Here's why:
* Protein Synthesis: The ER is the site of protein synthesis and modification. The rough ER, studded with ribosomes, is particularly important in this process.
* Protein Folding: The ER provides an environment for newly synthesized proteins to fold properly and prevent aggregation.
* Protein Transport: The ER acts as a transport system, moving proteins to other parts of the cell, including the Golgi apparatus for further modification and packaging.
Since salivary glands and pancreatic cells are specialized for secreting large amounts of proteins (like digestive enzymes and saliva), they need a highly developed ER to handle this high volume of protein production.
