Question

Ileum is
A. First part of the small intestine.
B. Middle part of the small intestine
C. Last part of the small intestine
D. Not a part of the small intestine

Answer 1

A long narrow folded or coiled tube extending from the stomach to the large intestine is known as the small intestine. The small intestine is an organ in the gastrointestinal tract and it lies between the stomach and the large intestine. The small intestine receives secretions from the bile and pancreas. The small intestine consists of 3 parts; duodenum, jejunum, and ileum.

Complete answer: When the food we eat reaches the stomach, it gets mixed with acid and then it moves to the duodenum, the first part of the small intestine. At duodenum, the food gets mixed with bile and digestive enzymes secreted by the gallbladder and pancreas respectively. So, the ileum is not the first part of the small intestine. Duodenum is the first part. From the duodenum, absorption of nutrients begins. The jejunum is the second part of the small intestine. Absorption of sugars, amino acids, and fatty acid take place in the jejunum. So, the jejunum is the second or middle part of the small intestine and not the ileum. Therefore, the ileum is the last part of the small intestine. It is the part that connects the small intestine with the large intestine. Absorption of water and nutrients takes place in the ileum. It is the longest segment of the small intestine.
Hence, the correct answer is option D.

Note: The small intestine has minute projections called villi on its inner surface which helps in the absorption process. In fish, the divisions of the small intestine are not as clear and the terms posterior intestine or distal intestine may be used instead of the ileum.