Organelle Structure:
The endoplasmic reticulum contains a network of branching and joining tubules 400 to 700 angstroms in diameter (1 angstrom equals 10-9 m). It has been calculated that 1 ml of liver tissue contains about 11 square meters of endoplasmic reticulum. The encircling membranes are about 50 to 60 angstroms thick and have the same substructure as the plasma membrane. Two patterns are found in the cell, the smooth endoplasmic reticulum and the rough endoplasmic reticulum. The rough endoplasmic reticulum is covered by an evenly spaced arrangement of ribosomal granules. The smooth endoplasmic reticulum lacks ribosomes, which synthesize proteins. The smooth endoplasmic reticulum, rich in a wide variety of enzymes, is most common in cells which are involved in the synthesis of lipids, triglycerides, lipoprotein complexes, and steroids.
Organelle Function:
The function of the endoplasmic reticulum is to transport chemicals between and within cells. It also provides a large surface area for the organization of chemical reactions and synthesis. Two patterns are found in the cell, the smooth endoplasmic reticulum and the rough endoplasmic reticulum. The smooth endoplasmic reticulum packages proteins for transport, synthesizes membrane phosolipids, and releases calcium. Other functions of the smooth endoplasmic reticulum include transformation of bile pigments, glycogenolysis (the breakdown of glycogen), and detoxification of many drugs and chemical agents. In striated muscles, which you use for lifting objects, the endoplasmic reticulum is involved in the conduction of contracting impulses from the surface membrane of the cell into the depths of the muscle cell filled with muscle filaments, which are the basis for muscle contraction.
Interaction With Other Organelles:
The smooth endoplasmic reticulum synthesizes membrane phospholipids which go inward from the endoplasmic reticulum to the nuclear membrane to replace it, or outward to form the golgi complex, lysosomes, and the cell membrane. Most of the membrane phospholipids go to replacing the endoplasmic reticulum membrane itself.
This is a diagram of the smooth endoplasmic reticulum.
http://www.botany.uwc.ac.za/sci_ed/std8/cells/er.html
This is an electron micrograph of the smooth endoplasmic reticulum.
http://esg-www.mit.edu:8001/esgbio/cb/org/smooth_er-em.gif
For more information on smooth Endoplasmic Reticulum go to : http://www.brigadoon.com/~schaffer/biology/vacuole.html
Other organelles that interact with the smooth endoplasmic reticulum are:
1. rough endoplasmic reticulum
4. Ribosomes
5. Lysosomes
To go home: http://sun.menloschool,org/~cweaver/cells/index.html
