Explain about the small intestine, ileum, and jejunum.

The small intestine is a long, coiled tube that is part of the digestive system. It is located between the stomach and the large intestine and is responsible for the majority of nutrient absorption in the body. The small intestine is divided into three sections: the duodenum, the jejunum, and the ileum.

The jejunum is the middle section of the small intestine, located between the duodenum and the ileum. It is approximately 2.5 meters long and is responsible for the majority of nutrient absorption in the small intestine. The jejunum has a larger diameter and thicker walls compared to the ileum, which allows for more efficient absorption of nutrients.

The ileum is the final section of the small intestine, located between the jejunum and the large intestine. It is approximately 3.5 meters long and is responsible for the absorption of bile salts, vitamin B12, and any remaining nutrients that were not absorbed in the jejunum. The ileum also plays a role in the immune system, as it contains specialized cells that help protect the body from harmful bacteria and other pathogens.

Overall, the small intestine, ileum, and jejunum play crucial roles in the digestion and absorption of nutrients in the body, helping to provide the body with the energy and nutrients it needs to function properly.

Small Intestine

The small intestine is a long, coiled tube responsible for absorbing most of the nutrients from food. It is divided into three sections: the duodenum, jejunum, and ileum.

Jejunum

- Located in the middle of the small intestine
- Primary site of nutrient absorption
- Lined with villi (finger-like projections) that increase surface area for absorption
- Contains enzymes that break down carbohydrates, proteins, and fats

Ileum

- Located at the end of the small intestine
- Absorptive surface similar to the jejunum, but fewer villi
- Responsible for absorbing vitamin B12 and bile acids
- Contains lymphatic tissue that helps with immune function

Duodenum

- The first part of the small intestine
- Receives food from the stomach
- Contains the pyloric sphincter, which regulates the flow of food into the small intestine
- Neutralizes stomach acid and mixes it with enzymes from the pancreas and liver

Differences between Jejunum and Ileum

While both the jejunum and ileum are responsible for nutrient absorption, they have some key differences:

- Location: Jejunum is located ближе к началу тонкого кишечника, а подвздошная кишка — ближе к концу.
- Villi: Jejunum has more and larger villi than the ileum, providing a greater surface area for absorption.
- Absorption: Jejunum primarily absorbs carbohydrates, proteins, and fats, while the ileum absorbs vitamin B12 and bile acids.
- Lymphatic tissue: The ileum contains more lymphatic tissue, helping with immune function.

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