Problem 171 - Objective Biology for NEET

Question

Assertion: Villi is supplied with a large lymph vessels called the lacteals. Reason: Chylomicrons transported via lacteals

Step-by-Step Solution

Answer

The assertion and the reason are correct, and the reason accurately justifies the assertion.

Step 1: Verify the assertion

Commence by validating the claim – 'Villi is supplied with large lymph vessels called the lacteals.' This statement is accurate. The small intestine's villi do indeed have lacteals, which are large lymphatic vessels.

Step 2: Verify the reason

Proceed to verify the second statement – 'Chylomicrons are transported via lacteals.' The reason is also correct. After being processed in the intestine, dietary fats form into chylomicrons, which are transported into lacteals for further circulation.

Step 3: Link the assertion and reason

In conclusion, identify if the reason justifies the assertion. Here, the reason (chylomicrons are transported via lacteals) is a mechanism that explains the function of the lacteals mentioned in the assertion, thus justifying why villi are supplied with the lacteals.

Key Concepts

Villi

Villi are tiny, finger-like projections found in the lining of the small intestine. Their main function is to increase the surface area for absorption of nutrients. This feature is crucial because it allows a greater amount of nutrients to come into contact with the intestinal walls and be absorbed efficiently into the bloodstream.

• The increased surface area dictated by the numerous villi ensures that our bodies extract the maximum nutrients from the food we consume.
• Inside each villus is a network of capillaries and a large lymphatic vessel called a lacteal, which assists in the transport of absorbed nutrients.

The combination of capillaries and lacteals enables both the transport of water-soluble and fat-soluble nutrients. This structure showcases just how ingeniously our digestive system is designed to maximize nutrient uptake and distribution.

Lacteals

Lacteals are specialized structures within the villi of the small intestine. They are large lymphatic vessels pivotal in the digestion and absorption process. While the capillaries in the villi absorb water-soluble nutrients like amino acids and simple sugars, lacteals play a different role.
Lacteals are primarily responsible for absorbing larger fatty acids and substances that are not directly soluble in the blood. After fats are broken down in the intestine, they are reassembled into triglycerides and then packaged into chylomicrons.

• These chylomicrons are then absorbed by the lacteals because they cannot enter the blood vessels directly due to their size and composition.
• Once inside the lacteals, the chylomicrons are transported through the lymphatic system before they eventually enter the bloodstream for wider distribution.

Thus, lacteals ensure that crucial fatty nutrients reach the body's cells for energy and other biological functions.

Chylomicrons

Chylomicrons are lipid particles assembled within the intestine during digestion. They serve as the transport vehicles for fats, especially triglycerides, cholesterol, and fat-soluble vitamins. Without chylomicrons, efficient fat absorption and transport would be impossible.
Here's how chylomicrons fit into the digestive landscape:

• After dietary fats are broken down in the intestines, they are transformed back to triglycerides and packaged into chylomicrons.
• These chylomicrons are too large to pass directly into the bloodstream and hence need a different pathway.

Chylomicrons enter the lymphatic system via the lacteals of the villi, where they protect and transport the lipids. This indirect route is crucial because it prevents fats from prematurely clogging the small blood vessels. Eventually, chylomicrons make their way into the bloodstream, where they can deliver fats to cells in need of energy or storage. This pathway demonstrates the intricate coordination within the digestive system to ensure proper nutrition and energy distribution throughout the body.