How do microvilli enhance absorption in the small intestine?

Microvilli enhance absorption in the small intestine by increasing the surface area for nutrient absorption.

Microvilli are tiny, finger-like projections found on the surface of the epithelial cells lining the small intestine. They play a crucial role in the absorption of nutrients from the food we eat. The primary function of these structures is to increase the surface area of the small intestine, thereby maximising the absorption of nutrients.

The small intestine is the primary site for the absorption of nutrients in the human body. However, if it were smooth, the surface area would be insufficient for the absorption of all the necessary nutrients. This is where microvilli come in. They extend the surface of the small intestine, creating a larger area for absorption. This is similar to how a towel with more fibres can absorb more water.

Each microvillus is covered with a layer of plasma membrane, which contains various enzymes and transporters. These enzymes break down nutrients into smaller, absorbable units, while the transporters help move these nutrients into the cell. This process is known as active transport, where nutrients are moved against a concentration gradient, requiring energy.

Moreover, the microvilli also help in the absorption of water and electrolytes. They contain channels and pumps that facilitate the movement of these substances into the cells. This is particularly important in maintaining the body's fluid and electrolyte balance.

In summary, microvilli are essential structures in the small intestine that enhance absorption. They increase the surface area for nutrient absorption, contain enzymes and transporters for nutrient breakdown and uptake, and facilitate the absorption of water and electrolytes. Without them, our bodies would struggle to absorb the necessary nutrients from the food we eat.