Both digestion and absorption happen in which of the following parts of the digestive system?
A.
Gallbladder
B.
Esophagus
C.
Stomach
D.
Small intestine
The Correct answer and Explanation is:
The correct answer is:
D. Small intestine
Explanation:
Digestion and absorption are crucial processes in the digestive system, and they primarily occur in the small intestine.
Digestion is the process by which food is broken down into smaller molecules that can be absorbed by the body. Absorption is the process by which these digested nutrients pass through the lining of the small intestine into the bloodstream, where they can be distributed to cells throughout the body.
- Small Intestine: The small intestine is the most important site for both digestion and absorption. It is divided into three parts: the duodenum, jejunum, and ileum. The duodenum receives chyme from the stomach along with bile from the gallbladder and digestive enzymes from the pancreas. These enzymes help in breaking down carbohydrates, proteins, and fats into smaller molecules. The jejunum and ileum are primarily responsible for absorbing nutrients into the bloodstream. The walls of the small intestine are lined with tiny, finger-like projections called villi, which increase the surface area for absorption. Microvilli, even smaller projections on the villi, further enhance nutrient absorption.
- Other Digestive Organs:
- Gallbladder: The gallbladder stores and releases bile into the small intestine but does not participate in digestion or absorption directly.
- Esophagus: The esophagus is a muscular tube that transports food from the mouth to the stomach. No digestion or absorption occurs here.
- Stomach: The stomach is primarily involved in digestion, especially of proteins, but very little absorption occurs here, except for some substances like alcohol and certain medications.
The small intestine is where the majority of digestion is completed and where almost all nutrients—carbohydrates, proteins, fats, vitamins, and minerals—are absorbed. This makes it the primary organ for both digestion and absorption in the digestive system.