Small Intestine Diagram with Detailed Explanations

The small intestine diagram shows the anatomy of this important organ helping in nutrient digestion and absorption. It has three sections: duodenum, jejunum, and ileum. A diagram helps explain how enzymes break down food and how to take in nutrients into blood. This is a topic from the Class 11 chapters on Digestion and Absorption which is important for exams such as NEET and AIIMS BSc Nursing, where biology is the major subject.

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This Story also Contains

1. Small Intestine
2. Small Intestine Diagram
3. Parts of the Small Intestine
4. Layers of Small Intestine Diagram
5. Intestinal Glands
6. Video Recommended on Small Intestine

Small Intestine

The small intestine is the main component of the digestive system, which absorbs almost all nutrients. It has three parts: duodenum, jejunum, and ileum. The small intestine breaks down food into nutrients with the help of digestive enzymes and absorbs those nutrients into the bloodstream. Such absorption ensures that the body receives the energy and necessary nutrients, hence being highly important.

Small Intestine Diagram

The diagram showing the parts of the small intestine is given below:

The small intestine represents an important part of the digestive system through which food is received from the stomach and then digested and absorbed. It is a long, coiled tube that starts from the stomach, ends by the large intestine, and extends to a length of about 20 feet. Its long length and structure specialisation let it efficiently process and absorb the needed nutrition for the body's functions.

The small intestine lies in the abdominal cavity, and upon further division, it includes the duodenum, jejunum, and ileum. Various parts of each segment have different roles in digestion, breaking down food, and absorbing it into the bloodstream for utilisation.

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Parts of the Small Intestine

The small intestine is mainly divided into three parts:

Duodenum

• The first part.

• Here most of the chemical digestion is done.

Jejunum

• The middle part.

• Mainly responsible for the absorption of nutrients.

Ileum

• The last part.

• Responsible for absorption of vitamin B12 and salts of bile.

Layers of Small Intestine Diagram

The diagram below shows the different layers of the small intestine.

The layers of the small intestine are divided into:

Mucosa

• The innermost layer, lined with villi and microvilli

• It can increase the surface area for absorption.

Submucosa

• A supportive layer containing blood vessels, nerves and glands.

Muscularis externa

• Responsible for movements of peristalsis and segmentation.

Serosa

• Outermost protective layer.

Diagram of Intestinal villi

Surface Area and Villi

• Villi and microvilli greatly increase surface area to promote nutrient absorption.

• Blood vessels and lymphatics are found in these structures to transport the absorbed nutrients.

Intestinal Glands

Intestinal glands are located on the inner lining of the small intestine and are responsible for digestion. They secrete digestive enzymes, mucus, and hormones. These glands are composed of different cells including goblet cells that produce mucus, enterocytes which are involved in nutrient absorption, and enteroendocrine cells that release hormones to regulate digestion. The secretions help protect the intestine and ensure efficient digestive processes.

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Video Recommended on Small Intestine