Villi: Structure and Fun!Villi: Structure and Fun!(ction)(ction)

By: Guinea McGinnis, Reese’s By: Guinea McGinnis, Reese’s Reser, Pikachu Bui, Tiny GarciaReser, Pikachu Bui, Tiny Garcia

How it worksHow it works The lining of the small intestine is characterized by numerous The lining of the small intestine is characterized by numerous

circular folds called “plicae circulares.” The plicae are lined with circular folds called “plicae circulares.” The plicae are lined with fingerlike villi. From a cross-sectional view, the villus contains a fingerlike villi. From a cross-sectional view, the villus contains a network of capillaries which surround a specialized lymphatic vessel network of capillaries which surround a specialized lymphatic vessel known as a lacteal. The epithelium of an intestinal villus consists of known as a lacteal. The epithelium of an intestinal villus consists of columnar cells which are covered with microvilli. This succession of columnar cells which are covered with microvilli. This succession of folds and projections increases the surface of the intestinal lining for folds and projections increases the surface of the intestinal lining for efficient absorption. Carbohydrates are absorbed by the villi and efficient absorption. Carbohydrates are absorbed by the villi and then enter the capillary. Fat molecules are digested and absorbed then enter the capillary. Fat molecules are digested and absorbed into the epithelial cells of the villus. The fats are formed into clusters into the epithelial cells of the villus. The fats are formed into clusters called chylomicrons which pass into the lacteal. Lymph carries called chylomicrons which pass into the lacteal. Lymph carries chylomicrons away from the villus. Proteins are broken down first chylomicrons away from the villus. Proteins are broken down first into peptides, then into amino acids. These are absorbed into the into peptides, then into amino acids. These are absorbed into the villi, then into the capillary.villi, then into the capillary.

What it looks likeWhat it looks like

Magic School BusMagic School Bus

http://www.youtube.com/watch?v=zJieJ3_http://www.youtube.com/watch?v=zJieJ3_R2DoR2Do

(3:48)(3:48)