FUNCTIONS OF E.R.
(1) Mechanical support - E.R. participates in formation of cytoskeleton with microfilaments, microtubules and intermediate filaments.
(2) Intracellular exchange -E.R. forms intracellular conducting system. Transport of materials in cytoplasm from one place to another may occurs through the ducts of E.R. At many places E.R. remains associated to outer nuclear membrane so nucleo - cytoplasmic transport may occur through E.R. ( E.R. is not the main route here, nucleocytoplasmic traffic mainly occurs through nuclear pores). At some places E.R. also connected to P.M. So E.R. may secrete the materials outside the cell.
(3) Rough E.R. - Participates in protein synthesis.
(4) Lipid secretion - Lipid synthesized by the agranular portion of E.R. (Smooth E.R.), stored into the Golgi before finally being extruded into the cytoplasm as lipid droplet and thence to the outside of cell. The major lipids synthesized by S. E. R. are phospholipids and Cholesterol.
(5) Release of Glucose from Glycogen - The polymerisation of glucose to form glycogen granules probably occur in the hyaloplasm not in the wall of E.R. but the reticulum seems to play a role in the breakdown of glycogen (glycogenolysis).
(6) Cellular metabolism - The membranes of the reticulum provides an increased surface for metabolic activities within the cytoplasm.
(7) Formation of nuclear membrane - Fragmented vesicles of disintegrated nuclear membrane and ER elements arrange around chromosomes to form a new nuclear membrane.
(8) Formation of cell plate.
(9) Formation of lysosomes and Golgi body.
(10) Detoxification - Smooth ER concerned with detoxification of drugs and steroids.