- which in turn induces gastric relaxation through a ever, the efferent pathway that mediates the action of prostaglandin-dependent pathway. secretin on gastric motility remains unknown. We Keywords gastric relaxation, indomethacin, vagus recorded the response of intragastric pressure to graded nerve. doses of secretin administered intravenously to anaesthetized rats using a balloon attached to a cath- eter and placed in the body of the stomach. Secretin INTRODUCTION evoked a dose-dependent decrease in intragastric Secretin has been shown to inhibit gastric contrac- pressure. The threshold dose of secretin was 1.4 pmol tions and delay gastric emptying of liquids and kg)1 h)1 and the effective dose, 50% was 5.6 pmol kg)1 solids.1–3 However, the mechanisms of secretinÕs h)1. Pretreatment with hexamethonium markedly inhibitory effects on gastric motility remain unclear. reduced gastric relaxation induced by secretin The gene expression of secretin receptor has been (5.6 pmol kg)1 h)1). Bilateral vagotomy also signifi- demonstrated in the rat nodose ganglia.4 We have cantly reduced gastric motor responses to secretin.
    [Show full text]
  • Enteric Nervous System (ENS): 1) Myenteric (Auerbach) Plexus & 2
    Enteric Nervous System (ENS): 1) Myenteric (Auerbach) plexus & 2) Submucosal (Meissner’s) plexus à both triggered by sensory neurons with chemo- and mechanoreceptors in the mucosal epithelium; effector motors neurons of the myenteric plexus control contraction/motility of the GI tract, and effector motor neurons of the submucosal plexus control secretion of GI mucosa & organs. Although ENS neurons can function independently, they are subject to regulation by ANS. Autonomic Nervous System (ANS): 1) parasympathetic (rest & digest) – can innervate the GI tract and form connections with ENS neurons that promote motility and secretion, enhancing/speeding up the process of digestion 2) sympathetic (fight or flight) – can innervate the GI tract and inhibit motility & secretion by inhibiting neurons of the ENS Sections and dimensions of the GI tract (alimentary canal): Esophagus à ~ 10 inches Stomach à ~ 12 inches and holds ~ 1-2 L (full) up to ~ 3-4 L (distended) Duodenum à first 10 inches of the small intestine Jejunum à next 3 feet of small intestine (when smooth muscle tone is lost upon death, extends to 8 feet) Ileum à final 6 feet of small intestine (when smooth muscle tone is lost upon death, extends to 12 feet) Large intestine à 5 feet General Histology of the GI Tract: 4 layers – Mucosa, Submucosa, Muscularis Externa, and Serosa Mucosa à epithelium, lamina propria (areolar connective tissue), & muscularis mucosae Submucosa à areolar connective tissue Muscularis externa à skeletal muscle (in select parts of the tract); smooth muscle (at least 2 layers – inner layer of circular muscle and outer layer of longitudinal muscle; stomach has a third layer of oblique muscle under the circular layer) Serosa à superficial layer made of areolar connective tissue and simple squamous epithelium (a.k.a.
    [Show full text]
  • Download PDF Enteric Nervous System Development in Cavitary
    Romanian Journal of Morphology and Embryology 2008, 49(1):63–67 ORIGINAL PAPER Enteric nervous system development in cavitary viscera allocated to the celiac plexus ALINA MARIA ŞIŞU1), CODRUŢA ILEANA PETRESCU1), C. C. CEBZAN1), M. C. NICULESCU1), V. NICULESCU1), P. L. MATUSZ1), M. C. RUSU2) 1)Department of Anatomy and Embryology, “Victor Babeş” University of Medicine and Pharmacy, Timisoara 2)Department of Anatomy and Embryology, Faculty of Dental Medicine, “Carol Davila” University of Medicine and Pharmacy, Bucharest Abstract Enteric nervous system (ENS) is a network made of neuronal cells and nervous fibers. There are two plexuses: myenteric of Auerbach and sub mucous of Meissner and Henle. Many substances are involved in neurotransmission at ENS level. ENS assures all gastrointestinal system functions: digestion, absorption, etc. Our study is made on 23 human fetal specimens at different ages of evolution with crown-rump lengths from 9 to 28 cm, and three new born human specimens. We used the Trichrome Masson stain technique and the argental impregnation Bielschowsky on block technique for microscopic evidence. Our study concerned the cavitary viscera allocated to the celiac plexus, involving all layers of each studied viscera. Keywords: viscera, neurons, celiac plexus, argental impregnation. Introduction Auerbach myenteric plexus, with location between the longitudinal and circular muscular layers and sub The enteric nervous system (ENS) is from mucous plexus (Meissner and Henle) between the morphological and neurochemistry point of view a real circular muscle and mucous muscle layer. “brain”. At a complex network level made from neurons The ultra structural studies show that the ENS and nervous fibers we find much more structure is closer to the central nervous system than the neurotransmitters and neuromodulaters than anywhere sympathetic and parasympathetic ganglia [5–7].
    [Show full text]
  • 1 the Anatomy and Physiology of the Oesophagus
    111 2 3 1 4 5 6 The Anatomy and Physiology of 7 8 the Oesophagus 9 1011 Peter J. Lamb and S. Michael Griffin 1 2 3 4 5 6 7 8 911 2011 location deep within the thorax and abdomen, 1 Aims a close anatomical relationship to major struc- 2 tures throughout its course and a marginal 3 ● To develop an understanding of the blood supply, the surgical exposure, resection 4 surgical anatomy of the oesophagus. and reconstruction of the oesophagus are 5 ● To establish the normal physiology and complex. Despite advances in perioperative 6 control of swallowing. care, oesophagectomy is still associated with the 7 highest mortality of any routinely performed ● To determine the structure and function 8 elective surgical procedure [1]. of the antireflux barrier. 9 In order to understand the pathophysiol- 3011 ● To evaluate the effect of surgery on the ogy of oesophageal disease and the rationale 1 function of the oesophagus. for its medical and surgical management a 2 basic knowledge of oesophageal anatomy and 3 physiology is essential. The embryological 4 Introduction development of the oesophagus, its anatomical 5 structure and relationships, the physiology of 6 The oesophagus is a muscular tube connecting its major functions and the effect that surgery 7 the pharynx to the stomach and measuring has on them will all be considered in this 8 25–30 cm in the adult. Its primary function is as chapter. 9 a conduit for the passage of swallowed food and 4011 fluid, which it propels by antegrade peristaltic 1 contraction. It also serves to prevent the reflux Embryology 2 of gastric contents whilst allowing regurgita- 3 tion, vomiting and belching to take place.
    [Show full text]
  • NROSCI/BIOSC 1070 and MSNBIO 2070 November 15, 2017 Gastrointestinal 1 Functions of the Digestive Tract
    NROSCI/BIOSC 1070 and MSNBIO 2070 November 15, 2017 Gastrointestinal 1 Functions of the Digestive Tract. The digestive system has two primary roles: digestion, or the chemical and mechanical breakdown of foods into small molecules that can absorbed, or moved across the intestinal mucosa into the bloodstream. In order to accomplish these functions, the secretion of enzymes, hormones, mucus, and paracrines by the gastrointestinal organs is needed. Furthermore, motility, or controlled movement of materials through the digestive tract is required. In addition to these primary functions, the gastrointestinal tract faces a number of challenges. Almost 7 liters of fluid must be released into the lumen of the digestive tract per day to allow for digestion and absorption to occur. Clearly, most of this fluid must be reabsorbed or dehydration will occur. Furthermore, the inner surface of the digestive tract is technically in contact with the external environment; for this reason, protective mechanisms are needed. In part, these mechanisms must protect against the secretions of the GI tract, including acid and enzymes. Anatomy of the Gastrointestinal System November 15, 2017 Page 1 GI 1 The anatomy of the GI system is illustrated in the previous 2 figures. The organs involved in digestion and absorption include the salivary glands, esophagus, stomach, small intestine, liver, pancreas, and large intestine. In addition, 7 sphincters control the movement of material and secretions between the organs. The total length of the GI tract is about 15 feet, of which 13 feet are comprised of intestine. The processed material within the GI tract is referred to as chyme.
    [Show full text]
  • Interactions of the Enteric Nervous System with the Gut Microbiome in the Neuroligin-3 R451C Mouse Model of Autism
    Interactions of the enteric nervous system with the gut microbiome in the neuroligin-3R451C mouse model of autism M.H.M. Madusani Herath Submitted in total fulfilment of the requirements of the degree of Doctor of Philosophy September 2020 Department of Physiology The University of Melbourne ABSTRACT Autism patients are four times more likely to be hospitalized due to gastrointestinal (GI) dysfunction compared to the general public. However, the exact cause of GI dysfunction in individuals with autism is currently unknown. Genetic predisposition to autism spectrum disorder (ASD) has been highlighted in various studies and mutations in genes that affect nervous system function can drive both behavioural abnormalities and GI dysfunction in autism. Neuroligin-3 (NLGN3) is a postsynaptic membrane protein and the R451C missense mutation in the NLGN3 gene is associated with ASD. Recent studies revealed that the NLGN3 R451C mutation induces GI dysfunction in autism patients as well as in mice but, the cellular localization and the effects of this mutation on NLGN3 production in the enteric nervous system (ENS) have not been reported to date. The intestinal mucosal barrier is the interface separating the external environment from the interior of the body. Mucosal barrier functions are directly regulated by the enteric nervous system. Therefore, ENS dysfunction can induce mucosal barrier impairments. An impaired intestinal barrier has been reported in autism patients, but neurally-mediated barrier dysfunctions have not been assessed in transgenic autism mouse models with an altered nervous system. The intestinal mucus layer is the outermost layer of the mucosa which separates the intestinal microbiota from the intestinal epithelium.
    [Show full text]
  • Activation of Intrinsic Afferent Pathways in Submucosal Ganglia of the Guinea Pig Small Intestine
    The Journal of Neuroscience, May 1, 2000, 20(9):3295–3309 Activation of Intrinsic Afferent Pathways in Submucosal Ganglia of the Guinea Pig Small Intestine Hui Pan and Michael D. Gershon Department of Anatomy and Cell Biology, Columbia University College of Physicians and Surgeons, New York, New York 10032 The enteric nervous system contains intrinsic primary afferent blocked by an antagonist of human calcitonin gene-related neurons that allow mucosal stimulation to initiate reflexes with- peptide (hCGRP8–37). hCGRP8–37 also inhibited the spread of out CNS input. We tested the hypothesis that submucosal excitation in the submucosal plexus, assessed by measuring primary afferent neurons are activated by 5-hydroxytryptamine the uptake of FM2-10 and induction of c-fos. In summary, data (5-HT) released from the stimulated mucosa. Fast and/or slow are consistent with the hypothesis that 5-HT from enterochro- EPSPs were recorded in submucosal neurons after the delivery maffin cells in response to mucosal stimuli initiates reflexes by of exogenous 5-HT, WAY100325 (a 5-HT1P agonist), mechani- stimulating 5-HT1P receptors on submucosal primary afferent cal, or electrical stimuli to the mucosa of myenteric plexus-free neurons. Second-order neurons respond to these cholinergic/ preparations (Ϯ extrinsic denervation). These events were re- CGRP-containing cells with nicotinic fast EPSPs and/or CGRP- sponses of second-order cells to transmitters released by ex- mediated slow EPSPs. Slow EPSPs are necessary for excita- cited primary afferent neurons. After all stimuli, fast and slow tion to spread within the submucosal plexus. Because some EPSPs were abolished by a 5-HT1P antagonist, N-acetyl-5- second-order neurons contain also CGRP,primary afferent neu- hydroxytryptophyl-5-hydroxytryptophan amide, and by 1.0 ␮M rons may be multifunctional and also serve as interneurons.
    [Show full text]
  • Practical Approaches to Dysphagia Caused by Esophageal Motor Disorders Amindra S
    Practical Approaches to Dysphagia Caused by Esophageal Motor Disorders Amindra S. Arora, MB BChir and Jeffrey L. Conklin, MD Address nonspecific esophageal motor disorders (NSMD), diffuse Division of Gastroenterology and Hepatology, Mayo Clinic, esophageal spasm (DES), nutcracker esophagus (NE), 200 First Street SW, Rochester, MN 55905, USA. hypertensive lower esophageal sphincter (hypertensive E-mail: [email protected] LES), and achalasia [1••,3,4••,5•,6]. Out of all of these Current Gastroenterology Reports 2001, 3:191–199 conditions, only achalasia can be recognized by endoscopy Current Science Inc. ISSN 1522-8037 Copyright © 2001 by Current Science Inc. or radiology. In addition, only achalasia has been shown to have an underlying distinct pathologic basis. Recent data suggest that disorders of esophageal motor Dysphagia is a common symptom with which patients function (including LES incompetence) affect nearly present. This review focuses primarily on the esophageal 20% of people aged 60 years or over [7••]. However, the motor disorders that result in dysphagia. Following a brief most clearly defined motility disorder to date is achalasia. description of the normal swallowing mechanisms and the Several studies reinforce the fact that achalasia is a rare messengers involved, more specific motor abnormalities condition [8•,9]. However, no population-based studies are discussed. The importance of achalasia, as the only exist concerning the prevalence of most esophageal motor pathophysiologically defined esophageal motor disorder, disorders, and most estimates are derived from people with is discussed in some detail, including recent developments symptoms of chest pain and dysphagia. A recent review of in pathogenesis and treatment options. Other esophageal the epidemiologic studies of achalasia suggests that the spastic disorders are described, with relevant manometric worldwide incidence of this condition is between 0.03 and tracings included.
    [Show full text]
  • Building a Second Brain in the Bowel
    Building a second brain in the bowel Marina Avetisyan, … , Ellen Merrick Schill, Robert O. Heuckeroth J Clin Invest. 2015;125(3):899-907. https://doi.org/10.1172/JCI76307. Review Series The enteric nervous system (ENS) is sometimes called the “second brain” because of the diversity of neuronal cell types and complex, integrated circuits that permit the ENS to autonomously regulate many processes in the bowel. Mechanisms supporting ENS development are intricate, with numerous proteins, small molecules, and nutrients that affect ENS morphogenesis and mature function. Damage to the ENS or developmental defects cause vomiting, abdominal pain, constipation, growth failure, and early death. Here, we review molecular mechanisms and cellular processes that govern ENS development, identify areas in which more investigation is needed, and discuss the clinical implications of new basic research. Find the latest version: https://jci.me/76307/pdf The Journal of Clinical Investigation REVIEW SERIES: ENTERIC NERVOUS SYSTEM Series Editor: Rodger Liddle Building a second brain in the bowel Marina Avetisyan,1 Ellen Merrick Schill,1 and Robert O. Heuckeroth2 1Washington University School of Medicine, St. Louis, Missouri, USA. 2Children’s Hospital of Philadelphia Research Institute and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA. The enteric nervous system (ENS) is sometimes called the “second brain” because of the diversity of neuronal cell types and complex, integrated circuits that permit the ENS to autonomously regulate many processes in the bowel. Mechanisms supporting ENS development are intricate, with numerous proteins, small molecules, and nutrients that affect ENS morphogenesis and mature function. Damage to the ENS or developmental defects cause vomiting, abdominal pain, constipation, growth failure, and early death.
    [Show full text]
  • Neural Control of Swallowing
    AG-2018-48 REVIEW dx.doi.org/10.1590/S0004-2803.201800000-45 Neural control of swallowing Milton Melciades Barbosa COSTA Received 11/4/2018 Accepted 9/5/2018 ABSTRACT – Background – Swallowing is a motor process with several discordances and a very difficult neurophysiological study. Maybe that is the reason for the scarcity of papers about it. Objective – It is to describe the chewing neural control and oral bolus qualification. A review the cranial nerves involved with swallowing and their relationship with the brainstem, cerebellum, base nuclei and cortex was made. Methods – From the reviewed literature including personal researches and new observations, a consistent and necessary revision of concepts was made, not rarely conflicting. Re- sults and Conclusion – Five different possibilities of the swallowing oral phase are described: nutritional voluntary, primary cortical, semiautomatic, subsequent gulps, and spontaneous. In relation to the neural control of the swallowing pharyngeal phase, the stimulus that triggers the pharyngeal phase is not the pharyngeal contact produced by the bolus passage, but the pharyngeal pressure distension, with or without contents. In nutritional swallowing, food and pressure are transferred, but in the primary cortical oral phase, only pressure is transferred, and the pharyngeal response is similar. The pharyngeal phase incorporates, as its functional part, the oral phase dynamics already in course. The pharyngeal phase starts by action of the pharyngeal plexus, composed of the glossopharyngeal (IX), vagus (X) and accessory (XI) nerves, with involvement of the trigeminal (V), facial (VII), glossopharyngeal (IX) and the hypoglossal (XII) nerves. The cervical plexus (C1, C2) and the hypoglossal nerve on each side form the ansa cervicalis, from where a pathway of cervical origin goes to the geniohyoid muscle, which acts in the elevation of the hyoid-laryngeal complex.
    [Show full text]
  • Lecture Series Gastrointestinal Tract
    Lecture series Gastrointestinal tract Professor Shraddha Singh, Department of Physiology, KGMU, Lucknow INNERVATION OF GIT • 1.Intrinsic innervation-1.Myenteric/Auerbach or plexus Local 2.Submucosal/Meissners plexus 2.Extrinsic innervation-1.Parasympathetic or -2.Sympathetic Higher centre Enteric Nervous System - Lies in the wall of the gut, beginning in the esophagus and - extending all the way to the anus - controlling gastrointestinal movements and secretion. - (1) an outer plexus lying between the longitudinal and circular muscle layers, called the myenteric plexus or Auerbach’s plexus, - controls mainly the gastrointestinal movements - (2) an inner plexus, called the submucosal plexus or Meissner’s plexus, that lies in the submucosa. - controls mainly gastrointestinal secretion and local blood flow Enteric Nervous System - The myenteric plexus consists mostly of a linear chain of many interconnecting neurons that extends the entire length of the GIT - When this plexus is stimulated, its principal effects are - (1) increased tonic contraction, or “tone,” of the gut wall, - (2) increased intensity of the rhythmical contractions, - (3) slightly increased rate of the rhythmical contraction, - (4) increased velocity of conduction of excitatory waves along the gut wall, causing more rapid movement of the gut peristaltic waves. - Inhibitory transmitter - vasoactive intestinal polypeptide (VIP) - pyloric sphincter, sphincter of the ileocecal valve Enteric Nervous System - The submucosal plexus is mainly concerned with controlling function within the inner wall - local intestinal secretion, local absorption, and local contraction of the submucosal muscle - Neurotransmitters: - (1) Ach (7) substance P - (2) NE (8) VIP - (3)ATP (9) somatostatin - (4) 5 – HT (10) bombesin - (5) dopamine (11) metenkephalin - (6) cholecystokinin (12) leuenkephalin Higher centre innervation - the extrinsic sympathetic and parasympathetic fibers that connect to both the myenteric and submucosal plexuses.
    [Show full text]