ENDOPLASMIC RETICULUM AND IT'S TYPES

ENDOPLASMIC RETICULUM

The name endoplasmic reticulum first coined by Poter in 1953.

Occurrence:-

1. It is present both in animal and plant cells.

2. It is absent in egg cells, embryonic cells and RBC of mammals.

3. Nuclear membrane is continuous with endoplasmic reticulum.

Morphology:-

1. Cisternae- The cisternae are long, flattened,sac-like, unbranched tubules having the diameter of 40 to 50 micrometre. They remain  arranged parallely in bundles or stake.

2. Vesicles-The vesicles are oval membrane bound vacuolar structure having the diameter of 25 to 100 micrometre. They often remain isolated in the cytoplasm and occur in most cells but especially abundant in SER.

3. Tubules- The tubules are branched structures forming the reticular system along with the cisternae and vesicles. They usually have the diameter from 50-190 micrometre.

Various type of Endoplasmic reticulum:-

• Smooth endoplasmic reticulum-

          1. It possesses  smooth walls.

          2. Ribosomes are absent in it.

          3. This smooth type of Endoplasmic Reticulum occurs mostly in those cells which are involved in the metabolism of lipids and glycogen.

          4. It is found in adipose cells, interstitial cells, glycogen storing cells of liver, spermatocytes and leukocytes.

• Rough endoplasmic reticulum-

       1. It possesses rough walls.

       2. Ribosomes are present in it.

       3. It is found in pancreatic cells, plasma cells, Goblet cells and liver cells.

       4. Ribosomes play a vital role in the process of protein synthesis.

• Sarcoplasmic reticulum- The smooth endoplasmic reticulum of the muscles cells is known as sarcoplasmic reticulum. It has a special receptor called Rheodyne receptor which is calcium sensing receptor. It releases Ca 2 + ion for muscle contraction.

Enzymes of Endoplasmic reticulum:-

1. The enzymes are present in endoplasmic reticulum membrane.

2. The enzymes are stearases, NADH-cytochrome c- Reductase, NADH diaphorase, glucose-6-phosphotase and mg2+ activated ATPase.

Pic- Endoplasmic reticulam

Know about function of plasma membrane(click it)

If you like our content please subscribe our blog for future notification,

comment for suggestion and tell us what you need to know in the next content.