HISTOLOGY OF ESOPHAGUS &gastro esophageal junction By Dr. Sobia Ibrahim Assistant Professor Anatomy, KEMU

ESOPHAGUS Is muscular tube Extends from pharynx to stomach Wall has four layers: Mucosa Epithelium Lamina propria Muscularis interna or muscularis mucosae Submucosa Muscularis externa Adventitia / Serosa

UPPER 1/3 OF ESOPHAGUS MUCOSA SUB-MUCOSA MUSCULARIS EXTERNA ADVENTITIA Epithelium: Stratified squamous non-keratinized Lamina propria: scattered lymphocytes, few lymphatic nodules, mucous glands, blood vessels Muscularis mucosae: Thick, smooth muscles longitudinally arranged SUB-MUCOSA Collagen & elastic fibres, mucous glands, blood vessels, nerves MUSCULARIS EXTERNA Skeletal (striated) muscles ADVENTITIA Collagen & elastic fibers, blood vessels

MIDDLE 1/3 OF ESOPHAGUS MUCOSA Epithelium: stratified squamos non- keratinized Lamina propria: : scattered lymphocytes, few lymphatic nodules, mucous glands, blood vessels Muscularis mucosae: thick, smooth muscles longitudinally arranged SUB-MUCOSA Collagen & elastic fibres, mucous glands, blood vessels, nerves MUSCULARIS EXTERNA Skeletal (striated) muscles, Smooth muscles ADVENTITIA Collagen & elastic fibers, blood & lymphatic vessels

LOWER 1/3 OF ESOPHAGUS MUCOSA Epithelium: Simple columnar Lamina propria: scattered lymphocytes, few lymphatic nodules, mucous glands, blood vessels Muscularis mucosae: thick, smooth muscles longitudinally arranged SUB-MUCOSA Collagen & elastic fibres, mucous glands, blood vessels, nerves MUSCULARIS EXTERNA Smooth muscles ADVENTITIA/ SEROSA Collagen & elastic fibers, blood & lymphatic vessels

GASTROESOPHAGEAL REFLUX DISEASE It is associated with incompetent barriers at this junction; caused by hiatal hernia, decrease in lower esophageal sphincter tone. Results in reflux esophagitis as mucosal barriers are not sufficient to protect esophagus from acids, pepsin & bile causing heart burns/atypical chest pain

BARRETT’S ESOPHAGUS Reflux of gastric contents throu lower esophageal sphincter Gastric acid in esophagus Heart burn With time, metaplasia of epithelium (protective) Barrett’s esophagus High risk for carcinoma

STOMACH PARTS OF STOMACH Rugae Three histological zones Cardia Fundus Body Pylorus Rugae Three histological zones

CARDIOESOPHAGEAL JUNCTION

Esophageal cardiac junction

MUCOSA: 1:Epithelium changes from: Startified squamous non keratinised into simple columnar. 2: Lamina propria: esophageal cardiac glands but in stomach (cardiac, fundic and pyloric glands). They are tubular and deep. 3:Muscularis mucosae: thick longitudinal in esophagus but thin and two layered in stomach. Submucosa: esophageal glands proper disappear. No glands in submucosa of stomach. Muscularis externa: three layered in stomach an additional oblique layer is there

GASTROESOPHAGEAL REFLUX DISEASE It is associated with incompetent barriers at this junction; caused by hiatal hernia, decrease in lower esophageal sphincter tone. Results in reflux esophagitis as mucosal barriers are not sufficient to protect esophagus from acids, pepsin & bile causing heart burns/atypical chest pain