File:0313 Endoplasmic Reticulum b en.png

Caption: (a) The ER is a winding network of thin membranous sacs found in close association with the cell nucleus. The smooth and rough endoplasmic reticula are very different in appearance and function (source: mouse tissue). (b) Rough ER is studded with numerous ribosomes, which are sites of protein synthesis (source: mouse tissue). EM × 110,000. (c) Smooth ER synthesizes phospholipids, steroid hormones, regulates the concentration of cellular Ca++, metabolizes some carbohydrates, and breaks down certain toxins (source: mouse tissue). EM × 110,510. (Micrographs provided by the Regents of University of Michigan Medical School © 2012)
URL: https://cnx.org/contents/FPtK1zmh@8.108:fV7KwqTE@5/The-Cytoplasm-and-Cellular-Org
Version 8.25 from the Textbook
OpenStax Anatomy and Physiology