Jejunum

Definition

The jejunum is the second and longest section of the small intestine, located between the duodenum and the ileum. It plays a crucial role in the digestion and absorption of nutrients from the food we consume.

5 Must Know Facts For Your Next Test

1. The jejunum is responsible for the majority of nutrient absorption, including carbohydrates, proteins, and lipids.
2. It contains a large number of villi and microvilli, which greatly increase the surface area for nutrient absorption.
3. The jejunum is highly vascularized, with a rich blood supply that facilitates the transport of absorbed nutrients to the rest of the body.
4. Peristaltic contractions of the jejunal muscles help move food through the small intestine and mix it with digestive enzymes.
5. Malabsorption disorders, such as celiac disease and Crohn's disease, can affect the function of the jejunum and impair nutrient absorption.

Review Questions

• Explain the role of the jejunum in the digestion and absorption of nutrients.
  • The jejunum is the primary site of nutrient absorption in the small intestine. It contains a large number of villi and microvilli, which greatly increase the surface area for the absorption of carbohydrates, proteins, and lipids. The jejunum is highly vascularized, allowing the efficient transport of absorbed nutrients to the rest of the body. Peristaltic contractions of the jejunal muscles also play a crucial role in moving food through the small intestine and mixing it with digestive enzymes, further facilitating nutrient absorption.
• Describe the impact of malabsorption disorders on the function of the jejunum.
  • Malabsorption disorders, such as celiac disease and Crohn's disease, can adversely affect the function of the jejunum and impair nutrient absorption. In celiac disease, the immune system's response to gluten damages the villi in the jejunum, reducing the surface area available for nutrient absorption. Crohn's disease, an inflammatory bowel disorder, can also cause inflammation and damage to the jejunum, leading to malabsorption of essential nutrients. These conditions can result in various nutritional deficiencies and associated health problems if not properly managed through dietary modifications and medical treatment.
• Analyze the role of the jejunum in the overall function of the gastrointestinal system and its impact on an individual's nutritional status.
  • The jejunum plays a critical role in the overall function of the gastrointestinal system by facilitating the absorption of essential nutrients from the food we consume. Its high surface area, rich blood supply, and peristaltic contractions make it the primary site of nutrient absorption in the small intestine. Disruptions to the normal functioning of the jejunum, as seen in malabsorption disorders, can lead to various nutritional deficiencies and associated health problems. This highlights the importance of the jejunum in maintaining optimal nutritional status and overall well-being. Understanding the role of the jejunum in the digestive process and its impact on an individual's nutritional status is crucial for healthcare professionals when assessing and managing gastrointestinal and nutritional disorders.

Related terms

Duodenum:

The first and shortest section of the small intestine, responsible for the initial breakdown and absorption of nutrients from food.

Ileum:

The final and longest section of the small intestine, where the majority of nutrient absorption occurs.

Villi:

Microscopic, finger-like projections that line the inner surface of the small intestine, increasing the surface area for nutrient absorption.