Related Concept Videos

Renewal of Intestinal Stem Cells01:23

Renewal of Intestinal Stem Cells

The intestinal epithelial lining rapidly renews every 4 to 5 days. The renewal is facilitated by intestinal stem cells (ISCs) located at the base of the crypt– a gland located at the bottom of each villus. ISCs divide asymmetrically to form new stem cells and progenitor daughter cells. The daughter cells are called transit-amplifying (TA) cells which move upwards along the crypt and either differentiate into absorptive cells– the enterocytes or secretory cells– including the goblet,...
Microvilli00:55

Microvilli

Microvilli are tiny finger-like projections found on the surface of certain cells. Their purpose is to increase the surface area of the cell's apical surface, resulting in more effective absorption or secretion of substances.
These microvilli are predominantly present in cells lining the small intestine, kidney tubules, and certain cells in the respiratory and reproductive systems. By significantly expanding the surface area of the cell membrane, microvilli enhance the cell's capacity to...
Histology of the Small Intestine01:27

Histology of the Small Intestine

The small intestine exhibits a unique histological structure that significantly enhances its function in digestion and nutrient absorption. These structures include circular folds, villi, and various specialized cells that collectively facilitate the digestion of food.
The intestinal lining features transverse folds called circular folds, each housing fingerlike projections known as intestinal villi. These villi are covered by a layer of simple columnar epithelium, also referred to as...
Absorption of Nutrients01:19

Absorption of Nutrients

Absorption refers to taking dietary nutrients from the intestinal lumen for transportation throughout the body. After digestion in the small intestine, carbohydrates, proteins, and fats are broken down into simpler forms. These essential macronutrients and other vital substances, such as vitamins, minerals, and water, are then prepared for absorption into the bloodstream.
Enterocytes, which are specialized polar epithelial cells, line the mucosa of the small intestinal walls. These cells...