Inside the cells in the cytoplasm, there are membranes in the form of vessels, bubbles or vacuoles and interconnected flat cavities called endoplasmic reticulum. Endoplasmic reticulum is an organelle that is not static and can be considered as one of the components of a dynamic system that has a relationship with plasma membranes and the outer membrane of the nucleus membrane. While other organelles do not have a direct relationship, but can occur direct interaction or not.
Endoplasmic reticulum functions in a variety of synthesis, can be found in eukaryotic cells and has a structure that resembles a multi-layered sacs. This pouch is called cisternae. The function of the endoplasmic reticulum varies, depending on the type. The Endoplasmic Reticulum (ER) is a labyrinth of the membranes so numerous that the endoplasmic reticulum covers half of the total membrane in eukaryotic cells. (The word endoplasmic means “inside the cytoplasm” and the reticulum is derived from the Latin meaning “tissue”).
Endoplasmic Reticulum Definition
The definition of the endoplasmic reticulum is a group of sacs which shape is a bubble pipe and there is a flat sac that extends inside the cytoplasm of eukaryotic cells.
Endoplasmic Reticulum Types
Endoplasmic reticulum or ER is divided into two types, namely rough endoplasmic reticulum and smooth endoplasmic reticulum. These two types of endoplasmic reticulum will compose a membrane system that covers a space.
The inside of the membrane is called liminal / cisternal space. While the area outside the membrane is called cytosolic space.
The morphological difference between rough ER and smooth ER lies in the lack of ribosomes bound in the membrane facing the cytosolic space.
Rough ER is a membrane-bordered organelle which arrangement consists of a flat bag called a cistern. While the membrane components of the smooth ER are tubular in shape.
The difference in number between the two types of ER is determined by the type of cell. Cells that secrete large amounts of proteins such as pancreatic cells and salivary glands with a large amount of ER.
When viewed in its entirety, rough and smooth ER is distinguished not only according to or whether or not the ribosome is on its membranes but also in its arrangement inside the cytoplasm.
Rough ER shape in the form of long channels and lined curved regularly, while the smooth ER shape such as vessels / tubular or bubbles / vesicular irregular.
Rough and smooth ER are always associated somewhere, because in many ways these two types of endoplasmic reticulum will cooperate in performing cell activity.
Smooth Endoplasmic Reticulum / ER
Smooth ER develops in a number of cell types, for example, such as skeletal muscle cells, renal tubules and also steroid glands. ER proteins vary from cell to cell and depend on functions, such as:
- The occurrence of synthesis of steroid hormones in the gonad gland and kidney cortex
- Detoxification that occurs in the liver has very varied organic components such as barbiturates or ethanol
- The release of 6 glucose phosphates occurs in the liver. Large amounts of glycogen that are in the liver will be stored as granules bound to the outer membrane of the smooth ER.
Rough Endoplasmic Reticulum / RE
In addition to smooth ER, there is also a rough endoplasmic reticulum, called that because of the membrane is attached a lot ribosomes so it will look rough and not slippery when viewed under a microscope.
A characteristic element of rough ER is a thin sheet consisting of two membranes that unite at the edges of each, and also limited by cavities in the form of sacculus sac.
The location and number of sacculus vary depending on the type of cell and the function of its activity.
If the location of the rough ER develops well, then the location of the sacculus will become systematic, more directed and become parallel with each other. There is maxilla in the cells of the glandular cells of the pancreatic acini and parotid.