Question

explain three parts of small intestine ​

Answer 1

Parts of the Small Intestine

Duodenum

The duodenum is the first part of this organ, and it is seen in all mammals. This is the smallest portion of the intestine, and is curved, which marks its starting point, as it exits the stomach. This small 12 inch-long portion connects the stomach to the jejunum. However, not to be fooled by its size, this portion has the important function of chemical digestion. Thus, this is the region where there is breakdown of food with the help of enzymes. The duodenum contains tubular submucosal glands known as Brunner's glands. These glands are responsible for secreting mucus, which helps to lubricate the lining of the small intestine, and prevents the enzymes from acting on the cells of this organ. Cholecystokinin is secreted from the duodenum and this has the function of hydrolyzing and digesting fats.

Jejunum

The jejunum comes in second in order. The passage between the duodenum and jejunum is known as the ligament of Treitz. This part is second, both in order, and length, measuring around 8.2 feet. It has a pH that ranges between 7 and 9. This is absolutely essential to carry out the function of this organ because it is only in a slightly alkaline pH that enzymes can work properly in this part of the gastrointestinal tract. When there is any blockage here, food does not manage to pass from the jejunum to the ileum, which leads to pain and bloating of the intestine.

Ileum

The ileum (not to be confused with ilium, which is a part of the pelvic bone) is the longest, and the lowest part of this organ, coming in at 11'6". This part executes the function of absorption of vitamin B12, deficiency of which can lead to megaloblastic anemia. The ileum is slightly pale when compared to the jejunum, and mostly absorbs fatty acids and glycerol, besides glucose and amino acids.