Difference Between Muscularis Layer of Esophagus and Stomach

The key difference between muscularis layer of esophagus and stomach is that muscularis layer of the esophagus has two layers while muscularis layer of the stomach has three layers.

Gastrointestinal tract or GI tract has four layers. They are mucosa, submucosa, muscularis and serosa. Each layer is composed of different tissues. They also fulfill different functions. Mucosa is the innermost layer and helps in absorption and secretion. Submucosa is a highly vascularized, dense irregular layer of connective tissue, and it supports mucosa. Muscularis layer is the adventitia; layers of connective tissue that is responsible for the segmental contractions and peristaltic movements in the GI tract. Serosa is made up of a thin connective tissue layer and a secretory epithelial layer. Secretory epithelium secretes a serous fluid which provides lubrication to reduce friction.

CONTENTS

1. Overview and Key Difference
2. What is Muscularis Layer of Esophagus 
3. What is Muscularis Layer of Stomach
4. Similarities Between Muscularis Layer of Esophagus and Stomach
5. Side by Side Comparison – Muscularis Layer of Esophagus vs Stomach in Tabular Form
6. Summary

What is Muscularis Layer of Esophagus?

Muscularis layer of esophagus is one of the four layers that make the esophagus wall. It is composed of two smooth muscle layers: longitudinal outer muscular layer and inner circular layer. However, in the upper esophagus, a part of the muscularis layer is composed of skeletal muscle rather than smooth muscle.

Muscularis layer facilitates the contractions and peristaltic movements. Therefore, food moves down through the esophagus due to the peristaltic movements shown by muscularis layer of esophagus.

What is Muscularis Layer of Stomach?

Muscularis layer of stomach is the third layer of the stomach wall located deep in the submucosa. It is responsible for the segmental contractions and peristaltic movements in the GI tract.

Generally, muscularis layer has two layers. These layers are the inner circular layer and a longitudinal outer muscular layer. But unlike other parts of the GI tract, muscularis layer of stomach has a third layer called the inner oblique layer. This layer helps to churn the chime in the stomach. Circular muscle layer prevents food from traveling backwards. The longitudinal layer shortens the GI tract. Peristalsis is a result of contraction of these three layers. Therefore, muscularis layer produces churning movements required for mechanical digestion.

What are the Similarities Between Muscularis Layer of Esophagus and Stomach?

• Muscularis layer of esophagus and stomach are parts of the GI tract.
• Both layers are composed of smooth muscles.
• Muscularis layers are responsible for segmental contractions and peristalsis movements.

What is the Difference Between Muscularis Layer of Esophagus and Stomach?

Muscularis layer of esophagus is one of the tissue layers composed of two smooth muscular layers. Muscularis layer of stomach is one of the four tissue layers composed of three smooth muscle layers. Therefore, muscularis layer of esophagus has two layers while muscularis layer of stomach has three layers. Therefore, this is the key difference between muscularis layer of esophagus and stomach. Moreover, a part of the muscular layer of upper esophagus is skeletal muscle rather than the smooth muscle. Muscularis layer of the stomach, on the other hand, does not have skeletal muscle.

Below infographic tabulates more differences between muscularis layer of esophagus and stomach.

Summary – Muscularis Layer of Esophagus vs Stomach

Muscularis externa is the third layer out of the four tissue layers that compose the GI tract. It is responsible for segmental contractions and peristaltic movements in the GI tract. The thickness of muscularis layer in the esophagus and stomach (two parts of the GI tract) varies. There are two layers in the muscularis layer of the esophagus. But there are three layers in the muscularis layer of the stomach. Therefore, muscularis layer of esophagus has two smooth muscle layers – longitudinal and circular – while the muscularis layer of stomach has three smooth muscle layers – longitudinal, circular and oblique. Thus, this is the key difference between muscularis layer of esophagus and stomach.

Reference:

1. “Layers of the Alimentary Canal.” Lumen, Available here.
2. Pirie, Egle. “Stomach Histology.” Kenhub, Kenhub, 29 Oct. 2020, Available here.

Image Courtesy:

1. “2412 The Esophagus” By OpenStax College – Anatomy & Physiology, Connexions Web site, Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia
2. “2415 Histology of StomachN” By OpenStax College – Anatomy & Physiology, Connexions Web site, Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia