Session 4 Gastrointestinal System 1 - Overview, Oral Cavity and Pharynx PDF

BDS Module 1 - Dental Anatomy Course Systems Overview: Gastrointestinal System Mr. Luke Reid ([email protected]) Professor Tracey Wilkinson ([email protected]) Intended learning outcomes By the end of the session students should be able to: Describe the ana...

BDS Module 1 - Dental Anatomy Course Systems Overview: Gastrointestinal System Mr. Luke Reid ([email protected]) Professor Tracey Wilkinson ([email protected]) Intended learning outcomes By the end of the session students should be able to: Describe the anatomy and functions of the GI tract and its associated organs. Describe how nutrients are carried from the intestine to the liver. How do I use these presentations? Work your way through the slides at your own speed. The slides have a voice-over which talks you through the content. Some of the labels are blank (the answers will not be given to you). This is to encourage you to do some reading of the subject, using your textbooks, Liebgott and/or Moore and Dalley. At intervals, you will be asked to check your understanding by answering the embedded questions. The answers to these will be given at the end of the presentations on the gastrointestinal system. Gastrointestinal system 1 Overview, oral cavity and pharynx  Gastrointestinal System - Components Oral Cavity The gastrointestinal tract is a continuous ‘tube’ commencing at the oral cavity and ending at the anus. Anus Gastrointestinal Tract - Components Head: Oral Cavity Pharynx Neck: Pharynx Oesophagus Thorax: Oesophagus _ _ _ _ _ _ _ _ _ _: Stomach _ _ _ _ _ _ intestine Large Intestine (most) Most accessory organs of GI Tract Pelvis: Rectum Perineum: Anal Canal Anus  Gastrointestinal System - Functions Oral Cavity Functions: 1. Introduce _ _ _ _ _ _ _ _ _ into the body 2. Digest and absorb nutrients (and toxins) 3. Excrete residual waste out of the body Anus  Gastrointestinal Tract - Functions ______ Oral Cavity: ______ Sensing Pharynx Salivation Chewing Initiating swallowing Oesophagus Pharynx: Defence against infection (tonsils) Swallowing Airway protection ______ Oesophagus: Transit from pharynx to stomach Small Intestine Stomach and small intestine: Transit Large Defence against infection (acid) Intestine Digestion and absorption (accessory organs of GI tract) Large Intestine and Anus: Transit Rectum Reabsorption of H2O & electrolytes Stool formation Anus Waste excretion  Oral Oesopha Small Large Pharynx Stomach Rectum Anus Cavity gus Intestine Intestine Oral Cavity _ _ _ _ palate Nasal Soft Cavity palate Oral Cavity Teeth (Dentition) Ton gu e ________ _ Muscle of the floor of the Hyoid mouth bone  Oral Oesopha Small Large Pharynx Stomach Rectum Anus Cavity gus Intestine Intestine Surface Anatomy of the Oral Cavity ________ _______ Hard palate Hard palate Soft palate Palatine Arches of tonsil soft palate Tongue Tongue Uvula Lower dental arch Gingiva  Oral Oesopha Small Large Pharynx Stomach Rectum Anus Cavity gus Intestine Intestine Mastication (chewing) Conducted by movement of the jaw and tongue, to break down food. Also facilitates taste and digestion by mixing food with saliva. Maxilla Upper Dentition (Teeth) Buccinator Tongue FOOD BOLUS Lower Dentition (Teeth) Mandible  Oral Oesopha Small Large Pharynx Stomach Rectum Anus Cavity gus Intestine Intestine Mastication LATERAL PTERYGOID (‘DEPRESSES’ MANDIBLE) TEMPORALIS (ELEVATES MANDIBLE) MEDIAL PTERYGOID (ELEVATES MANDIBLE) MASSETER (ELEVATES MANDIBLE) Movement of opening and closing the mouth occur by muscles acting on the temporomandibular joint (TMJ) to elevate Can you and depress the mandible. work out Controlled by the ‘muscles of mastication’ which Four muscles at each TMJ (3 close, 1 muscles of mastication opens the mouth) are shown  Oral Oesopha Small Large Pharynx Stomach Rectum Anus Cavity gus Intestine Intestine Adult Dentition Rig Le Upper ht ft Dental Arch 8 6 7 8 7 6 5 4 3 2 1 1 2 3 4 5 (Maxillary) Lower 5 4 3 3 4 5 8 7 6 2 1 1 2 6 7 8 Dental Arch (Mandibular) Molars Canin Incis 8 = Wisdom tooth (6, 7 & 8) Premolars e or (4 & 5) (3) (1 & 2) 32 teeth All erupted by age 18 4 quadrants (upper right; upper left; lower right & lower left)  Oral Oesopha Small Large Pharynx Stomach Rectum Anus Cavity gus Intestine Intestine Tongue Posterior one third Vertical part Anterior 2/3rds Posterio r 1/3rd nterior two thirds foliate papillae, Horizontal part _______ papillae & fungiform papillae (singular papilla) filiform papillae ALL with (touch, temperature, taste buds pain )  Oral Oesopha Small Large Pharynx Stomach Rectum Anus Cavity gus Intestine Intestine Tongue Moves tongue around during mastication, speech and swallowing Intrinsic muscles Extrinsic muscles Changes shape of the tongue Four pairs Attach tongue to bony skeleton  Oral Oesopha Small Large Pharynx Stomach Rectum Anus Cavity gus Intestine Intestine Salivary Glands Saliva is 99% water, but is a solute to allow tasting to occur. Contains a lubricant (mucin) to aid swallowing & speech and for keeping the mucosa moist It is a buffer for plaque acids Also contains antimicrobial elements Amylase to begin carbohydrate digestion!! Major Glands Minor Glands 3 bilateral pairs: - 1000s in oral mucosa - Parotid (‘near ear’) - Basal secretion (background - Submandibular ‘under mandible’ and continuous) to keep - Sublingual ‘under tongue’ mouth moist What stimulates salivation: 1. Thought, sight, smell of food or presence of food in the mouth. 2. Painful oral conditions eg. teething or fractured  Oral Oesopha Small Large Pharynx Stomach Rectum Anus Cavity gus Intestine Intestine Surface Anatomy of the Salivary Glands Parotid Gland Parotid duct crosses face; secretes into _ _ _ _ _ _ _ _ by upper 2nd molar Submandibular Gland Submandibular duct enters floor of mouth; secretes via sublingual caruncle Sublingual Gland Located in floor of mouth; secretes via several ducts superiorly Duct clogging/blockage can cause swelling, due to back up of secretions Sublingua l caruncle ASHED RED LINE = DUCT  Oral Oesopha Small Large Pharynx Stomach Rectum Anus Cavity gus Intestine Intestine Muscles of Facial Expression Lie between superficial fascia and facial skeleton Contraction causes skin of the face to be pulled into expressions Buccinator Tenses the cheek Align food between teeth Orbicularis Oris Circular muscle surrounding the mouth Lies within the lips Prevents dribbling during chewing  Oral Oesopha Small Large Pharynx Stomach Rectum Anus Cavity gus Intestine Intestine Pharynx Nasal Pharynx has 3 parts: Cavity Nasopharynx So (posterior to nasal cavity ft Pa superior to soft palate) la te Oral Cavity Oropharynx (posterior to _ _ _ _ _ _ _ _ _ _ _ between soft palate and epiglottis) Laryngopharyn x (posterior to larynx, between Epiglottis epiglottis and oesophagus) Larynx Oesophagus Trachea  Oral Oesopha Small Large Pharynx Stomach Rectum Anus Cavity gus Intestine Intestine LO 8 Pulmonary Aspiration Oropharynx and part of laryngopharynx used in both pathways Respiratory tract pathway Risk of aspirating material into respiratory tract Gastrointestinal tract pathway Raising of the larynx towards to oesophagus reduces the chance of aspiration Laryngeal inlet (opening into airway) If it does occur, then the cough reflex engages. Epiglottis moves posteriorly aiding closure of laryngeal inlet  Check your understanding Which part of the pharynx is seen here? Label the structures indicated by an arrow. Grant’s Check your understanding Which of the following muscles are included in the group of muscles of mastication? buccinator lateral pterygoid masseter medial pterygoid orbicularis oris temporalis  Check your understanding Which anatomical structure separates the nasopharynx from the oropharynx? Which anatomical structure separates the oropharynx from the layngopharynx? Grant’s Well done! You should now have a good understanding of the oral cavity and pharynx, which you will study again in greater detail later in the course. Now move on to ‘Gastrointestinal system 2’!