Modification of Plasma Membrane

In this article we will discuss about:- Microvilli, Inter digitations, Tight junction, Gap junction, Desmosomes and Plasmodesmata

What is Modification of Plasma Membrane?

• Plasma membrane shows some specialized structures
• To perform some additional functions plasma membrane shows some changes

1. Free Surface Modification
2. Junctional Complex

[ Must Read: Fluid Mosaic Model of Plasma Membrane ]

1. Free Surface Modification

Microvilli

• Minute finger like projections arising from surface of certain cells
• Single cell contains more than 3000 microvilli
• Found in epithelial cells of intestine, kidney tubules, gall bladder and hepatic cells
• Function: increase the surface area for absorption

2. Junctional Complex

Inter digitations

• Plasma membrane of adjacent cells project into cytoplasm as finger-like projections
• Found in lymph nodes and lymphoid tissues
• Function: increase surface area for exchange of substance between the cells

Tight junction

• Plasma membrane of adjacent cells fuses by extrinsic proteins
• Found in brain cells, gall bladder and intestinal cells
• Function: adhesion

Gap junction

• Gap junction is channel through two cell membranes across the intercellular space between two adjacent cells
• Found in cardiac muscles
• Function: conduct electrical signals & passage of ions, sugar, vitamin and metabolites

Desmosomes

• Desmosomes are thickened areas of plasma membrane of two adjacent cells
• Found in cardiac muscle and skin cells
• Function: help to glue the cells together

Plasmodesmata

• Cytoplasm of adjacent cell connected with cytoplasmic strands
• Found in plant cells
• Function: exchange of materials between two cells