Question

How is the small intestine designed to absorb digested food?
A) Lined by epithelium, which is specialized to absorb.
B) Villi are transverse folds of the intestinal wall that increase surface area of absorption.
C) Villi possesses blood capillaries and lacteal (lymph vessels) for quick transport of absorbed food.
D) All of the above.

Answer 1

Hint: Small intestine is a part of the gastrointestinal tract and is the part majority of the absorption from food takes place.

Complete Answer:
Before we find the correct answer, let us find out a little bit more about the small intestine. Small intestine is located between the stomach and the large intestine. It is one the most important parts of the alimentary canal for both digestion and absorption of food.

The small intestine has three regions,
- Duodenum - It is U shaped.
- Jejunum - It is the middle portion and is coiled.
- Ileum - It is highly coiled.

Option A: The mucosa of the small intestine is lined by simple columnar epithelium which has absorptive cells embedded in it. The absorptive cells or enterocytes help in absorption for nutrients and minerals from food in the small intestine.

Option B: Villi in the small intestine are small and finger-like projections which generally extend into the lumen of the small intestine. Size of each villus is around 0.5 -1.6 mm in length. These Finger like projections help in increasing the surface area for absorption of food.

Option C: Villi is made up of a network of capillaries along with a large lymph vessel known as lacteal. This helps in transporting lipid molecules. Also, the intestinal wall is surrounded by blood vessels which also help in transporting the food molecules to various parts of the body.

Option D: As all the statements given above are true, therefore, this is the correct option.

Thus, the correct option is D) All of the above.

Note: The function of small intestine is as follows,
- It helps in complete digestion of food.
- It also helps in absorption of minerals and nutrients from the digested food.
- It transports the undigested food from the small intestine to the large intestine.