A diagram of small intestine shows its structure consisting of the duodenum, jejunum, and ileum. The small intestine is a long, coiled tube that runs from the stomach’s pyloric sphincter to the ileocecal valve, which joins it to the large intestine. The diagram of small intestine class 10 is an important topic in the biology syllabus. In this article, we will read about the structure with the help of a diagram of small intestine.
The diagram of small intestine with the label is given below:
Diagram of Small Intestine
Table of Content
What is Small Intestine?
In vertebrates, such as humans, the small intestine plays a vital role in the digestive system. The large intestine and stomach are separated by this lengthy, coiled tube. Despite its name, the small intestine has a smaller diameter than the large intestine. Nutritional absorption and digestion from food is its main function. When food is broken down into its constituent parts, it helps the body to absorb these nutrients into circulation, where they are subsequently sent to the body’s cells for growth, repair, and energy.
Also Read: Human Digestive System – Parts, Organ, Diagram & their Functions
Small Intestine Structure
The structure and function of small intestine is discussed in brief below:
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Duodenum
- Location: Begins at the stomach’s pyloric sphincter.
- Structure: Approximately 25–30 cm long with a C-shaped bend around the pancreatic head.
- Function: Receives partially digested food (chyme) from the stomach, mixes it with bile and pancreatic enzymes for further digestion.
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Jejunum
- Location: Middle section of the small intestine, after the duodenum.
- Structure: About 2.5 meters long with larger diameter and thicker walls.
- Function: Main site for absorption of nutrients, especially proteins and carbohydrates.
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Ileum
- Location: Connects to the large intestine via the ileocecal valve.
- Structure: Longest part, approximately 3.5 meters long, with smaller diameter and thinner walls compared to jejunum.
- Function: Absorbs lipids, fat-soluble vitamins, bile salts, and vitamin B12, and facilitates passage of undigested material to large intestine.
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Villi
- Finger-like projections on the inner lining of the small intestine.
- Increase surface area for nutrient absorption, contain blood vessels and lacteals.
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Microvilli
- Surface-based epithelial cells lining the villi.
- Further increase surface area for nutrient absorption, contain enzymes aiding in digestion.
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Blood Supply and Lymphatics
- Supplied by branches of superior mesenteric artery.
- Veins drain blood into superior mesenteric vein, then to liver via hepatic portal vein.
- Lymphatic vessels (lacteals) collect absorbed lipids and fat-soluble vitamins, drain into lymphatic veins for transport to thoracic duct or right lymphatic duct.
Conclusion-Diagram of Small Intestine
In summary, the small intestine is an important organ in the digestive system that is crucial for the absorption of nutrients that are needed to keep the body functioning. The diagram of small intestine shows the structure consisting of duodenum, jejunum, and ileum—the three main segments. They help in the breakdown of food, assimilation of nutrients, and movement of those nutrients throughout the body. Villi and microvilli significantly expand the surface area that may be absorbed, and the complex system of lymphatics and blood arteries guarantees the passage of nutrients, oxygen, and waste products out of the body.
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FAQs on Diagram of Small Intestine
What is the Structure of the Small Intestine?
The small intestine is a long, coiled tube lined with finger-like projections called villi, made up of duodenum, jejunum and ileum which greatly increase its surface area for nutrient absorption.
What are the Three Parts of the Small Intestine?
The three parts of the small intestine are the duodenum, jejunum, and ileum, each with distinct structural characteristics and functions in digestion and nutrient absorption.
What is the Secretion of the Small Intestine Class 10?
The small intestine secretes digestive enzymes, such as lactase, sucrase, and maltase, to break down carbohydrates, as well as peptidases and lipases to digest proteins and fats, respectively, facilitating nutrient absorption.
What is the Length of the Small Intestine Class 10?
The small intestine typically measures about 6-7 meters (20-23 feet) in length in adults, providing ample surface area for nutrient absorption and digestion of food.
What is Small Intestine Function?
The small intestine functions primarily in the digestion and absorption of nutrients from food, including carbohydrates, proteins, fats, vitamins, and minerals.
What is Villi?
Villi are tiny finger-like projections lining the inner surface of the small intestine, increasing its surface area for efficient absorption of nutrients from digested food into the bloodstream.
What is the Function of Jejunum?
The jejunum primarily functions in the absorption of nutrients, particularly carbohydrates, proteins, and some vitamins, due to its extensive surface area provided by villi and microvilli, facilitating efficient nutrient uptake into the bloodstream for energy and bodily functions.