The small intestine is responsible for the digestion of fats, proteins and carbohydrates, with the nutrients from those being absorbed through the lining of the small intestine into the bloodstream.
There are three features of the small intestine that improve this function: The duodenum, the jejunum and the ileum.
The duodenum is situated at the junction of the stomach and the small intestine; it is shaped like a ‘C’ and is about 25 cm long. The duodenum receives the mixture of partly digested food and stomach acid, though the acid is quickly neutralized by alkaline in the duodenum, which also receives bile from the gallbladder, and other digestive enzymes from the pancreas. Other glands produce mucus that helps the digestive process. All the food mixes with this bile, mucus and enzymes and ensures that the majority of digestion takes place here before the mass travels further into the small intestine to the jejunum.
The jejunum is the coiled mid-section of the small intestine and measures between one and two meters in length; the ileum, which is the final part of the small intestine (and leads into the large intestine) is between two and four metres.
The inner linings of these two sections contain small bumps called villi. This gives them an increased surface area and improves the small intestine’s ability to absorb nutrients. The final stages of digestion take place here and food is broken down into its nutrient components, such as vitamins, minerals, glucose, amino acids, fatty acids, cholesterol, salts and water, where they are absorbed by the villi, which transfers them to the bloodstream and to the liver.
Anything that has not been digested, such as fibre, as well as some vitamins and water, travels on to the large intestine.
There are three features of the small intestine that improve this function: The duodenum, the jejunum and the ileum.
The duodenum is situated at the junction of the stomach and the small intestine; it is shaped like a ‘C’ and is about 25 cm long. The duodenum receives the mixture of partly digested food and stomach acid, though the acid is quickly neutralized by alkaline in the duodenum, which also receives bile from the gallbladder, and other digestive enzymes from the pancreas. Other glands produce mucus that helps the digestive process. All the food mixes with this bile, mucus and enzymes and ensures that the majority of digestion takes place here before the mass travels further into the small intestine to the jejunum.
The jejunum is the coiled mid-section of the small intestine and measures between one and two meters in length; the ileum, which is the final part of the small intestine (and leads into the large intestine) is between two and four metres.
The inner linings of these two sections contain small bumps called villi. This gives them an increased surface area and improves the small intestine’s ability to absorb nutrients. The final stages of digestion take place here and food is broken down into its nutrient components, such as vitamins, minerals, glucose, amino acids, fatty acids, cholesterol, salts and water, where they are absorbed by the villi, which transfers them to the bloodstream and to the liver.
Anything that has not been digested, such as fibre, as well as some vitamins and water, travels on to the large intestine.
