endoplasmic reticulum - a mandatory organelle of the eukaryotic cell.It is found in the cells of plants, animals and humans.The functions of this component of the cell are varied and are mainly associated with the synthesis, modification and transportation of organic compounds.
first endoplasmic reticulum was detected in 1945.American scientist K. Porter saw her with one of the first electric microscopes.Since that time, it began its active research.
In the cell there are two varieties of this organelle:
- granular, or rough endoplasmic reticulum (covered with a variety of ribosomes).
- of the smooth or smooth endoplasmic reticulum.
reticulum Each type has some features and performs a completely different function.Let's look at them in more detail.
Granular endoplasmic reticulum: the structure .This organelle is a system of cisterns, vesicles and tubules.The walls consist of its bilipidnoy membrane.The width of the cavities can range from 20 nm to a few micrometers - it all depends on the secretory activity of the cells.
have little specialized cells that are characterized by a low level of metabolism, EPS is presented with just a few scattered tanks.Inside the cells that actively synthesize protein, endoplasmic reticulum consists of a set of tanks and an extensive system of tubules.
Typically, granular EPS through the tubules associated with membranes of the nuclear envelope - that way there are complex processes of synthesis and transport of protein molecules.
Granular endoplasmic reticulum: function .As already mentioned, the entire surface by XPS covered cytoplasmic ribosomes, which are known to be involved in protein synthesis.EPS - a place of synthesis and transport of protein compounds.
This organelle is responsible for the synthesis of integral proteins of the cytoplasmic membrane.But in most cases by further protein molecules via membrane vesicles are transported to the Golgi apparatus, where they are further modification according to the needs and distribution of tissues and cells.
In addition, the EPS tanks cavities occur and some changes in the protein - such as accession to the carbohydrate component.Here, formed by the aggregation of large secretory granules.
smooth endoplasmic network: structure and function .The structure of the smooth EPS has some differences.For example, this organelle consists of tanks and has a system of tubules.Complexes such EPS, usually have smaller dimensions, the width of the tank but, on the contrary, more.
smooth endoplasmic reticulum is not related to the synthesis of the protein components, but takes a number of equally important functions.For example, here the synthesis of steroid hormones in humans and all vertebrates.That is why the amount of smooth EPS adrenal cells is quite large.
in liver cells of EPS generates the necessary enzymes that are involved in carbohydrate metabolism, namely in the breakdown of glycogen.It is also known that the liver cells are responsible for the neutralization of toxins.In this organelle tanks the synthesis of a hydrophilic component which is then attached to a toxic molecule increases its solubility in blood and urine.It is interesting that in hepatocytes, which constantly yield to the influence of toxins (poisons, alcohol), almost the entire cage occupied by closely spaced smooth tanks EPS.
in muscle cells has a special type of smooth EPS - sarcoplasmic reticulum.It acts as a depot of calcium handling, so the process of active and quiescent cells.
As you can see, the functions of the EPS are varied and very important for the normal functioning of healthy cells.
