Problem 168 - Objective Biology for NEET

Question

Assertion: Brunner's gland helps in protection of intestinal mucosa from acid Reason: Brunner's gland also secretes mucus

Step-by-Step Solution

Answer

The Brunner's gland does help in the protection of the intestinal mucosa from acid by secreting mucus. So, the assertion and the reason are both correct.

Step 1: Understanding the Roles of Brunner's Glands

The Brunner's glands are found in the submucosa of the duodenum. Their primary function is to produce mucus.

Step 2: The Protective Role of the Produced Mucus

The mucus produced by these glands is alkaline in nature, which helps to neutralize the acidic chyme originating from the stomach. This process protects the intestinal mucosa from acid damage.

Step 3: Confirming the Assertion and Reason

Since the Brunner's gland does secrete mucus that protects the intestinal mucosa from acid, it can be confirmed that the assertion and reason given are both correct. There is, however, an additional point to be noted that the mucus is alkaline which helps counteract the acid.

Key Concepts

Intestinal Mucosa

The intestinal mucosa is a delicate lining that covers the interior of the small intestine, playing a crucial role in digestion and absorption. This layer has to manage substances from the stomach, which can be very acidic. The mucosa itself includes connective tissues, smooth muscle, and underlying layers that absorb nutrients effectively. It serves to both absorb nutrients while maintaining a barrier against potential harmful materials.

When stomach contents (chyme) move into the small intestine, especially the duodenum, they are highly acidic due to the gastric juices. Protecting the intestinal mucosa from this acid is vital to prevent damage or irritation. Any harm to this layer could reduce its ability to absorb nutrients and be painful or damaging. Hence, the body has developed mechanisms, like the secretion of mucus from Brunner's glands, to guard this essential layer.

Alkaline Mucus

Alkaline mucus is an important secretion produced by the Brunner's glands, located in the duodenum, which is the first part of the small intestine. This mucus is slippery and less dense, which helps the chyme move smoothly through the intestinal tract. More importantly, its alkaline nature neutralizes the acid from the stomach.

• The alkaline nature means the mucus has a higher pH level, which counters the acidity of the chyme.
• This neutralization process is significant, as it protects the epithelial cells of the intestinal mucosa from any acidic damage.

Without this mucus, the acid could cause erosion or ulcers in the duodenum. By neutralizing the acid, the mucus provides a safe environment for further digestion and nutrient absorption to occur.

Duodenum Protection

The duodenum, being the first portion of the small intestine, faces a unique set of challenges due to the influx of acidic chyme right from the stomach. Protecting this area is essential to ensure proper digestion and absorption of nutrients.

Brunner's glands play a pivotal role here by secreting alkaline mucus that helps in:

• Neutralizing gastric acids, thereby protecting the duodenum's lining from acid corrosion.
• Providing a suitable pH level for the optimal function of pancreatic enzymes, which require a less acidic environment.
• Aiding in the smooth passage of chyme through the intestinal tract, preventing physical damage from rough or acidic foods.

This protection ensures the duodenum can safely process incoming chyme while starting the next phase of digestion. Without such protective mechanisms, the body's ability to digest food efficiently could be compromised.