Oesophagus digestive system.pptx micro teaching

Introduction

The oesophagus (also spelled esophagus) is a vital part of the human digestive system, serving as a muscular conduit for the transport of food and liquids from the pharynx to the stomach. Though often described simply as a “food pipe,” its anatomy and physiology are complex and precisely regulated to facilitate safe and efficient swallowing.

The oesophagus not only functions as a passive tube but also actively participates in peristaltic movement, sphincter regulation, and protection against reflux and mechanical damage. Understanding its structure and function is essential for comprehending normal digestion and diagnosing related disorders such as gastroesophageal reflux disease (GERD), achalasia, and esophageal cancer.


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Anatomical Overview

1. Location and Extent

The oesophagus is a muscular tube approximately 25 cm (10 inches) long in adults.

It extends from the lower border of the cricoid cartilage (C6 vertebral level) to the cardiac orifice of the stomach (T11 vertebral level).

It passes through three anatomical regions:

1. Cervical part – from C6 to the thoracic inlet (about 4–5 cm long).


2. Thoracic part – from thoracic inlet to the diaphragm (about 18–20 cm long).


3. Abdominal part – from the diaphragm to the stomach (about 1–2 cm long).





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2. Anatomical Relations

a. Cervical oesophagus

Anterior: Trachea

Posterior: Prevertebral fascia and vertebral column

Lateral: Lobes of the thyroid gland, recurrent laryngeal nerves, and carotid sheaths


b. Thoracic oesophagus

Anterior: Trachea (upper part), left atrium, and pericardium

Posterior: Thoracic vertebral bodies, thoracic duct, and descending aorta

Lateral: Right pleura, azygos vein (right), thoracic aorta (left), and vagus nerves


c. Abdominal oesophagus

Anterior: Left lobe of the liver

Posterior: Left crus of the diaphragm



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3. Constrictions of the Oesophagus

The oesophagus has four physiological constrictions where its lumen is narrower:

1. Upper oesophageal sphincter (UES) – at the cricoid cartilage (C6 level)


2. Aortic arch constriction – at T4 level


3. Left main bronchus constriction – at T5 level


4. Diaphragmatic constriction – at T10 level (oesophageal hiatus)



These constrictions are clinically important during endoscopy, nasogastric tube insertion, or ingestion of caustic substances.


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4. Oesophageal Sphincters

The oesophagus has two major sphincters:

a. Upper Oesophageal Sphincter (UES)

Formed mainly by the cricopharyngeus muscle and the inferior pharyngeal constrictor.

Function: Prevents air from entering the oesophagus during breathing and prevents reflux into the pharynx.


b. Lower Oesophageal Sphincter (LES)

A physiological sphincter located at the junction with the stomach (gastroesophageal junction).

Formed by: Circular smooth muscle thickening, the diaphragmatic crura, and an oblique angle (angle of His) at the gastric cardia.

Function: Prevents gastric contents from refluxing into the oesophagus.

1. Oesophagus MR.PRANAJIT

2. Introduction The oesophagus is a narrow part of the alimentary canal. Its start from lower end of pharynx to cardiac orifice of stomach. Oesophagus also known as GULLET. IT is about 25cm long . Oesophagus is a muscular tube which connected to stomach. The place where oesophagus connected to stomach called GASTROESOPHAGIAL Junction.

3. Dimension and location DIMENSTION Lenth is 25 cm Diameter is 1.5 cm LOCATION It is lies in the median plane of the thorax. Anterior part of the vertebral Colum . Posterior part of the trachea.

4. Parts of oesophagus Cervical Thoracic Abdominal

5. Sphincter of oesophagus Two sphincter are present in oesophagus Upper and lower oesophageal sphincter Upper oesophageal sphincter :- Also known as cricopharyngeal sphincter. Its starting part of oesophagus after pharynx. Its prevents air passing into the oesophagus during inspiration. Upper oesophageal sphincter:- Also known as cardiac sphincter. Its an end part of oesophagus which connected to stomach. Its prevents the back flow of gastric acid food particles from stomach to oesophagus.

6. Structure of oesophagus Outer layer - also called Adventitia which help oesophagus to attach near by body parts. Muscular layer – made-up of circular muscles fibres , helps to pushes food in to the stomach. Submucosa - have mucosal glands which produce mucus which keeps the oesophagus moist. Mucosa – inner layer of the oesophagus. This smooth layer helps food to pass smoothly in to the stomach.

7. Function of oesophagus HOME WORK

8. Blood supply Arteries: oesophagus is get blood supply by the branches of descending thoracic aorta and branches of left gastric artery. Veins : left gastric vein.

9. Structure This Photo by Unknown Author is licensed under CC BY This Photo by Unknown Author is licensed under CC BY-SA-NC

10. Structure of oesophagus