Pronunciation: [bɹˈʌʃ bˈɔːdə] (IPA) 
The term 'Brush Border' refers to a collection of microvilli, little finger-like projections on the surface of some cells. These structures are found in various tissues including the small intestine and kidney. The spelling of 'brush' is /brʌʃ/, with a short 'u' sound and a /ʃ/ sound for the 'sh'. 'Border' is spelled /ˈbɔrdər/ with a long 'o' sound and a trilled 'r'. The pronunciation of the entire term is /brʌʃ ˈbɔrdər/.
The brush border is a term commonly used in biology and anatomy to describe a specialized structure found on the surface of certain cells, particularly in the lining of the small intestine and kidney tubules. It refers to a collection of microvilli, tiny finger-like projections that greatly increase the surface area of these cells.
Microvilli are composed of actin filaments covered by a plasma membrane, and when they cluster together, they form a dense brush-like border. This arrangement greatly enhances the absorptive capacity of cells in tissues where nutrients and ions need to be efficiently absorbed or secreted.
In the small intestine, the brush border is found on the surface of epithelial cells that line the intestinal walls. These cells play a crucial role in the digestion and absorption of nutrients from ingested food. The brush border microvilli greatly increase the surface area available for nutrient absorption, allowing for more effective and efficient absorption of molecules such as sugars, amino acids, and vitamins.
Similarly, in the kidney tubules, the brush border is present on the surface of cells responsible for reabsorbing filtered substances, such as glucose, ions, and amino acids, back into the bloodstream. The increased surface area provided by the brush border microvilli facilitates the reabsorption process, ensuring the optimal conservation of essential molecules and ions in the body.
Overall, the brush border is a crucial anatomical structure that enhances the absorptive function of certain cells by increasing their surface area through the presence of microvilli.
The term "brush border" originates from the appearance of the microvilli on the surface of certain cells, particularly the cells lining the small intestine. These microvilli form a densely packed layer that resembles the bristles of a brush, hence the name "brush border". The "brush" in this context refers to the microscopic hair-like structures, while "border" indicates the location of these structures at the edge or surface of the cells.
