Physiology of the Mouth - Oesophagus PDF

Physiology of the mouth - oesophagus MUHAMMAD ALBAHADILI MBChB CABS HDLM 2023 - 2024 The Physiology of the Mouth: Ingestion: The mouth is the way into the gastrointestinal tract Digestion Mechanical: Physical disruption of food is by mastication. The inci...

Physiology of the mouth - oesophagus MUHAMMAD ALBAHADILI MBChB CABS HDLM 2023 - 2024 The Physiology of the Mouth: Ingestion: The mouth is the way into the gastrointestinal tract Digestion Mechanical: Physical disruption of food is by mastication. The incisors cut food into pieces and the molars crush it and mix it with saliva to form a bolus. chewing is important for most fruits and raw vegetables because they have indigestible cellulose membranes around their nutrient portions that must be broken before the food can be digested. Because the digestive enzymes act only on the surfaces of food particles (Teeth hold, cut, tear, and grind our food) Lips and cheeks hold food in the mouth and, with the help of the tongue, put food between teeth for chewing. The mouth muscles and the movement of the jaw are also necessary for proper mastication. Saliva moistens and softens food to facilitate chewing and swallowing  The tongue moves food around the mouth and finally gathers the chewed food into a ball (bolus), before moving it to the back of the mouth for swallowing. Chemical: An enzyme in saliva (amylase) Another function of saliva protect the oral environment, ensuring a moist, chemically appropriate environment with healthy bacterial flora, facilitating speech Other functions of the oral cavity: Oral competence – ability to hold food & saliva in the mouth without drooling Start swallowing by the closure of the lips When food is ready for swallowing, the tongue & the oral cavity components (hard & soft palates) push the food to the back towards the oropharynx and oesophagus; palatoglossus & palatopharyngeus muscles have a role in swallowing – soft palate raised to close the nasopharynx & prevents food from entering the nasal cavity Tongue, cheeks & lips assist in speech FUNCTIONS OF THE MOUTH Mastication; Chemical digestion Parts involved in ? Parts involved in ? Nerves involved in ? Nerves involved in ? Taste Absorption Parts involved in ? Swallowing Nerves involved in ? Parts involved in ? Nerves involved in ?  The Physiology of pharynx ⚫ Deglutition (swallowing) ⚫ Parts involved in ⚫ Nerve involved in ⚫ What are the steps of ⚫ Respiration ⚫ Vocal resonance ⚫ Secretion of mucus to lubricate the pharynx ⚫ Provides drainage to nose, oral cavity, middle ear ⚫ Local defense and immunity (Waldeyer’s ring) The Physiology of esophagus Swallowing: in the oesophageal phase, Which nerve (s) control the a wave of peristalsis sweeps down the esophageal swallowing activity ? oesophagus, propelling the bolus to the Steps of esophageal swallowing stomach in about 9 seconds Mucus layer which helps in the Closure of UES movements of the bolus during Primary peristalses peristalsis. Secondary peristalses swallowing It’s a process in which the food and liquid pass from back of the mouth to the stomach It is an “all-or-nothing” reflex It is initiated voluntarily but once it is started, it cannot be stopped what are the steps of normal swallowing? We can divide the swallowing in Oral Pharyngeal Oesophageal MOUTH: PREPARATORY LIPS TEETH CHEEKS TONGUE SOFT PALATE PHARYNEAL PHASE Nervous Initiation of the Pharyngeal Stage of Swallowing: The most sensitive tactile areas of the posterior mouth and pharynx for initiating the pharyngeal stage of swallowing lie in a ring around the pharyngeal opening, with greatest sensitivity on the tonsillar pillars. TONGUE SOFTPALATE VOCAL CORDS & EPIGLOTIS HYOID BONE & LARYNX MUSCLES OF PHARYNX Pharyngeal muscles Longitudinal Circular (constrictors) elevate the larynx & shorten and Pharyngeal constrictors widen of the pharynx during contraction act sequentially from swallowing the superior > inferior propelling the food bolus into oesophagus At the pharyngoesophageal junction there is a constriction of the inferior constrictor muscle to form the ‘superior oesophageal sphincter’ Oesophagus phase Swallowing Resting DYSPHAGIA Dysphagia Definition of dysphagia its Symptom “difficulty in swallowing” and should be differentiated from; Odynophagia: painful swallowing Globus: sensation of lump in the throat Phagophobia: psychogenic dysphagia Regurgitation: reflux of stomach content to pharynx Gagging: food inducing vomiting  Normal swallowing Oral Pharyngeal oesophageal So: The dysphagia either Oral Pharyngeal oesophageal Causes: In the oropharyngeal part Painful conditions Acute tonsillitis Glandular fever Acute pharygolaryngeal oedema Ludwig s angina Neurological conditions Cranial nerves (3nd division of 5th,7th, 9th,10th,11th , 12th ) damage multiple sclerosis, muscular dystrophy, or Parkinson's disease. Surgery in neck Retropharyngeal abscess Pharyngeal pouch Tumours oropharynx, hypopharynx Causes: In oesophageal part In the lumen: Foreign body Drugs Gastroesophageal reflux In the wall: Sideropenic dysphagia Inflammation Tumour Motility disorders- achalasia, diffuse oesophageal spasm Mallory-Weiss syndrome Iatrogenic From outside of oesophgus: Rolling hiatus hernia Retrosternal goitre Any mass in the chest Causes? Foreign body drugs Mass tumour Symptoms Signs Difficulty chewing Food spills from lips; excessive mastication time of soft food; poor dentition; tongue; jaw or lip weakness. Difficulty initiating swallow Mouth dryness (xerostomia); lip or tongue weakness Nasal regurgitation Bolus enters the nasal cavity as seen on radiographic swallowing study Coughing in swallow material enters the air way on radiographic study Regurgitation Undigested food in the mouth; radiographic study shows food returning from esophagus to pharynx Imp questions to ask? (History of the disease) When did it start? Any history of surgery in neck Solids and liquids from start? or chest Did it painful? Dribbling Vomiting, Weight loss cough Intermittent/constant and Regurgitation progressive History of stroke or TIA Difficult to start swallowing Any bulge in the neck during swallowing Achalasia Achalasia is a primary oesophgeal motility disorder Non-relaxing Lower oesophgeal sphincter and absent peristalsis in the body of the oesophagus  Pathophysiology Loss of ganglion cells [myenteric plexus] & loss of inhibitory neurons in lower oesophagus The cause is unknown, but may be viral induced autoimmune disease Histopathological study show chronic inflammation Parasitic infection Trypanosoma cruzi (Chagas disease)  5th and 6th decade but can be in Diagnosis: any age high index of suspicion is needed in the 1.8/100 000/ year diagnosis of achalasia as symptoms can be mild and chronic and can be easily Presents with dysphagia, mis-diagnosed as Gastro-Oesophageal regurgitation, weight loss, and overspill into the trachea, Reflux Disease especially at night leading to aspiration presented with cough.  How oesophagus is emptying in achalasia? Why gas bubble is not found in the stomach in the case of achalasia? What is pseudo-achalasia? chest X ray Achalasia normal Wide mediastinum No air in stomach “Bird's beak” appearance megaesophagus Endoscopy: Endoscopy typically shows frothy saliva pooling in the oesophagus and the presence of food residue. The oesophagus may be dilated and can be tortuous. The OGJ appears tight and spastic but can usually allow an endoscope to pass with gentle pressure. A normal endoscopy however does not exclude achalasia, as 30–40% of endoscopies are reported as normal before a final diagnosis of achalasia is made. Manometry: high resolution manometry The resting pressure in normal esophagus the procedure Pressure of LES 100 is considered achalasia Aperistalsis in esophageal body Relative increase in intra-esophageal pressure as compared with intra-gastric pressure Therapy of achalasia Pneumatic dilatation Heller’s myotomy Endoscopic myotomy Botulinum Medication calcium channel blockers (nifedipine) Nitrates (isosorbide) 5ʹ-phosphodiesterase inhibitors Endoscopic treatment pneumatic dilatation ► Heller’s myotomy  Peroral Endoscopic myotomy  Botulinum toxin injection Botulinum toxin (Botox) is a neurotoxic protein produced by the bacterium Clostridium botulinum and related species. It prevents the release of the neurotransmitter acetylcholine from axon endings at the neuromuscular junction, thus causing flaccid paralysis. It has temporary effect, its complication scar formation Hypercontractile motility disorders (Distal oesophageal spasm) It is a condition in which there are incoordinate, premature and rapidly propagated contractions of the oesophagus. causing dysphagia and/or chest pain. The condition may be dramatic, with marked hypertrophy of the circular muscle and a corkscrew oesophagus on the barium oesophagogram These abnormal contractions are more common in the distal two-thirds of the oesophageal body. Hypercontractile (jackhammer) oesophagus is characterized by high-amplitude contractions and should be differentiated from contractility disorder secondary to outfow obstruction. Patients may present with dysphagia or pain. Corkscrew oesophagus  Treatment same treatment protocols for achalasia Calcium channel blocker & pneumatic dilatation have only transient effects Surgical management for sever cases Gastro-oesophageal reflux disease Gastro-oesophageal reflux disease Pathophysiology Investigations Complications Treatment Mechanisms that prevent reflux: High pressure zone (sphincter) Resting pressure of LOS = 10-45 (20) mmHg, Length of LOS = 3cm The mucosal rosette at the cardia (plug) Angle between esophagus and stomach (His) Diaphragmatic sling (crura) Intra-abdominal length of oesophagus = 2cm (high pressure area by positive intra-abdominal pr.  Lower oesophageal sphincter (LOS): maintain the competent LOS transient relaxation in swallowing, vomiting, vent swallowed air Physiological reflux? Pathological reflux? hiatus hernia is associated with GORD, how?! GORD acid reflux, is a condition where Resting pressure of LOS < stomach contents come back up 6mmHg into the oesophagus resulting in Length of LOS < 2cm either symptoms and/or Intra-abdominal length of complications oesophagus < 1cm  GORD symptoms Oesophgeal: Heartburn; burning sensation behind the sternum Regurgitation: reflux the gastric content into the mouth Epigastric pain radiated to back provoked by food (fat, spicy), exercise Haematemesis Dysphagia Odynophagia extraoesophageal: chest pain, asthma, dental erosion, cough Investigations In patients with classical symptoms the diagnosis can be made clinically Older patients [with recent onset of symptoms] require an endoscopy Patients with uncontrolled symptoms (not responded to Proton Pump Inhibitor (PPI) or dysphagia) should be investigated Oesophgeal endoscopy High resolution manometry HRM is useful in detecting major oesophageal motility disorder, e.g. achalasia, which can sometimes mimic GORD; defining the location of the LOS for accurate pH monitoring placement; assessing the function and morphology of the LOS, including the size of a hiatus hernia; assessing oesophageal body motility to tailor intervention, especially the various anti-refux procedures Oesophageal pH monitoring and manometry done for patient not respond to PPI or atypical symptoms Wireless pH monitoring record for 96 hours increase the test sensitivity and diagnosis A normal endoscopy does not exclude GORD (correlation between symptoms and endoscopy finding is poor) In patients with atypical or persist symptoms despite of therapy, oesophageal manometry and 24 hours pH recording Note: stop PPI for 2 week before pH recording The length and pressure of LOS are important CT scan for anatomy of LOS but not for GORD Barium contrast study give objective and dynamic assessment of oesophagogastric anatomy Complicated GORD: Oesophageal stricture Barrett’s oesophagus Barrett’s oesophagus Columnar transformation of squamous oesophageal epithelium Classical B. (>= 3cm columnar epithelium Short-segment B. (< 3cm) Precancerous condition ? risk  Screening intestinal metaplasia? How we can differentiated between Barrett or sliding hernia?  Treatment of GORD Endoscopic Reduction of weight, Sutures of gastric mucosa avoid heavy meal late at Injection of submucosal polymers night, alcohol, smoking, Ablation of mucosa only for tea or coffee dysplasia cases Laser Antacids Photodynamic Acid suppressants Argon-beam Plasma coagulation Histamine 2 receptor Radio-freqeuncy antagonists Endoscopic mucosal Proton pump resection inhibitors  Surgery Laparoscopic fundoplication is the most popular There are many operation for GORD but they are based on creation of an intraabdominal segment of oesophagus HRM and pH monitoring are recommended investigations before consideration of surgical treatment pH monitoring confrms GORD and HRM assesses oesophageal body function and LOS characteristics Oesophageal cancer Squamous and adenocarcinoma Squamous cell carcinoma is the most common but the adeno. is increasing Risk factors obesity Barrett’s Smoking alcohol Presented late Odynophagia, dysphagia, vomiting, weight loss are late symptoms, recurrent laryngeal n. paralysis, Horner syndrome, supraclavicular lymph nodes metastasis investigations Ba swallow endoscopy CT scan Barium swallow  CT scan endoscopy