Esophagus Lecture Notes PDF

Anatomy II– MED201  The Basics  Digestive system is the system responsible for digestion Digestive track Accessory glands  The Basics Digestive track Accessory glands Salivary glands Oral c...

Anatomy II– MED201  The Basics  Digestive system is the system responsible for digestion Digestive track Accessory glands  The Basics Digestive track Accessory glands Salivary glands Oral cavity Liver Pharynx Esophagus Pancreas Stomach + Small intestine Spleen Large intestine Colon Anus  The Basics Digestive track  Passage of food  Digestion  Absorption  Defecation  Endocrine functions  Immunological functions  The Basics Accessory glands  Production of chymes necessary for digestion  Salivary glands  Saliva  Liver  Bile  Pancreas  Pancreatic juice  Hormonal roles  Immunological roles  Other roles Oral cavity Vestibule: area between the teeth, lips and cheeks Oral cavity proper: alveolar process (containing the teeth) and at the back by the isthmus of the fauces  Roof of oral cavity Hard palate  Palatine process of maxilla  Palatine bones Soft palate  Complex of muscles  Uvula  The teeth Incisor teeth Canine teeth Premolar teeth Molar teeth The tongue Intrinsic muscles  The tongue Palatoglossius Styloglossius Genioglossius Hyoglossius  Salivary glands  Parotid: Drains through buccinators, relationship with facial nerve  Submandibular: Drains at floor of mouth, relationship with lingual a.  Sublingual: Drains at floor of the mouth  Esophagus Definition  Fibromuscular tube extending from pharynx to stomach  18-25 cm long Function  Passage of food from mouth to stomach in a coordinated manner  No digestive functions Extent  From pharynx (cricoid cartilage)  To gastroesophageal junction (stomach)  Esophagus Borders Cricoid cartilage C5 Thoracic inlet Cervical esophagus Thoracic esophagus Diaphgragm T11-12 Abdominal esophagus Esophagus Superior border Esophagus Cervical part Left Right innominate v. innominate v. Innominate a. Left common carotid Left subclavian a.  Cervical esophagus Relationships Posterior  Cervical spine Anterior  Trachea Lateral  Carotid a.  Vagus n.  Thyroid  Recurrent laryngeal nerve  Cervical esophagus Relationships Posterior Trachea  Cervical spine Thyroid Gland Anterior  Trachea Lateral  Cervical neurovascular bundle Vertebra  Thyroid  Recurrent laryngeal nerve Carotid sheath (common carotid a, jugular v, vagus n, lymph nodes)  Thoracic esophagus Relationships Posterior  Thoracic spine  Aorta (half inferior) Anterior  Trachea & bifurcation  Left bronchus  Pericardium Lateral  Aorta (half superior)  Azygos vein  Thoracic duct  Vagus nerves Thoracic esophagus Relationships  Esophagus Abdominal esophagus Surrounding structures: Anteriorly - Peritoneum - Left vagus n. Posteriorly - Descending aorta - Right vagus n.  between thoracic and abdominal part esophagus passes through the esophageal hiatus of the diaphragm  Esophagus Abdominal esophagus  Esophagus Inferior border  the cardia of the stomach cardial  gastro-esophageal junction notch  at the level of 11th thoracic vertebrae  Esophagus Inferior border Inferior border z-line abrupt mucosal transition:  non-keratinized stratified squamous epithelium of the esophagus  simple columnar epithelium of the stomach  Esophagogastric junction Points of view Gastroenterology Histology Anatomy  Esophagogastric junction Functional anatomy Purpose:  Maintenance of gastric fluid inside the stomach and prevention of reflux at the esophagus. Elements:  Lower esophageal sphincter  Crura of the diaphgragm  Angle of Hiss  Intrabdominal pressure  Esophagus Curvatures 2 anteroposterior curvatures correspond to curvatures of the cervical and thoracic vertebral column 2 curves in the coronal plane The 1st at the upper part of the esophagus inclines to the left and returns to the midline at the level of T5 The 2nd curve to the left formed as the esophagus bends to cross the descending thoracic aorta. Esophagus Curvatures  Esophagus Constrictions Cervical constriction (15 cm)  Pharyngoesophageal junction  Upper esophageal sphincter  By cricopharyngeous muscle Thoracic constriction (25 cm)  Crossing of aortic arch and left bronchus Diaphragmatic constriction (40 cm)  Esophageal hiatus of diaphragm  Esophagus Sphincters Sphincters (functional, but not anatomical) upper esophageal sphincter  inferior pharyngeal constrictor  skeletal muscle, but is not under conscious control  opening by the swallowing reflex lower esophageal sphincter  gastroesophageal or cardioesophageal sphincter  prevents gastroesophageal reflux  Esophagus Arterial vascularization  Esophagus receives arterial vascularization from thoracic aorta branches  Venous drainage parallels arterial vascularization  Esophagus Lymphatic drainage  Lymphatic drainage of the esophagus is rich  It can occur throughout all its course from neck to abdomen  Esophagus Lymphatic drainage  Lymph from below brachial bifurcation tends to travel to the abdomen  Lymph from above tracheal bifurcation tend to travel to the neck  Esophagus Innervation  Sympahetic: Thoracic chain  Parasympathetic: Vagus nerves The two vagus nerves give branches in front of the esophagus and form the esophageal plexus After that left vagus nerves assumes an anterior position and becomes anterior vagal trunk while the right assumes a posterior position becomes posterior vagal trunk Questions?