What is the function of muscles at bottom esophagus?

Function of Muscles at the Bottom Esophagus:

The bottom or lower part of the esophagus, known as the gastroesophageal junction (GEJ), contains several muscles responsible for various functions related to swallowing, digestion, and preventing the backflow of stomach contents. These muscles work in coordination to ensure the proper passage of food and fluids into the stomach while maintaining a barrier against acid reflux and regurgitation.

1. Lower Esophageal Sphincter (LES):

- The most important muscle at the bottom esophagus is the lower esophageal sphincter (LES). It acts as a circular valve located at the junction between the esophagus and the stomach.

- The LES remains tightly closed under normal conditions to prevent the reflux of stomach acid into the esophagus.

- During swallowing, the LES relaxes, allowing food and liquid to pass through into the stomach.

- Its proper functioning is crucial for preventing acid reflux and heartburn.

2. Crural Diaphragm:

- The crural diaphragm consists of muscle fibers that wrap around the lower esophagus and contribute to the LES function.

- It helps to support and maintain the position of the LES within the diaphragm.

- When functioning normally, the crural diaphragm provides additional pressure to keep the LES closed.

3. Esophageal Longitudinal Muscles:

- The esophageal longitudinal muscles are long muscle fibers that run along the entire length of the esophagus, including the bottom portion.

- These muscles help in creating a coordinated wave-like motion called peristalsis.

- Peristalsis propels food and fluids from the upper part of the esophagus down towards the stomach.

4. Oblique Esophageal Muscles:

- The oblique esophageal muscles are found in the lower esophagus and form a network of fibers that run diagonally between the longitudinal muscle layers.

- They assist in maintaining the shape and tone of the esophagus while facilitating the passage of swallowed material.

5. Mucosal Muscle Layer:

- The mucosal muscle layer is a thin layer of muscles located just beneath the inner lining (mucosa) of the esophagus, including the bottom portion.

- These muscles help in fine-tuning the movements and secretions within the esophagus.

Overall, the coordinated actions of these muscles at the bottom esophagus ensure the efficient passage of food and liquids into the stomach, prevent acid reflux, and maintain the proper physiological environment for digestion.