THE DIGESTIVE SYSTEM: Introduction and Upper GI

Total Page：16

File Type：pdf, Size：1020Kb

THE DIGESTIVE SYSTEM: Introduction and upper GI Dalay Olson Ph.D Office: Jackson Hall 3-120 Office hours: Monday 2-3pm INTRODUCTION TO GI LEARNING OBJECTIVES 3 Distinguish between the wall layers of the esophagus and those classically represented by the small intestine. ESOPHAGUS STRUCTURE UPPER THIRD ESOPHAGUS STRUCTURE LOWER TWO-THIRDS 4 Describe the voluntary and reflex components of swallowing. PHASES OF SWALLOWING Swallowing is integrated in the medulla oblongata. Voluntary Phase Pharyngeal Phase Esophageal Phase The swallowing reflex requires input from sensory afferent nerves, somatic motor nerves and autonomic nerves. VOLUNTARY PHASE The tongue pushes the bolus of food back and upwards towards the back of the mouth. Once the food touches the soft palate and the back of the mouth it triggers the swallowing reflex. This is the stimulus! PHARYNGEAL PHASE • Once the food touches the soft palate and the back of the mouth it triggers the swallowing reflex. This is the stimulus! • The medulla oblongata (control center) then initiates the swallowing reflex causing the soft palate to elevate, closing of the glottis and opening of the esophageal sphincter (response). • Once the food moves into the esophagus the sphincter closes once again. The glottis then opens again and breathing resumes. ESOPHAGEAL PHASE 1. Food moves along the esophagus by peristalsis (waves of smooth muscle contractions) • If the food gets stuck, short reflexes will continue peristalsis. • Myogenic reflex (you will learn about this later) produces contractions that move food forward. 2. As the bolus of food moves toward the stomach the lower esophageal sphincter relaxes and opens allowing the food to move into the stomach. Why is the swallowing reflex a long reflex? 5 Describe the local peristaltic reflexes that occur in the esophagus in response to stretch. Two distinct pathways! FIRST WAY: MYOGENIC REFLEX ALL HAPPENING WITHIN ONE CELL! The Myogenic Reflex (Everything happening within one cell!) Stretch! CELLULAR LEVEL SUBCELLULAR LEVEL Smooth muscles themselves can sense stretch and respond by contracting. The Second Way 1. A cell expressing mechanoreceptors sensitive to stretch (the stimulus) actovate the sensory neuron (“afferent fibers”). 2. Sensory neruons send a signal to the enteric nervous system (integrating center) 3. Myenteric plexus serves as the (“efferent fibers”) innervating smooth muscle (effector). 4. Smooth muscle (effector) contracts in response to the ENS input. Multiple cell types involved!! 6 Describe how the closing of the LES is aided by positive abdominal pressure. Predict how the closing of the LES is altered with displacement into the thoracic cavity. Make the connection between LES function and gastric reflux disease. LOWER ESOPHAGEAL SPHINCTER (LES) The LES is located outside of the thoracic cavity. Why does that matter? Because the LES is located outside of the thoracic cavity it experiences normal atmospheric pressure which helps hold the LES closed forming a barrier between the acid and the esophagus. What is GERD? Who is susceptible? INTRODUCTION TO GI LEARNING OBJECTIVES.

Copy Link

Recommended publications

IDP Biological Systems Gastrointestinal System
IDP Biological Systems Gastrointestinal System Section Coordinator: Jerome W. Breslin, PhD, Assistant Professor of Physiology, MEB 7208, 504-568-2669, [email protected] Overall Learning Objectives 1. Characterize the important anatomical features of the GI system in relation to GI function. 2. Describe the molecular and cellular mechanisms underlying GI motility. Highlight the neural and endocrine regulatory mechanisms. Characterize the different types of GI motility in different segments of the GI tract. 3. Define the major characteristics and temporally relate the cephalic, gastric, and intestinal phases of GI tract regulation. 4. For carbohydrates, proteins, fats, vitamins, minerals, and oral drugs, differentiate the processes of ingestion, digestion, absorption, secretion, and excretion, including the location in the GI tract where each process occurs. 5. Contrast the sympathetic and parasympathetic modulation of the enteric nervous system and the effector organs of the GI tract. 6. Describe the similarities and differences in regulating gastrointestinal function by nerves, hormones, and paracrine regulators. Include receptors, proximity, and local vs. global specificity. 7. Understand the basic mechanisms underlying several common GI disorders and related treatment strategies. Learning Objectives for Specific Hours: Hour 1 – Essential Concepts: Cellular transport mechanisms and Mechanisms of Force Generation 1. Describe the composition of cell membranes and how distribution of phospholipids and proteins influence membrane permeability of ions, hydrophilic, and hydrophobic compounds. 2. Using a cell membrane as an example, define a reflection coefficient, and explain how the relative permeability of a cell to water and solutes will generate osmotic pressure. Contrast the osmotic pressure generated across a cell membrane by a solution of particles that freely cross the membrane with that of a solution with the same osmolality, but particles that cannot cross the cell membrane.
[Show full text]
Pathophysiology, 6Th Edition
McCance: Pathophysiology, 6th Edition Chapter 38: Structure and Function of the Digestive System Key Points – Print SUMMARY REVIEW The Gastrointestinal Tract 1. The major functions of the gastrointestinal tract are the mechanical and chemical breakdown of food and the absorption of digested nutrients. 2. The gastrointestinal tract is a hollow tube that extends from the mouth to the anus. 3. The walls of the gastrointestinal tract have several layers: mucosa, muscularis mucosae, submucosa, tunica muscularis (circular muscle and longitudinal muscle), and serosa. 4. Except for swallowing and defecation, which are controlled voluntarily, the functions of the gastrointestinal tract are controlled by extrinsic and intrinsic autonomic nerves (enteric plexus) and intestinal hormones. 5. Digestion begins in the mouth, with chewing and salivation. The digestive component of saliva is α-amylase, which initiates carbohydrate digestion. 6. The esophagus is a muscular tube that transports food from the mouth to the stomach. The tunica muscularis in the upper part of the esophagus is striated muscle, and that in the lower part is smooth muscle. 7. Swallowing is controlled by the swallowing center in the reticular formation of the brain. The two phases of swallowing are the oropharyngeal phase (voluntary swallowing) and the esophageal phase (involuntary swallowing). 8. Food is propelled through the gastrointestinal tract by peristalsis: waves of sequential relaxations and contractions of the tunica muscularis. 9. The lower esophageal sphincter opens to admit swallowed food into the stomach and then closes to prevent regurgitation of food back into the esophagus. 10. The stomach is a baglike structure that secretes digestive juices, mixes and stores food, and propels partially digested food (chyme) into the duodenum.
[Show full text]
Swallowing Problems 575 S 70Th Street, Suite 440 Lincoln, NE 68510 402.484.5500
Swallowing Problems 575 S 70th Street, Suite 440 Lincoln, NE 68510 402.484.5500 Swallowing problems may result in accumulation of solids or liquids in the throat that may complicate or feel like post-nasal drip. When the nerve and muscle interaction in the mouth, throat and food passage (esophagus) aren’t working properly, overflow secretions can spill into the voice box (larynx) and breathing passages (trachea and bronchi) causing hoarseness, throat clearing or cough. Several factors contribute to swallowing problems: With age, swallowing muscles often lose strength and coordination. Thus, even normal secretions may not pass smoothly into the stomach. During sleep, swallowing is less frequent, and secretions may gather. Coughing and vigorous throat clearing are often needed when awakening. When nervous or under stress, throat muscles can trigger spasms that feel like a lump in the throat. Frequent throat clearing, which usually produces little or no mucus, can make the problem worse by increasing irritation. Growths or swelling in the food passage can slow or prevent the movement of liquids and/or solids. Swallowing problems can also be called by gastroesophageal reflux disease (GERD). This is a return of stomach contents and acid into the esophagus or throat. Heartburn, indigestion and sore throat are common symptoms. GERD may be aggravated by lying down, especially following eating. Hiatal hernia, a pouch-like tissue mass where the esophagus meets the stomach, often contributes to the reflux. Post-nasal drip often leads to a sore, irritated throat. Although there is usually no infection, the tonsils and other tissues in the throat may swell.
[Show full text]
Respiratory Issues in Rett Syndrome Dr. Marianna Sockrider, Pediatric
RettEd Q&A: Respiratory Issues in Rett Syndrome Dr. Marianna Sockrider, Pediatric Pulmonologist, Texas Children's Hospital Webcast 02/13/2018 Facilitator: Paige Nues, Rettsyndrome.org Recording link: https://register.gotowebinar.com/recording/1810253924903738120 Attendee Questions Response Breathing Irregularities Why is breathing so funny when our girls/ A behavioral arousal can trigger breathing abnormalities in Rett boys wake up, almost as if startled? syndrome. A person goes through stages of sleep and particularly if aroused from a deep sleep state (REM) may be more disoriented or startled. This can trigger the irregular breathing. Could she address the stereotypical You may observe breathing abnormalities like breath holding breathing abnormalities such as gasping and hyperventilation more with the stress of an acute and breath holding and how they play a respiratory illness. Breath holding and hyperventilation do not part in respiratory illness? directly cause respiratory illness. If a person has difficulty with swallowing and has these breathing episodes while trying to eat or drink, aspiration could occur which can cause respiratory symptoms. If one has very shallow breathing, especially when there is more mucus from acute infection, it may be more likely to build up in the lower lungs causing airway obstruction and atelectasis (collapse of some air sacs). Is there any evidence (even anecdotal) Frequent breath-holding and hyperventilation has been Reference 1 that breathing patterns change in Rett reported to become less evident with increasing age though it is patients over time? not certain whether this could be that families are used to the irregular breathing and don’t report it as much or that it is the people who live longer who are less symptomatic.
[Show full text]
Silent Reflux (Also Called LPR Or EOR)
Silent reflux (also called LPR or EOR) This leaflet explains what your condition is, why it happens, what the symptoms are and how it can be managed. If there is anything you don’t understand or if you have any further questions please talk to your doctor or nurse. What is silent reflux? Everyone has juices in the stomach which are acidic and digest and break down food. At the top of the stomach there is a muscular valve which closes to prevent food and stomach juices escaping upwards into the gullet. If this muscular valve (oesophageal sphincter) does not work very well, the stomach juices can leak backwards into the gullet, causing reflux or symptoms of indigestion (heartburn). However, in some people, small amounts of stomach juice can spill even further back into the back of your throat, affecting the throat lining and your voice box (larynx) and causing irritation and hoarseness. This is known as laryngo pharyngeal reflux (LPR) or extra oesophageal reflux (EOR). Its common name is 'silent reflux' because many people do not experience any of the classic symptoms of heartburn or indigestion. Silent reflux can occur during the day or night, even if a person hasn't eaten anything. Usually, however, silent reflux occurs at night. What are the symptoms of silent reflux? The most common symptoms are: • A sensation of food sticking or a feeling of a lump in the throat. • A hoarse, tight or 'croaky' voice. • Frequent throat clearing. • Difficulty swallowing (especially tablets or solid foods). • A sore, dry and sensitive throat. • Occasional unpleasant "acid" or "bilious" taste at the back of the mouth.
[Show full text]
Mucus Secretion in the Trachea. H
269 MUCUS SECRETION IN THE TRACHEA. H. FLOREY,* H. M. CARLETON AND A. Q. WELLS. From the Department of Pathology, Cambridge; and the Department of Physiology, Oxford. Received for publication March 24th, 1932. IN the trachea and bronchi there are two distinct sets of glands producing mucus. As shown in Fig. 1, goblet-cells are fairly numerous in the tracheal mucosa of the cat. Usually they give a typical red coloration with muci- carmine. Empty, collapsed goblet-cells, not giving this reaction, may often be observed. These cells are absent over the posterior tracheal fold. There are found, in addition, acini of gland-cells lying in the submucosa. These cell-groups are serous, mucous or mixed in type. The submucosal glands, in contrast with the goblet-cells, have been shown to be innervated (Larsell, 1923). These present experiments have had as their object the determination of the conditions in which mucus is discharged from these two groups of glands, and the observation of the histological changes involved in their activity. EXPERIMENTAL. Cats have been used almost exclusively for these investigations. The various methods employed will be described under the different experiments. Effect8 of Stimulation of Nerte8. A straight tracheal cannula was inserted into a cat, anawsthetized by dial or chloralose, or decerebrated. One vagus nerve was dissected in the neck, tied and cut. During a control period of 3 hours it was observed that no obvious mucus collected in the cannula. The peripheral end of the vagus was then stimulated faradically, each stimulus lasting 1 1/5 seconds, with an intervening rest period of 1 second.
[Show full text]
Response of the Human Cardiac Sphincter to Circulating Prostaglandins F2a and E2 and to Anti- Inflammatory Drugs
Gut: first published as 10.1136/gut.16.2.137 on 1 February 1975. Downloaded from Gut, 1975, 16, 137-143 Response of the human cardiac sphincter to circulating prostaglandins F2a and E2 and to anti- inflammatory drugs J. B. DILAWARI1, A. NEWMAN2, J. POLEO3, AND J. J. MISIEWICZ From the MRC Gastroenterology Unit, Central Middlesex Hospital, London, NW1O 7NS SUMMARY The effects on intraluminal pressure in the oesophagus, the cardiac sphincter, and the gastric fundus of intravenous prostaglandin F2a, E2, and of rectal indomethacin were studied in 41 subjects. Intravenous infusion of prostaglandin F2a (005 to 0-8 ,tg kg-' min-') produced marked, dose-related and sustained elevation of cardiac sphincter pressure without significantly affecting oesophageal peristalsis or gastric fundal motility. Sphincteric relaxation during swallowing was prolonged. Plasma gastrin levels were unchanged. Intravenous infusion of PGE2 (0-08 ,tg kg-' min-') inhibited sphincter contractions to serial bolus intravenous injections of pentagastrin (0.1 or 0-2 ,ug kg-'). Rectal indomethacin (200 mg) resulted in a rise of cardiac sphincter pressure, suggesting that endogenous synthesis of an inhibitory (E-type) prostaglandin was suppressed. The results indicate that prostaglandin E2 may be concerned in the regulation of cardiac sphincter tone in man, whilst prostaglandin F2a may be useful in the treatment of gastrooesophageal reflux. Pressure level in the cardiac sphincter plays a part lumen tube assembly in the oesophagus, the cardiac in the prevention of gastrooesophageal reflux and sphincter, and the gastric fundus of fasting mile http://gut.bmj.com/ depends upon the tone of circular oesophageal subjects reclining in the supine position.
[Show full text]
Section IX – Digestive System
Section IX – Digestive System The digestive system refers to the alimentary canal or gastrointestinal tract. It consists of organs and glands that break down food products to be used by the body as a source of energy through absorption of nutrients and to eliminate solid waste products. The GI tract begins at the mouth, where food is ingested and ends at the anus, where waste products are eliminated from the body. Medical Terms Combining Forms gingiv/o gums stomat/o, or/o mouth dent/o, odont/o teeth labi/o lip maxill/o jaw sial/o saliva, salivary glands abdomin/o abdomen gastr/o stomach lingu/o, gloss/o tongue myc/o fungus orth/o straight esophag/o esophagus carcin/o cancer rect/o rectum proct/o rectum and anus sigmoid/o sigmoid ile/o ileum col/o colon duoden/o duodenum enter/o intestine hepat/o liver chol/e, chol/o bile, gall cholecyst/o gall bladder pancreat/o pancreas cyst/o bladder an/o anus Suffixes -rrhea discharge, flow -orexia appetite -emesis vomiting -pepsia digestion -phagia swallowing, eating -lith stone Medical Terms Mouth (or/o, stomat/o) or/al, stomat/ic – pertaining to the mouth stomat/o/dynia – pain in the mouth sub/lingu/al – pertaining to under the tongue sub/maxill/ary – pertaining to under the jaw Salivary Glands (sial/o) sial/o/rrhea – excessive flow of saliva sial/o/aden/itis – inflammation of the salivary glands Teeth (odont/o, dent/o) dent/ist – specialist in the study of teeth orth/o/dont/ist – specialist in straight teeth gingiv/itis – inflammation of the gums Stomach (gastr/o) gastr/o/dynia – pain in the stomach
[Show full text]
Protective Effects of Amniotic Fluid in the Setting of Necrotizing Enterocolitis
Review nature publishing group Protective effects of amniotic fluid in the setting of necrotizing enterocolitis Soham Dasgupta1 and Sunil Kumar Jain1 Necrotizing enterocolitis (NEC) is the most common life cost of taking care of medical NEC was $74,004 and surgical threatening condition affecting preterm infants. NEC occurs in NEC was $198,040 per infant, respectively (8). 1–5% of all neonatal intensive care admissions and 5–10% of After more than half a century of NEC research in animal very low birth weight infants. The protective role of human models and in vitro research, we could not find a “magic breast milk (BM) has been well established. It has also been bullet” to prevent NEC. However, in last decade the most shown that amniotic fluid (AF) and BM have many similarities effective tools to decrease burden of NEC have been NEC in terms of presence of growth and other immune- prevention initiatives like breast milk (BM) feeding, blood modulatory factors. This finding led to the initial hypothesis transfusion guidelines, and antibiotics stewardship in PI that AF may exert similar protective effects against the (3,9,10). During fetal life, fetal intestine gets exposed to high development of NEC, as does BM. Multiple studies have concentrations of many trophic factors by swallowing AF. But elucidated the presence of growth factors in AF and the preterm birth interrupts AF swallowing, which deprives the protective effect of AF against NEC. Studies have also intestine of PI of these trophic factors. In this review, we will described possible mechanisms how AF protects against review the role of various trophic factors and cytokines in the NEC.
[Show full text]
GI Motility-I (Deglutition and Motor Functions of Stomach)
Lecture series Gastrointestinal tract Professor Shraddha Singh, Department of Physiology, KGMU, Lucknow GASTROINTESTINAL MOTILITY-1 (Deglutation and motor function of stomach) Mastication (Chewing) - the anterior teeth (incisors) providing a strong cutting action and the posterior teeth (molars), a grinding action – canine tearing - All the jaw muscles working together can close the teeth with a force as great as 25 Kg on the incisors and 90 Kg on the molars. - Most of the muscles of chewing are innervated by the motor branch of the 5th cranial nerve, and the chewing process is controlled by nuclei in the brain stem. - Stimulation of areas in the hypothalamus, amygdala, and even the cerebral cortex near the sensory areas for taste and smell can often cause chewing Chewing Reflex - The presence of a bolus of food in the mouth at first initiates reflex inhibition of the muscles of mastication, which allows the lower jaw to drop. ↓ - The drop in turn initiates a stretch reflex of the jaw muscles that leads to rebound contraction ↓ - raises the jaw to cause closure of the teeth ↓ - compresses the bolus again against the linings of the mouth, which inhibits the jaw muscles once again Chewing Reflex - most fruits and raw vegetables because these have indigestible cellulose membranes around their nutrient portions that must be broken before the food can be digested - Digestive enzymes act only on the surfaces of food particles - grinding the food to a very fine particulate consistency prevents excoriation of the GIT (Stomach) Swallowing (Deglutition)
[Show full text]
Ab133033 – Gastrin 1 (GAST) Human ELISA Kit
ab133033 – Gastrin 1 (GAST) Human ELISA Kit Instructions for Use For quantitative detection of Gastrin 1 (GAST) in tissue culture media, Human serum and Plasma (citrate). This product is for research use only and is not intended for diagnostic use. Version 5 Last Updated 5 July 2018 Table of Contents INTRODUCTION 1. BACKGROUND 2 2. ASSAY SUMMARY 4 GENERAL INFORMATION 3. PRECAUTIONS 5 4. STORAGE AND STABILITY 6 5. MATERIALS SUPPLIED 6 6. MATERIALS REQUIRED, NOT SUPPLIED 7 7. LIMITATIONS 7 8. TECHNICAL HINTS 8 ASSAY PREPARATION 9. REAGENT PREPARATION 9 10. STANDARD PREPARATIONS 10 11. SAMPLE COLLECTION AND STORAGE 12 12. PLATE PREPARATION 14 ASSAY PROCEDURE 13. ASSAY PROCEDURE 15 DATA ANALYSIS 14. CALCULATIONS 17 15. TYPICAL DATA 18 16. TYPICAL SAMPLE VALUES 19 17. ASSAY SPECIFICITY 21 RESOURCES 18. TROUBLESHOOTING 22 19. NOTES 23 Discover more at www.abcam.com 1 INTRODUCTION 1. BACKGROUND Abcam’s Gastrin 1 (GAST) in vitro competitive ELISA (Enzyme-Linked Immunosorbent Assay) kit is designed for the accurate quantitative measurement of Gastrin 1 (GAST) in tissue culture media, Human serum and Plasma (citrate). A goat anti-rabbit IgG antibody has been precoated onto 96-well plates. Standards or test samples are added to the wells, along with an alkaline phosphatase (AP) conjugated-Gastrin 1 antigen and a polyclonal rabbit antibody specific to Gastrin 1. After incubation the excess reagents are washed away. pNpp substrate is added and catalyzed by AP to produce a yellow color. The optical density of the yellow coloration at 405 nm is inversely proportional to the amount of Gastrin 1 captured in the plate.
[Show full text]
Digestive System (Part-I)
NPTEL – Basic Courses – Basic Biology Lecture 11: Digestive System (Part-I) Introduction: The collective processes by which a living organism takes food which are necessary for their growth, maintenance and energy needs is called nutrition. The chemical substances present in the food are called nutrients. DIFFERENT MODE OF NUTRITION IN ORGANISMS: It is important to know the different modes of nutrition in all living organisms in order to understand energy flow within the ecosystem. Plant produces high energy organic food from inorganic raw materials. They are called autotroph and the mode of nutrition is known as autotrophic nutrition. Animals feed on those high energy organic food, are called as heterotrophs and their mode of nutrition is known as heterotrophic nutrition Heterotrophic nutrition further sub-categorise in holozoic, parasitic, and saprophytic mode of nutrition based on the pattern and class of food that is taken inside. Holozoic Nutrition: It involves taking entire organic food and this can be in the form of whole part of plant or animal. Most of the free living protozoans, humans and other animals fall under this category. Saprophytic Nutrition: The organism fulfils the requirement of food from the rotten parts of dead organisms and decaying matter. The organisms secrete digestive enzymes outside the body on their food and then take in digested food. It is a kind of extra-cellular digestion. Examples: Housefly, Spiders etc. Parasitic Nutrition: The organism fulfils the requirement of food from the body of another organism. The parasites are of two distinct types, one which lives inside the host and the other which lives outside.
[Show full text]