The jejunum is the second and longest part 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.
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The jejunum is approximately 2.5 meters (8 feet) long and has a larger diameter than the duodenum or ileum.
The jejunum contains a large number of circular folds, called plicae circulares, which increase the surface area for nutrient absorption.
The jejunum is highly vascularized, meaning it has a rich blood supply to facilitate the efficient absorption of nutrients into the bloodstream.
Digestive enzymes secreted by the pancreas and liver are released into the jejunum, where they continue the breakdown of food components.
The jejunum is responsible for the absorption of most carbohydrates, proteins, and lipids, as well as vitamins and minerals.
Review Questions
Describe the anatomical location and function of the jejunum within the gastrointestinal system.
The jejunum is the second and longest section of the small intestine, situated between the duodenum and the ileum. Its primary function is to continue the digestive process by further breaking down food components and facilitating the absorption of nutrients, such as carbohydrates, proteins, lipids, vitamins, and minerals, into the bloodstream. The jejunum is highly vascularized and contains numerous circular folds, called plicae circulares, which increase the surface area for efficient nutrient absorption.
Explain the role of the jejunum in the context of the introduction to the small and large intestines.
Within the introduction to the small and large intestines, the jejunum is highlighted as the second and longest section of the small intestine, playing a crucial role in the digestive and absorptive processes. The jejunum receives partially digested food from the duodenum and is responsible for the majority of nutrient absorption, including carbohydrates, proteins, lipids, vitamins, and minerals. Its high vascularity, circular folds, and digestive enzyme secretions all contribute to the efficient absorption of these essential nutrients before the remaining waste material enters the large intestine.
Analyze how the anatomical and functional characteristics of the jejunum relate to the overall introduction of the gastrointestinal system and oral cavity.
The jejunum, as part of the small intestine, is a key component of the overall gastrointestinal system, which begins with the oral cavity and continues through the various sections of the digestive tract. The jejunum's anatomical features, such as its length, diameter, and the presence of circular folds, are specifically adapted to facilitate the efficient digestion and absorption of nutrients from the food that has been broken down in the earlier stages of the gastrointestinal system. Additionally, the jejunum's rich blood supply and the secretion of digestive enzymes from the pancreas and liver highlight its crucial role in the overall functioning of the gastrointestinal system, connecting the processes that begin in the oral cavity to the final stages of nutrient absorption and waste elimination.
The first and shortest section of the small intestine, responsible for receiving partially digested food from the stomach and continuing the digestive process.
The final and longest section of the small intestine, where the majority of nutrient absorption occurs before the remaining waste material enters the large intestine.
Tiny, finger-like projections that line the inner surface of the small intestine, including the jejunum, to increase the surface area for nutrient absorption.