Question

Pick one surface extension from the plasma membrane and discuss its structure and importance to cell function. (NOT CILIA)

Answer 1

Answer

• The plasma membrane consist of extensions that facilitates the function of a cell.
• Not all plasma membrane contain extension.
• There are mainly 3 plasma membrane extensions : Cilia, microvilli and flagella.

Microvilli

• It is present in the plasma membrane of simple columnar epithelial cell in the mucosa lining of small intestine.
• A villus is a finger-like projection extending from the lumen of small intestine. It contains thin one cell layered wall.
• Each cell from villi contains numerous minute projections on its surface called microvilli. They give brush border appearance to inner surface of small intestinal wall.
  
  
  Function :
• Small intestine is the site for absorption of carbohydrates, proteins and fats.
• Microvilli increases the surface area of absorption by increasing contact of digested food material and mucosa of the small intestine.
• Microvilli enhances the nutrient absorption process.