Anatomy of Esophagus for nursing student

It describes the anatomy of esophagus. it includes the parts of esophagus, layers, sphincters , junctions of esophagus, blood supply of esophagus and its functions

1. ANATOMY OF ESOPHAGUS BY: MS. SAILI GAUDE PRINCIPAL SHIVAM COLLEGE OF NURSING , AMIRGADH

2. Introduction A long fibromuscular tube that joins oral cavity to stomach Length- 25cm Diameter- 2cm Location : cervical vertebrae 6 to thoracic vertebrae 11 It actively facilitates the passage of the food into the stomach under nervous regulation

3. Parts

4. CERVICAL ESOPHAGUS The part of esophagus that travels through the neck

5. Thoracic esophagus Which is located in the thorax, more specifically in the mediastinum

6. ABDOMINAL ESOPHAGUS Which travels past the diaphragm into the abdomen reaching the stomach

7. JUNCTIONS Esophagus is connected at either end by other structures, resulting in 2 junctions: 1) Pharyngoesophageal junction 2) Gastroesophageal junction

8. Pharyngoesophageal junction Located posterior to the cricoid cartilage and formed at the union between the pharynx and the esophagus

9. Gastroesophageal junction Located at the meeting point between the esophagus and stomach

10. SPHINCTERS The passage of food through these junctions is regulated by sphincters: bundles of muscle fibers under involuntary 2 SPHINCTERS 1) UPPER ESOPHAGEAL SPHINCTER 2) LOWER ESOPHAGEAL SPHINCTER

11. 1) UPPER ESOPHAGEAL SPHINCTER The pharyngoesophageal junction is surrounded by the upper esophageal sphincter also known as the cricopharyngeus muscle. This muscle is part of the inferior pharyngeal constrictor muscles

12. LOWER ESOPHAGEAL SPHINCTER Gastroeophageal junction is surrounded by the lower esophageal sphincter also known as cardiac sphincter It is referred to as cardiac sphincter because of its location near the heart The primary function of the LES is to keep the acid and food inside the stomach and prevent it from re- entering into the esophagus The LES is a physiological sphincter as it does not have thickened ring of muscles like anatomical sphincters do. Instead they have circular muscle that works by constricting either around or inside of them.

13. LAYERS OF ESOPHAGUS 1) MUCOSA 2) SUBMUCOSA 3) MUSCULARIS EXTERNA 4) ADVENTITIA

14. MUCOSA Made up stratified squamous epithelium containing numerous mucous glands It secretes mucus which helps lubricate food and shield from stomach acid

15. SUBMUCOSA It is a thick loose fibrous layer connecting the mucosa to the muscularis It contains connective tissues and provides blood supply, nerve supply to the mucosa Together the mucosa and submucosa form long longitudinal folds so that a cross section of the esophagus opening would be start shaped.

16. MUSCULARIS Composed of inner layer in which the fibres are circular and an outer layer of longitudinal fibres . The inner circular muscle fibres are arranged in very tight spiral whereas the longitudinal muscle fibres are loose. When divided into 3 parts the : Upper 1/3 rd – striated muscles Middle 1/3 rd – striated and smooth muscles Lower 1/3 rd – smooth muscles

17. ADVENTITIA Outer layer of the esophagus is composed of loose fibrous tissue that connects the esophagus with neighbouring structures

18. ESOPHAGEAL HIATUS It is situated in the muscular part of the diaphragm at the level of the tenth thoracic vertebra and is elliptical in shape It is the hole through which the esophagus passes through the diaphragm

19. Physiology of esophagus The esophagus is involved in the processes of swallowing and peristalsis to move substances from the mouth to the stomach. The swallowing food begins in the mouth and continues with the contraction of skeletal muscles in the pharynx and esophagus. The upper esophageal sphincter dilates to permit the swallowed substance to enter the esophagus From this point, waves of muscle contraction are called as peristalsis Regions of the esophagus closer to the stomach open through the action of the LES to allow food to enter the stomach