Question

Which is the first part of the small intestine in humans?
a. Duodenum
b. Jejunum
c. Ileum
d. Caecum

Answer 1

Hint: The pyloric portion of stomach opens into the small intestine. The opening of the stomach into the small intestine is guarded by a pyloric sphincter.
The small intestine consists of three parts:-
- U Shaped duodenum
- Middle coiled portion jejunum
- Highly coiled portion ileum.

Complete answer:

> Duodenum: The small intestine or small bowel is an organ in the gastrointestinal tract where most of the end absorption the stomach and curves around the pancreas to end in the region of the left upper part of the abdominal cavity. Which is the first part. So, this option is correct.

> Jejunum: The jejunum is the middle segment of the small intestine found between the duodenum and the ileum. The nutrients present in food are mostly absorbed here and then are passed to ileum. So , this option is not correct.

> Ileum: The ileum is the final section of the small intestine in most higher vertebrates, including mammals. So, this option is also not correct.

> Caecum: a pouch connected to the junction of the small and large intestines. So, this option is also not correct.

Hence, The correct answer is option (A).

Note: The most important function of the small intestine is to break down food and help in absorption of nutrients. The villi present in the small intestine increases the surface area for absorption of food. The villi is richly supplied with blood vessels.
Complete digestion takes place in the small intestine. Fats are digested in the small intestine.
Large globules of fat are converted into the small fat globules for enzymes to work efficiently.
Lipase is the enzyme that catalyse the fat breakdown.