Structure
The general structure of the endoplasmic reticulum is a membranous network of cisterns(sac-like structures) held together by the cytoskeleton. The phospholipid membrane encloses a space, the cisternal space (or lumen), which is continuous with the perinuclear space but separate from the cytosol. The functions of the endoplasmic reticulum vary greatly depending on its cell type, cell function, and cell needs. The ER can even modify to change over time in response to cell needs. The three most common varieties are called rough endoplasmic reticulum, smooth endoplasmic reticulum, and sarcoplasmic reticulum.
The quantity of RER and SER in a cell can slowly interchange from one type to the other, depending on changing metabolic needs. Transformation can include embedment of new proteins in membrane as well as structural changes. Massive changes may also occur in protein content without noticeable structural changes.
Read more about this topic: Smooth Endoplasmatic Recticulum
Famous quotes containing the word structure:
“Why does philosophy use concepts and why does faith use symbols if both try to express the same ultimate? The answer, of course, is that the relation to the ultimate is not the same in each case. The philosophical relation is in principle a detached description of the basic structure in which the ultimate manifests itself. The relation of faith is in principle an involved expression of concern about the meaning of the ultimate for the faithful.”
—Paul Tillich (1886–1965)
“The structure was designed by an old sea captain who believed that the world would end in a flood. He built a home in the traditional shape of the Ark, inverted, with the roof forming the hull of the proposed vessel. The builder expected that the deluge would cause the house to topple and then reverse itself, floating away on its roof until it should land on some new Ararat.”
—For the State of New Jersey, U.S. public relief program (1935-1943)
“One theme links together these new proposals for family policy—the idea that the family is exceedingly durable. Changes in structure and function and individual roles are not to be confused with the collapse of the family. Families remain more important in the lives of children than other institutions. Family ties are stronger and more vital than many of us imagine in the perennial atmosphere of crisis surrounding the subject.”
—Joseph Featherstone (20th century)