•𝐄𝐍𝐃𝐎𝐏𝐋𝐀𝐒𝐌𝐈𝐂 𝐑𝐄𝐓𝐈𝐂𝐔𝐋𝐔𝐌
The endoplasmic reticulum (ER) is such an extensive network of membranes that it accounts for more than half the total membrane in many eukaryotic cells. (The word endoplasmic means “within the cytoplasm,” and reticulum is Latin for “little net.”) The ER consists of a network of membranous tubules and sacs called cisternae (from the Latin cisterna, a reservoir for a liquid). The ER membrane separates the internal compartment of the ER, called the ER lumen (cavity) or cisternal space, from the cytosol. And because the ER membrane is continuous with the nuclear envelope, the space between the two membranes of the envelope is continuous with the lumen of the ER.
There are two varieties.
• 𝐑𝐨𝐮𝐠𝐡 𝐄𝐑 is the site of protein synthesis resulting from the attached ribosomes.
• 𝐒𝐦𝐨𝐨𝐭𝐡 𝐄𝐑 has three functions:
1. Assists in the synthesis of steroid hormones and other lipids
2. Connects rough ER to the Golgi apparatus
3. Carries out various detoxification processes...
