27.31
Small Intestine
The small intestine is a tubular structure extending from the pyloric sphincter of the stomach to the ileocecal valve of the large intestine.
This long, tubular structure has internal circular folds, giving it an enormous surface area. For this reason, the small intestine is the main organ responsible for digestion and absorption in the body.
Anatomically, it is divided into three parts — the duodenum, jejunum, and ileum.
The duodenum is the closest segment to the stomach, wrapped in a C-shape around the pancreas.
This is where chyme mixes with the digestive secretions from the pancreas and liver.
The jejunum follows the duodenum and leads to the ileum. The majority of chemical digestion and nutrient absorption takes place in the jejunum.
The ileum is the last and longest part of the small intestine, connecting to the large intestine at the ileocecal valve.
Both the jejunum and ileum, encircled by the large intestine, are located in the central and lower abdomen. They are suspended by a fan-shaped mesentery from the posterior abdominal wall.
The small intestine is primarily responsible for digestion and nutrient absorption. It spans from the pyloric sphincter to the ileocecal valve and connects to the large intestine.
The small intestine is divided into three main sections - the duodenum, jejunum, and ileum. The duodenum, approximately 25 cm long, is nearest the stomach. It acts as a 'mixing bowl,' where chyme (partially digested food) blends with digestive enzymes from the pancreas and liver. The duodenum's unique C-shape wraps around the pancreas.
The jejunum follows the duodenum. It is roughly 2.5 m long and leads to the ileum, which measures about 3.6 m. The ileum joins the large intestine at the ileocecal valve, marking the end of the small intestine.
The jejunum and ileum are found in the central and lower regions of the abdominal cavity. A fan-shaped mesentery extends from the posterior abdominal wall and supports and gives them mobility. The small intestine's complex design and structure facilitate effective digestion and absorption.
The small intestine is a tubular structure extending from the pyloric sphincter of the stomach to the ileocecal valve of the large intestine.
This long, tubular structure has internal circular folds, giving it an enormous surface area. For this reason, the small intestine is the main organ responsible for digestion and absorption in the body.
Anatomically, it is divided into three parts — the duodenum, jejunum, and ileum.
The duodenum is the closest segment to the stomach, wrapped in a C-shape around the pancreas.
This is where chyme mixes with the digestive secretions from the pancreas and liver.
The jejunum follows the duodenum and leads to the ileum. The majority of chemical digestion and nutrient absorption takes place in the jejunum.
The ileum is the last and longest part of the small intestine, connecting to the large intestine at the ileocecal valve.
Both the jejunum and ileum, encircled by the large intestine, are located in the central and lower abdomen. They are suspended by a fan-shaped mesentery from the posterior abdominal wall.
From Chapter 27:
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27.31 : Small Intestine
Digestive System
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27.1 : Major Organs of the Digestive System
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27.2 : Peritoneum
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27.3 : Histology of the Gastrointestinal (GI) Tract
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27.4 : Nerve Supply of the GI Tract
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27.5 : Regulation of the Digestive System
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27.6 : Blood Supply to the Digestive System
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27.7 : Oral Cavity
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27.8 : Tongue
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27.9 : Salivary Glands and Saliva
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27.10 : Teeth
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27.11 : Tooth Anatomy
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27.12 : Esophagus
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27.13 : Deglutition
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27.14 : Gross Anatomy of the Stomach
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