Layers of Intestinal Wall

Layers of Intestinal Wall

• The intestinal wall consists of four layers: mucosa, submukosa, muscularis, and serosa.
• Each layer has a specific function and structure.

Mucosa

• The mucosa is the innermost layer of the intestinal wall.
• It consists of absorptive cells, goblet cells, intestinal glands, and enteroendocrine cells.
• The mucosa is rich in MALT (mucosa-associated lymphoid tissue).
• It is responsible for absorption, digestion, and secretion.

Submukosa

• The submukosa is the layer beneath the mucosa.
• It contains Duodenal glands that secrete alkaline mucus.
• It is composed of loose connective tissue, lymphatic vessels, and blood vessels.

Muscularis

• The muscularis is the layer of smooth muscle that surrounds the intestinal wall.
• It is responsible for peristaltic movements that propel food through the digestive system.
• It has two layers: an inner circular layer and an outer longitudinal layer.

Serosa

• The serosa is the outermost layer of the intestinal wall.
• It is a thin layer of connective tissue that surrounds the intestine.
• It is also known as the visceral peritoneum.
• It is continuous with the peritoneum of the abdominopelvic cavity.

Inervation of Intestine

• The intestine has two types of innervation: enteric nervous system (ENS) and autonomic nervous system (ANS).
• The ENS is the intrinsic nervous system of the gut and consists of two plexuses: myenteric plexus and submucosal plexus.
• The ANS is the extrinsic nervous system that controls the intestine and consists of parasympathetic and sympathetic nerves.

Esophagus

• The esophagus is a muscular tube that propels food into the stomach.
• It has a mucosa, submukosa, and muscularis layers.
• The mucosa is lined with stratified epithelium and has a lamina propria with blood vessels and lymphatic nodules.
• The muscularis is composed of skeletal muscle in the upper third and smooth muscle in the lower two-thirds.

Stomach

• The stomach is a sac-like organ that secretes digestive enzymes and acid.
• It has a mucosa, submukosa, and muscularis layers.
• The mucosa has rugae, gastric pits, and glands that produce pepsinogen, renin, and lipase.
• The stomach has a capacity of around 1500 ml and produces chyme.

Small Intestine

• The small intestine is the longest part of the intestine and is responsible for digestion and absorption.
• It has a mucosa, submukosa, and muscularis layers.
• The mucosa has villi and microvilli that increase the surface area for absorption.
• The small intestine has three regions: duodenum, jejunum, and ileum.

Explore the structure and function of the four layers of the intestinal wall: mucosa, submucosa, muscularis, and serosa.