• Microvilli:- Finger like evaginations of plasma membrane which increase surface area of cells for absorption and perform movement with the help of actin filament.
• Lomasomes/Border bodies: Discovered by Moore and Mc Aear. Mesosome like structure located in between the cell wall and cell membrane.
• Occur in fungi and concerned with cell wall synthesis.
• Desmosomes: Thickened circular areas on plasma membrane of adjacent cells with radiating cells with radiating fibrils (tonofibrils) in cytoplasm. Generally occur in epithelial cells and provide cell adhesion.
• Tight junction or Zona Occludence: Outer most layer of two plasma membranes at the site of attachment fuse completely. Fused membrane reveals a 5-layered structure. Permeability of ions is more at tight junction. Tight junction. Tight junction occur in nerve tissue at synapses.
• Gap junction or Nexus: Fine protein channel (connexon) join two plasma membrane of adjacent cells. Exchange of ions between bells may take place by protein channels. Desmosomes, tight junction and Gap junction occurs in animals cell.
• Plasmodesmata: Strasburger (1901) Cytoplasmic connection between two adjacent cells through pores in cell wall and cell membrane. Plasmodesmata are characteristic of multi-cellular plants and they maintain continuity of cytoplasm between adjacent cells.