Question

What are plicae circulares? Give their location and function.

Answer 1

Hint: These are present in the small intestine. They have small projections called villi and microvilli. They increase the area of absorption. These are used for nutrient transport.

Complete answer:
Plicae circulares are present on the inner wall of the small intestine. They are also known as valves of kerckring. They have small projections called villi and microvilli. They increase the area of absorption and transport nutrients to capillaries and lymph vessels for further transport. These folds are 5-6 cm long and 3mm in thickness.

These are present in the intestine throughout except in the duodenum as it is flat and smooth. There is an increase in size of the folds in the terminal portion of duodenum and upper part of jejunum.

Their size starts to decrease from this point eventually disappearing to the lower part of ileum. This fold is round with 3-4 complete turns. It has been seen that there are around 800 plicae circulares in the small intestine and these increase the surface area for absorption to a large extent. The villi are tiny projections present in the plicae circulares. They ate 0.5 -1 mm in height.

Note: Plicae circulares are also known as valves of kerckring. They have small projections called villi and microvilli. They increase the area of absorption. These are present in the intestine throughout except in the duodenum as it is flat and smooth. There is an increase in size of the folds in the terminal portion of duodenum and upper part of jejunum. There size starts to decrease from this point eventually disappearing to the lower part of ileum