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Patient care — general information

Small intestine - the part of the gastrointestinal tract (gut) between the stomach and the large intestine and comprises the duodenum, jejunum, and ileum. It is where the vast majority of digestion takes place.

In humans over 5 years old it is approximately 7 m (21 ft) long and can vary from 4-7 m (13.12-22.97 ft). The small intestine is divided into three structural parts: the duodenum, the jejunum, and the ileum.

Although the small intestine is much longer than the large intestine (typically 4-5 times longer), it is referred to as such due to its comparatively smaller diameter. On average, the diameter of the small intestine of an adult human measures approximately 2.5-3cm, and the large intestine measures about 7.6 cm in diameter. This is where bile is released into, from the gall bladder.

Food from the stomach is allowed into the duodenum by a muscle called the pylorus, or pyloric sphincter, and is then pushed through the small intestine by a process of muscular-wavelike contractions called peristalsis.


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