A brush border (or striated border or brush border membrane) is the name for the microvilli-covered surface of simple cuboidal epithelium and simple columnar epithelium cells found in certain locations of the body. Microvilli are approximately 100 nanometers in diameter and their length varies from approximately 100 to 2,000 nanometers in length. Because individual microvilli are so small and are tightly packed in the brush border, individual microvilli can only be resolved using electron microscopes; with a light microscope they can usually only be seen collectively as a fuzzy fringe at the surface of the epithelium. This fuzzy appearance gave rise to the term brush border, as early anatomists noted that this structure appeared very much like the bristles of a paintbrush.
Brush border cells are found in two main locations:
- The small intestine tract: This is where absorption takes place. The brush borders of the intestinal lining are the site of terminal carbohydrate digestions. The microvilli that constitute the brush border have enzymes for this final part of digestion anchored into their apical plasma membrane as integral membrane proteins. These enzymes are found near to the transporters that will then allow absorption of the digested nutrients.
- The kidney: Here the brush border is useful in distinguishing the proximal tubule (which possesses the brush border) from the distal tubule (which does not).
The brush border morphology increases a cell's surface area, a trait which is especially useful in absorptive cells. Cells that absorb substances need a large surface area in contact with the substance to be efficient.
In intestinal cells, the microvilli are referred to as striated border, while in the kidneys, microvilli are referred to brush border.
Other articles related to "brush border":
... Peptides are further digested when they enter the villi, where brush border peptidase break proteins into amino acids ... in celiac gut, but in normal gut is broken down by brush border peptidases ... a lower peptidase activity that explains the presence of these peptides behind the brush border membrane ...
... appearance, groups of these microvilli are known collectively as the brush border ... Sodium and water are transported across the brush border along with the sugars in this process ... the water that normally would have been transported across the brush border with the sugar instead remains in the intestinal tract to be expelled with the stool ...
Famous quotes containing the words border and/or brush:
“Swift while the woof is whole,
turn now my spirit, swift,
and tear the pattern there,
the flowers so deftly wrought,
the border of sea-blue,
the sea-blue coast of home.”
—Hilda Doolittle (18861961)
“Oh, lets go up the hill and scare ourselves,
As reckless as the best of them tonight,
By setting fire to all the brush we piled
With pitchy hands to wait for rain or snow....”
—Robert Frost (18741963)