Gastrointestinal Tract (GIT) System Anatomy PDF

2 Anas Abu Alrub Jana ‫] ﺑﺴﻢ اﷲ [‬  Deciduous Teeth Also called primary, baby, or milk teeth They are 20 in number: 4 incisors, 2 canines, and 4 molars in each jaw. Begin to appear at about 6 months of age. Most children hav...

2 Anas Abu Alrub Jana ‫] ﺑﺴﻢ اﷲ [‬  Deciduous Teeth Also called primary, baby, or milk teeth They are 20 in number: 4 incisors, 2 canines, and 4 molars in each jaw. Begin to appear at about 6 months of age. Most children have a complete primary dentition by 3 years of age. They are replaced by the permanent teeth (6-12 years). Permanent Teeth They are 32 in number: 4 incisors, 2 canines, 4 premolars, and 6 molars in each jaw. Starts to appear at about 6 years of age. Most permanent teeth have erupted by 12 years of age. ‫ ﻃﺎﺣﻮﻧﺔ اﻟﻌﻘﻞ‬Third molars (wisdom teeth) are the exception; often do not appear until late teens or early 20s. Permanent Teeth Alveolar process function: to stabilize the teeth inside the The Gingiva (Gums) sockets of the alveolar process It is composed of fibrous tissue covered with mucous membrane. It is firmly attached to the alveolar processes of the jaws and the necks of the teeth. The Salivary Glands Produces saliva to lubricate the oral cavity and aids in the breakdown of food. Contains enzymes (like amylase) help in digestion They are composed of 6 major glands, in addition to minor glands. Major:  2 parotid glands.  2 submandibular glands.  2 Sublingual glands. Minor: 800-1000 minor salivary glands Minor Salivary Glands Mucosa consists of epithelium lining Beneath it is the submucosa They are distributed throughout oral submucosa, in the lips, cheeks, palate, floor of mouth & retromolar area. Also appear in oropharynx, larynx & trachea  The Parotid Gland It is the largest salivary gland. It produces serous saliva, a watery solution rich in enzymes. Located in the parotid region, in a deep hollow below the external auditory meatus, behind the ramus of the mandible and in front of sternocleidomastoid muscle. Anatomically, it can be divided into deep and superficial lobes, which are separated by the facial nerve. Parotid duct emerges from the anterior border of the gland and passes over the lateral surface of masseter  It opens in the vestibule of the mouth opposite the upper 2nd molar tooth. Through a buccinator muscle. Facial nerve ‫العصب السابع‬ stylomastoid foramen After the facial nerve passes the parotid gland, it will be divided into: 1. superficial part 2. Deep part Relations of Parotid gland  Structures Passing through the Parotid gland From Superficial to deep: 1. The facial nerve and its five terminal branches. 2. The external carotid artery and its branches (posterior auricular artery, maxillary artery and superficial temporal artery) 3. The retromandibular vein is Artery formed within the gland by the convergence of the superficial temporal and maxillary veins.  Retromandibular vein Clinical Notes Adenolymphoma: Treatment usually involves surgical excision of the tumor and parotid gland, known as a parotidectomy (facial nerve??) Parotitis: Results of an infection, the parotid gland is enclosed in a tough fibrous capsule. This limits swelling of the gland, producing pain. during parotidectomy: The surgeon must know the structures that located around the parotid gland,...... especially facial nerve. any rupture in facial nerve will affect the facial muscle function. The Submandibular Gland It is a mixed mucous and serous in type. It lies partly under cover of the body of the mandible and is made up of a large superficial part and a small deep part, which are continuous with each other around the posterior border of the mylohyoid muscle Superficial part of submandibular gland The Superficial Part The superficial part lies in the digastric triangle ‫مش مهم كثير‬ Relation: nerves ‫ بس مهم نعرف ال‬  Anteriorly: The anterior belly of the digastric  Posteriorly: The stylohyoid, the posterior belly of the digastric, and the parotid gland.  Medially: The mylohyoid, the hyoglossus, and the lingual and hypoglossal nerves.  Laterally: The gland lies in contact with the submandibular fossa in the medial surface of the mandible. The Deep Part Extends forwards as far as the posterior end of the sublingual gland, between mylohyoid (below and laterally), and hyoglossus and styloglossus (medially). It is related above to Lingual nerve, and below to hypoglossal nerve. ‫ مهمات‬Nerves‫الـ‬ The Submandibular (Wharton’s)Duct Is about 5 cm long, emerges from the middle of the medial surface of the deep part of the gland. It runs forwards and between the sublingual gland and the genioglossus. Opens into floor of mouth on the sublingual papilla, which is situated at the side of the frenulum of tongue.  sublingual papilla Clinical Notes...‫مهم‬ Formation of Calculi in Submandibular Duct: more common in submandibular duct than in parotid duct ??. Submandibular Gland Excision: is a common surgical procedure indicated for conditions such as submandibular gland neoplasia or recurrent calculi.  Surgeon must be acutely aware of three principal nerves ??? lie in close proximity to the gland and its duct. 1. Due to the contents of the parotid gland's secretions 2. Pathway of submandibular duct is ascending to the oral cavity, this increase the possibility of deposits in this duct. 3. Pathway of parotid duct is more straight. The Sublingual Gland Is the smallest of the three paired major salivary glands. It is mixed mucous and serous in type (predominately mucous in nature). It is almond-shaped, situated beneath the mucous membrane of the floor of mouth (sublingual fold).  Bordered laterally by the mandible and medially by genioglossus muscle of the tongue.  The glands form a shallow groove on the medial surface of the mandible known as the sublingual fossa. Sublingual ducts: Are 8 - 20 in number, open on the sublingual fold.  Clinical Note Ranula  Is a type of mucocele (mucous cyst) that occurs in the floor of the mouth inferior to the tongue.  It is the most common disorder associated with the sublingual glands due to their higher mucin content in secretions compared to other salivary glands.  Can be caused by trauma to the delicate sublingual gland ducts causing them to rupture. So the mucus accumulates.  Thank you [email protected]  Systemic Module GIT “Anatomy” The Esophagus Dr. Ayman Alzubi Faculty of Medicine, Yarmouk University # Pharynx divided into three parts: Nasopharynx , oropharynx, laryngopharynx ‫ وبتكمل‬larynx ‫مام عال‬-‫ إما بتدخل ل‬laryngopharynx ‫* بعد ال‬ esophagus ‫سفل لل‬-‫* أو بتستمر ل‬ Introduction It is a muscular 25cm long tube, extending from the pharynx to the stomach. ‫ مهم جدا‬EXTENSION:  Begins at the level of lower border of cricoid cartilage (C6).  Descends in front of the vertebral column goes through posterior mediastinum.  Passes through the diaphragm at the level of T10.  Ends at the level of T11 by joining the stomach at the cardiac orifice. Normally it’s kept closed (collapsed) and opens (dilates) only during the passage of the food.  C6 Vertebral Level as a Landmark Superior Constrictor Middle Pharynx Constrictor Cricoid Inferior C6 Larynx cartilage Constrictor Esophagus Trachea At the C6 level, progressing inferiorly:  Larynx ends, and the trachea begins  Pharynx ends, and the esophagus begins  Location of the pharyngoesophageal sphincter and cricoid cartilage  Parts of Esophagus Topographically, there are three distinct regions: 1. Cervical part (4 cm in length).  Extends from the lower border of cricoid cartilage to the superior border of manubrium sterni. 2. Thoracic part (20 cm in length).  Extends from superior border of manubrium sterni to the esophageal opening in the diaphragm. 3. Abdominal part (1-2 cm in length).  Extends the esophageal opening in the diaphragm to the cardiac orifice of the stomach. *Right vagus nerve passes posterior to esophagus. Three parts: *Left vagus nerve passes Anterior to esophagus. Cervical Thoracic Abdominal  Relations of Esophagus In the neck (cervical part) Anteriorly: Trachea, Recurrent laryngeal nerves. Thyroid gland Posteriorly: Prevertebral muscles and the Vertebral column. Laterally: Thyroid gland and Carotid sheath, on the left side Thoracic duct (at C6). Relations of Esophagus In the thorax Anteriorly: Trachea, Recurrent laryngeal nerves, Left bronchus, Left atrium of the heart. Posteriorly: Vertebral column, Thoracic duct, Azygos vein, Right posterior intercostal arteries, Descending thoracic aorta (at the lower end). Laterally: On the Right side: Right mediastinal pleura, Azygos vein. On the left side: Left mediastinal pleura, Left subclavian artery, Aortic arch, Thoracic duct. posterior ‫ بكون‬trachea ‫ بالنسبة لل‬esophagus ‫ لل‬position‫ ال‬ Anterior in the diaphragm ‫ بعدين بصير‬.. Right side ‫ أول شيء بكون عال‬descending aorta ‫ وبالنسبة لل‬ (Left atrium ‫ )لل‬posterior ‫ بيكون‬heart ‫ وبالنسبة لل‬  Relations of Esophagus In the abdomen Anteriorly: Posterior surface of the left lobe of the Liver. Posteriorly: Left crus of the Diaphragm. The left and the right Vagus nerve lie on the anterior and posterior surfaces, respectively.  Esophageal Constrictions First constriction:  at the pharyngoesophageal junction (at C6). Second constriction:  where it’s crossed by the arch of aorta (at T4). Third constriction:  where it’s crossed by the left principal bronchus(at T5-T6). Fourth constriction:  where it pierces the diaphragm (at T10). ‫ ؟‬constrictions ‫ إيش أهمية هاي ال‬ ‫طفال( فاحتمالية انه يعلق‬8‫صا ا‬ً ‫ بينبلع )خصو‬foreign bodies ‫أي‬.‫ أكبر فبقدر أحدد مكانه‬constrictions ‫بهاي ال‬ Three constrictions ‫حفظ مهمات‬ Distances from the upper incisor teeth: (Two sphincters*) : Cervical/Pharyngoesophageal* 6 in. (15 cm) (Upper Esophageal Sphincter) C6 Thoracic Second constriction (left bronchus/ T4 aortic arch) 10 in. (25 cm) Diaphragmatic* (Lower Esophageal Sphincter) T10 16 in. (41 cm)  Clinical Note The anatomical constrictions of esophagus are of considerable clinical importance, because:  These are the sites where swallowed foreign bodies may stuck in the esophagus.  Because a slight delay in the passage of food or fluid occurs at these levels, the burning is the worst and strictures develop here after the drinking of caustic fluids..  These are common sites of carcinoma of the esophagus.  These are sites via which it might be difficult to pass esophagoscope/gastric tube. It is useful to remember that their respective distances from the upper incisor teeth  Esophageal Sphincters There are two sphincters present in the esophagus, known as: 1. The upper esophageal sphincter. 2. The lower esophageal sphincter. They act to prevent the entry of air and the reflux of gastric contents, respectively. The Upper Esophageal Sphincter At the junction between the pharynx and esophagus. It is an ANATOMICAL produced by the cricopharyngeus muscle (striated muscle sphincter). Normally, it is constricted to prevent the entrance of air into the esophagus.  Upper Esophageal Sphincter Inferior Pharyngeal Constrictor Cricopharyngeus Cricoid cartilage Esophagus The Lower Esophageal Sphincter At the gastro-esophageal junction. It is classified as a PHYSIOLOGICAL (or functional) sphincter., composed of an intrinsic and an extrinsic component: Push food Down  INTRINSIC- The peristalsis of esophageal muscle fibers  EXTRINSIC- Diaphragm muscle.Contract During esophageal peristalsis, the sphincter is relaxed to allow food to enter the stomach. Otherwise at rest, the function of this sphincter is to prevent the gastric reflux.  ‫ طلع لل‬stomach ‫جزء من ال‬ Lower Esophageal Sphincter thorax Diaphragmatic Esophagus Clinical Anatomy: Hiatal Hernia can weaken LES constriction function, cause predisposition to gastroesophageal Cardia of reflux disease (GERD). stomach Stratified NB. Notice the normal abrupt mucosal transition from esophagus columnar to stomach (Z- line). Z-line  Blood Supply CERVICAL PART  Inferior thyroid arteries. THORACIC PART  Esophageal branches of descending thoracic aorta, and bronchial arteries.. ABDOMINAL PART  Ascending branches of the left phrenic and left gastric arteries. Venous Drainage Cervical Region: Drains into the inferior thyroid veins (systemic). Accessory Hemiazygos V. Thoracic Region: Hemiazygos V. Drains into the hemiazygos and Azygos azygos veins (systemic). Vein Abdominal Region: Drain mainly to the portal vein (via left gastric v.) Drain also to systemic circulation The lower part of esophagus drains into both the systemic and portal circulation, thus it is the site of portocaval (porto-systemic ) anastomosis ‫ راح‬portal circulation‫تخيل لو الدم رجع عال‬ portal hypertension ‫يصير‬ ‫ في ال‬vein ‫*الدم بيصير يرجع لل‬ ‫ريء‬:‫ فبيصير دوالي ا‬anastomosis  Lymphatics The lymphatics from the proximal 1/3rd  drain into the deep cervical LNs  subsequently into the thoracic duct. Middle 1/3rd  into superior and posterior mediastinal nodes. Distal 1/3rd  gastric and celiac lymph nodes. Innervation of the Esophagus Most of the esophagus (all except for the most proximal part) is under autonomic control mediated by esophageal plexus (peristalsis, arterial vasoconstriction, glandular secretion) Sympathetic supply (General): Spinal segments T1-T10  Sympathetic trunk Contain fibers Parasympathetic supply: Left Vagus Nerve  Esophageal Plexus Right Vagus Nerve  Esophageal Plexus  Clinical Notes Esophageal Varices  They are abnormally dilated sub-mucosal veins due to portal hypertension.  Occurs secondary to chronic liver disease, such as cirrhosis.  The ruptured esophageal varices cause hematemesis (vomiting of blood). Clinical Notes Achalasia  The lower esophageal sphincter fails to relax when the food is swallowed  Consequently food accumulates in the esophagus.  Unknown cause: maybe disorder in the innervation of sphincter.  Dysphagia (difficulty in swallowing) and regurgitation are common symptoms.  Rat tail appearance in barium swallow evaluation.  Clinical Notes Gastroesophageal Reflux Disease (GERD)  The reflux of gastric contents into the lower esophagus  Acid reflux is due to malfunctioning lower esophageal sphincter. ‫ مهم‬ Symptoms include the taste of acid in the back of the mouth, heartburn, bad breath, and chest pain.  ✅ ‫ﰎ ﺑﺤﻤﺪ اﷲ‬ Thank you [email protected]