The digestive system’s job is to break down the foods we eat, release their nutrients, and absorb them into our bodies. Although the small intestine is the system’s workhorse, performing the majority of digestion and absorbing the majority of released nutrients into the blood or lymph, each of the digestive system organs plays an important role in the process.

1. Small Intestine – The small intestine has a mucosa with simple columnar epithelium, submucosa, smooth muscle with inner circular and outer longitudinal layers, and serosa, similar to the rest of the digestive tract. In terms of function, the small intestine is primarily responsible for nutritional digestion and absorption. Through the hepatopancreatic duct, it receives pancreatic secretions and bile, which help it perform its tasks.
2. Pancreas – Exocrine acini ducts and endocrine islets of Langerhans are two forms of parenchymal tissue found in the pancreas. The pancreas has two primary functions: exocrine and endocrine. Exocrine function: produces chemicals (enzymes) that aid digesting. Endocrine function: releases hormones that regulate the quantity of sugar in your blood.
3. Duodenum – The duodenum is a crucial organ in the digestive system, as it is the first and shortest segment of the small intestine. It is roughly 25 to 30 cm long (“twelve fingers’ length”), C-shaped, and positioned in the upper abdomen at the level of L1-L3. The pancreatic head is located in the C loop. It can be separated into four sections: the superior, descending, horizontal, and ascending parts. The mucosa, submucosa, and muscularis of the duodenum are histologically comparable to those of the other hollow organs of the gastrointestinal system. Absorbing enterocytes, mucus-producing goblet cells, and peptide hormone-producing endocrine cells abound throughout the duodenum.