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The mysterious power of microvilli: How do they allow our bodies to absorb nutrients?
Microvilli play vital roles in our bodies, especially in the digestive system. These tiny cell membrane protrusions not only increase the surface area, but also optimize the absorption process of nutrients. How do microvilli work? This article will unveil these mysterious powers for you.
The structure of microvilli
Microvilli are small projections covering the cell membrane that significantly increase the cell's surface area. Each microvilli possesses a set of tightly packed cross-linked actin filaments that form the core of the microvilli.
The structural core of each microvilli is composed of 20 to 30 cross-linked actin filaments, which are cross-linked by different bundling proteins.
Microvilli also lack many organelles, allowing them to focus on specific functions, such as absorption and secretion, more efficiently.
Location of microvilli
Microvilli are clustered together in large numbers to form a brush-like border, a structure that is commonly found on the apical surface of some epithelial cells, such as the small intestine.
Microvilli should not be confused with the villi of the intestine, which are made up of many cells, each of which has many microvilli.
Microvilli are also found on the cell membrane of the egg cell, where they help to anchor sperm cells that have penetrated the outer covering of the egg cell. In addition, there are microvilli on the cell surface of white blood cells, which enable white blood cells to move better.
Function of microvilli
In the digestive tract, microvilli are the primary surfaces for nutrient absorption. The membranes of these structures are packed with key enzymes that break down complex nutrients into simpler compounds.
For example, on the surface of the microvilli of cells there are a large number of enzymes that digest carbohydrates. These enzymes are called glycosidases.
This not only increases the surface area of the cells, but also allows for more digestive enzymes to be present, thereby improving the efficiency of nutrient absorption.
The role of the glycocalyx
The surface of the microvilli is covered with the glycocalyx, a thin film composed of peripheral glycoproteins. This layer of structure not only helps the adsorption of substances, but also protects cells from harmful elements.
Clinical significanceThe glycocalyx can be another localization site for functional enzymes.
Damage to microvilli occurs in certain diseases, often because the cell's cytoskeleton undergoes reorganization. For example, in infections caused by Escherichia coli and in chylous malabsorption, microvilli structure may be disrupted.
In some cases, removal of microvilli can be beneficial in combating autoimmune diseases.
Congenital absence of microvilli results in microvillar atrophy in infants, a rare and often fatal condition.
SummaryMicrovilli are key structures in the body that play an important role not only in nutrient absorption, but also in other aspects of cell function. As we gain a better understanding of microvilli, we may be able to find more potential ways to improve health. Doesn't this make us think about how to make better use of this natural design?
