Epithelial polarity

Epithelial polarity

1. Apical surface specializations

   • cilia
   • Flagella
   • Stereocilia
   • Microvilli

2. Lateral surface specializations

   • according to distance between cell membranes
     • Tight junction
       • 1- Provide strong attachment to adjacent cells
       • 2-Prevent passes of material through intracellular space
       • 3- Prevent movement of integral protein from apex to basolateral membrane
     • Adhering junction (acnchoring)
       • 2 general function + Links cytoskeleton of the two cells
     • Gap Junction
       • Maintain direction communication between cells for transmission of ions, amino acids and hormones
       • Allow spreading of excitation waves throughout the heart and smooth muscles
       • Transmit impulse at certain synapse
   • according to the shape of the junction

3. Basal surface specialization

   • Basement membrane