Problem 100 - Objective Biology for NEET

Question

Which of the following is released in small intestine? (a) Bile juice (b) Pancreatic juice (c) Intestinal juice (d) All of these

Step-by-Step Solution

Answer

(d) All of these

Step 1: Identify the role of Bile Juice

Bile juice is produced by the liver and stored in the gallbladder, which is directly connected to the small intestine. Its main function is to break down fats in food, preparing them for digestion and absorption in the small intestine. Thus, (a) Bile juice is released into the small intestine.

Step 2: Identify the role of Pancreatic Juice

Pancreatic juice consists of digestive enzymes and bicarbonate. It is produced by the pancreas and then transferred to the small intestine to assist in the digestion process. Therefore, (b) Pancreatic juice is released into the small intestine.

Step 3: Identify the role of Intestinal Juice

Intestinal juice is produced by the small intestine itself and aids in the completion of digestion. Thus, (c) Intestinal juice is released into the small intestine.

Key Concepts

Bile Juice

Bile juice is an essential digestive fluid produced by the liver. Its primary role is to break down fats into smaller droplets, a process known as emulsification. This emulsification increases the surface area of fats, making them easier for enzymes to digest.
Once produced by the liver, bile juice is stored in the gallbladder. Upon eating, the gallbladder releases this juice into the small intestine through a tube called the bile duct.

• Emulsification of Fats: Bile juice converts large fat molecules into smaller emulsified droplets.
• Neutralization of Acid: It helps neutralize stomach acid, providing an optimal pH for enzymatic activity in the small intestine.

Bile juice does not contain enzymes, but its role in digestion is crucial for the effective breakdown and absorption of fats.

Pancreatic Juice

Pancreatic juice is a mixture of several critical components that assist in digestion. This juice is secreted by the pancreas and transported to the small intestine via the pancreatic duct. It contains a variety of digestive enzymes and bicarbonate, a substance that neutralizes stomach acid. Here’s how it assists digestion:

• Enzymes: Pancreatic juice contains enzymes such as amylase, protease, and lipase, which digest carbohydrates, proteins, and fats, respectively.
• Bicarbonate: This neutralizes the acidic chyme that enters the small intestine from the stomach, creating a suitable environment for the intestinal enzymes to function effectively.

The combination of these components allows pancreatic juice to break down all major nutrients, thereby playing a comprehensive role in the digestive process.

Intestinal Juice

Intestinal juice, sometimes referred to as 'succus entericus,' is secreted by the cells lining the small intestine. Its primary function is to facilitate the final steps of digestion and nutrient absorption.
Unlike bile and pancreatic juice, intestinal juice is produced by the small intestine itself, providing a convenient function right at the site of digestion.

• Enzymatic Activity: It contains enzymes like maltase, sucrase, and lactase which break down disaccharides into simple sugars.
• Protection and Lubrication: It helps in protecting the intestinal lining and aids in the movement of food along the intestines.

The presence of intestinal juice ensures that the digestion process is completed efficiently, allowing nutrients from the food to be absorbed effectively into the body.