Structure of the Jejunum

The jejunum is approximately 2.5 meters long and is characterized by a thicker wall and a larger lumen compared to the ileum. It has a rich blood supply and a velvety appearance due to the presence of numerous finger-like projections called villi, which increase its surface area for nutrient absorption.

Function of the Jejunum

The primary functions of the jejunum include:

• Continued Digestion: Enzymes produced by the pancreas and the intestinal mucosa continue the breakdown of carbohydrates, proteins, and fats in the chyme, further preparing the nutrients for absorption.
• Nutrient Absorption: The walls of the jejunum are specialized for the absorption of nutrients, including amino acids, sugars, fatty acids, and vitamins, which are then transported to the bloodstream and lymphatic system.

Key Concepts to Understand

When studying the jejunum, it's essential to grasp the following concepts:

• Structure-Function Relationship: Understand how the structure of the jejunum, including its villi and microvilli, enhances its function in nutrient absorption.
• Peristalsis: Learn about the rhythmic contractions of the intestinal muscles that propel chyme through the jejunum, facilitating digestion and absorption.
• Role in Nutrient Transport: Explore how nutrients are transported from the jejunum to the bloodstream and the lymphatic system, and how this process supports overall human nutrition.

Related Topics

As you study the jejunum, consider its connections to the following topics:

• Small Intestine Anatomy: Understand how the jejunum fits into the overall structure and function of the small intestine, including its relationship to the duodenum and the ileum.
• Enzymatic Digestion: Explore the enzymes involved in the digestion of carbohydrates, proteins, and fats, and how they contribute to the breakdown of nutrients in the jejunum.
• Nutrient Absorption: Consider the mechanisms of absorption of specific nutrients in the jejunum, such as the co-transport of glucose and sodium ions.