endoplasmic reticulum

[ en-doh-plaz-mik ri-tik-yuh-luhm ]

noun

, Cell Biology.

1. a network of tubular membranes within the cytoplasm of the cell, occurring either with a smooth surface smooth endoplasmic reticulum or studded with ribosomes rough endoplasmic reticulum, involved in the transport of materials.

endoplasmic reticulum

noun

1. an extensive intracellular membrane system whose functions include synthesis and transport of lipids and, in regions where ribosomes are attached, of proteins

endoplasmic reticulum

/ ĕn′də-plăz′mĭk /

1. An organelle consisting of a network of membranes within the cytoplasm of eukaryotic cells that is important in protein synthesis and folding and is involved in the transport of cellular materials. The endoplasmic reticulum can be continuous in places with the membrane of the cell nucleus. The function of the endoplasmic reticulum can vary greatly with cell type, and even within the same cell it can have different functions depending on whether it is rough or smooth.
2. ◆ The rough endoplasmic reticulum is a series of connected flattened sacs that have many ribosomes on their outer surface. Rough endoplasmic reticulum synthesizes and secretes serum proteins (such as albumin) in the liver, and hormones (such as insulin) and other substances (such as milk) in the glands.
3. ◆ The smooth endoplasmic reticulum is tubular in form and is involved in the synthesis of phospholipids, the main lipids in cell membranes. Smooth endoplasmic reticulum is the site of the breakdown of toxins and carcinogens in the liver, the conversion of cholesterol into steroids in the gonads and adrenal glands, and the release of calcium ions in the muscles, causing muscle contraction. The smooth endoplasmic reticulum also transports the products of the rough endoplasmic reticulum to other cell parts, notably the Golgi apparatus.
4. See more at cell

Word History and Origins

Origin of endoplasmic reticulum¹

First recorded in 1945–50

Example Sentences

By studying late-onset cases, Igdoura and his team uncovered that these diseases begin in the spinal cord, where chronic stress on a cellular component called the endoplasmic reticulum triggers programmed cell death.

From Science Daily

"However, our research highlights a novel function of the HLA molecule within skin cells. We revealed that a specific HLA genotype in keratinocytes can recognize certain drugs as foreign, triggering an endoplasmic reticulum stress response."

From Science Daily

ZIP7 is also the only zinc transporter found in the endoplasmic reticulum, a membranous structure where a cell makes proteins destined for the outer membrane of the cell or for secretion out of the cell.

From Science Daily

The two proteins "sit" at the endoplasmic reticulum exit site, a place in the cell where materials like proteins are packaged and transported out the cell.

From Science Daily

This allows the cytoskeleton to act as a highly dynamic intracellular wiring network to transmit ion-based information from the membrane to the intracellular organelles, including mitochondria, endoplasmic reticulum and the nucleus.

From Science Daily