Problem 137 - Objective Biology for NEET

Question

Maximum absorption of digested food takes place in (a) Mouth (b) Stomach (c) Small intestine (d) Large intestine

Step-by-Step Solution

Answer

The most absorption of digested food happens in the (c) Small intestine.

Step 1: Digestion in the Mouth

Digestion begins in the mouth where food is broken down by chewing and the action of salivary enzymes. However, absorption of nutrients does not occur here.

Step 2: Digestion in the Stomach

In the stomach, food is broken down further by gastric juices, but again, absorption of nutrients does not occur in the stomach.

Step 3: Digestion in the Small Intestine

In the small intestine, digestion is completed and most absorption of nutrients occurs. The wall of the small intestine is lined with tiny finger-like projections called villi, which increase the surface area for absorption.

Step 4: Digestion in the Large Intestine

In the large intestine, absorption of water and some minerals occurs. But, it's not the prime organ for absorption of digested food.

Key Concepts

Nutrient Absorption

The process of nutrient absorption is crucial for providing the body with necessary energy and materials to function. After digestion breaks down food into its essential components, absorption takes place mainly in the intestines. These components include:

• Vitamins and minerals
• Proteins broken down into amino acids
• Carbohydrates changed into simple sugars like glucose
• Fats converted into fatty acids and glycerol

The small intestine, in particular, plays a key role in this process. Once absorbed, these nutrients enter the bloodstream and are transported to the cells throughout the body where they are needed. While some water and minerals are absorbed in the large intestine, the primary location for nutrient absorption is indeed the small intestine.

Small Intestine

The small intestine is a remarkable part of the digestive system, primarily because it is the main site where nutrient absorption occurs. It is a lengthy, coiled organ that connects the stomach to the large intestine. Here are some important features of the small intestine:

• It is about 20 feet long, providing a large area for absorption.
• Its internal surface is covered with villi, which significantly increase the surface area for absorption.
• Each villus is covered with even smaller hair-like structures called microvilli, forming the "brush border." This increases the surface area even further.
• The small intestine is divided into three sections: the duodenum, jejunum, and ileum, each playing specific roles in digestion and absorption.

In the small intestine, enzymes and bile continue the digestion of food that began in previous parts of the digestive tract. This efficient absorption system ensures that the body gains maximum nutrients from the consumed food.

Human Physiology

Human physiology encompasses the study of how the body's systems function and interact. Within this vast subject, the digestive system plays a critical role in turning food into energy and nutrients essential for survival. The process of digestion involves:

• The mechanical action of chewing and muscle movements that push food through the digestive tract
• Chemical reactions, involving enzymes and acids, that break down food into smaller molecules
• Coordination between different organs such as the stomach, intestines, and accessory organs like the liver and pancreas

In human physiology, the small intestine stands out as the workhorse for digestion and absorption. With its specialized structure and function, it illustrates the beautifully intricate design of human biology. The seamless integration of digestion, absorption, and nutrient delivery across various systems is an example of the body's efficiency in maintaining health and well-being.