Brush border

Brush border is a term used in anatomy and cell biology to describe the microvilli-covered surface of simple cuboidal epithelium and simple columnar epithelium cells. These cells are found in the small intestine, kidney, and lung among other organs. The brush border greatly increases the surface area of these cells, enhancing their ability to absorb and secrete substances.

Structure

The brush border is composed of microvilli, which are tiny, finger-like projections from the surface of the cell. Each microvillus is covered by a plasma membrane, which contains a variety of enzymes and transporter proteins. These proteins are involved in the absorption and secretion of various substances.

Function

The primary function of the brush border is to increase the surface area of the cell, thereby enhancing its ability to absorb and secrete substances. This is particularly important in the small intestine, where the brush border plays a crucial role in the absorption of nutrients from the digestive tract. The enzymes located on the brush border also play a role in the final stages of digestion, breaking down complex molecules into simpler ones that can be absorbed by the cell.

Clinical significance

Damage to the brush border can lead to a variety of health problems. For example, in celiac disease, an autoimmune disorder, the body's immune system attacks the brush border of the small intestine, leading to malabsorption of nutrients. Similarly, certain infections and medications can also damage the brush border, leading to malabsorption syndrome.

See also

• Microvillus
• Digestive system
• Celiac disease
• Malabsorption