Definition of Smooth Endoplasmic Reticulum in Biology

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Figure 2. Dendritic vertebral function. a) Spines are the main sites of excitatory synaptic transmission. Spines exist to (b) amplify the electrical potential at the synapse and (c) promote associativity between adjacent synapses. The shape of the spine and the strength of the neck of the spine can affect the potential (V) generated by synaptic activation. d) Spines exist as molecular compartments. The smooth endoplasmic reticulum (tubules), calcium and a variety of other signalling mechanisms (stippling) are recruited in response to synaptic activation (asterisks). (e) Three-dimensional reconstruction of thin spines resulting from dendrite. Polyribosomes (blackheads) are the most common at the base of dendritic spines, although they can also appear there.

The smooth endoplasmic reticulum is present in almost all eukaryotic cells. However, some eukaryotic cells lack sER, such as eggs, embryonic cells and mature red blood cells. Conversely, some specialized cells are rich in sER. Examples of cells with abundant SER include sebaceous glands, gonadal cells involved in the production of steroid hormones (such as Leydig cells in the testicles and follicular cells in the ovary), hepatocytes in the liver, and striated muscle cells. There are two types of endoplasmic reticulum: the coarse endoplasmic reticulum (rough ER) and the smooth endoplasmic reticulum (smooth ER). Both types are found in plant and animal cells. The two types of ER often appear separate, but they are sub-compartments of the same organelle. Cells that specialize in protein production tend to have a greater amount of coarse ER, while cells that produce lipids (fats) and steroid hormones have a greater amount of smooth ER. To prevent the endoplasmic reticulum from growing beyond the needs of the cell, small vesicles called ER vesicles or transport vesicles continually detach from the smooth reticulum; Most of these vesicles then migrate quickly to the Golgi apparatus.

1. Which of them applies to the smooth endoplasmic reticulum? Has. According to the intermediate filaments of the cytoskeleton B. Made of tubular tanks that have 100 nm diameter C. Interaction with mitochondria affects a number of their D functions. All this The role of the smooth endoplasmic reticulum in the storage and release of calcium ions is of particular importance in the cells of the nervous and muscular systems that use calcium-mediated signals for excitation and contraction. Under resting conditions, the ER light may be partially full. After a large influx of calcium into the cell during excitation, the smooth endoplasmic reticulum can act as a well, allowing cells to recover from the effects of membrane depolarization.

The emergency room can store and release calcium ions in complex ways and, in some scenarios, may even be involved in creating a „memory“ of neural activity. In skeletal muscle cells, SER comes in the form of a specialized membrane structure known as the sarcoplasmic reticulum. The sarcoplasmic reticulum is a critical location for calcium ions that absorb ions from the cytoplasm. It also releases calcium ions when the muscle cell is triggered by nerve stimuli, resulting in muscle contraction. In this way, the sarcoplasmic reticulum helps regulate calcium ion concentrations in the cytoplasm of skeletal muscle cells. The sarcoplasmic reticulum is also found in smooth muscle cells, although in a looser form than in skeletal muscle. Cytochrome P450s reductase is a membrane enzyme found in the smooth endoplasmic reticulum. It is a rare condition caused by cytochrome P450s reductase enzyme deficiency. This disorder affects steroid hormones, which are essential for normal development and reproduction, and affects the development of the skeletal system, the reproductive system and many other parts of our body. Symptoms and signs of cytochrome P450 oxidoreductase deficiency range from mild to severe.

People with moderate forms of the disorder may have ambiguous genitals and be sterile. The most severe form of the disease is called Antley-Bixler syndrome. Antley-Bixler syndrome is characterized by skeletal abnormalities, especially bones in the head and face, including craniosynostosis (premature fusion of the bones of the skull), a flattened middle of the face, a prominent forehead, and deep ears. Enzymes located in the endoplasmic reticulum (ER) present at these sER sites are responsible for the synthesis of the vast majority of cellular lipids. The sER therefore plays an important role in balancing the different categories and classes of lipids and thus in the influence of cellular lipid biomass. These enzymes located in the ROEs are initiated by signals from outside and inside the cell. The cellular lipids synthesized by sER provide the cell with membrane lipids, which are essential for growth-based and differentiation-based changes in cell morphology and structure. They also help maintain membrane homeostasis throughout the cell. The structure of the smooth emergency room is especially important in two types of cells in the human body – muscle cells and neurons. The presence of a large emergency network along the neuron is closely related to its interaction with actin and microtubules, and the organelle forms a continuous network throughout the cell. It is present in small dendritic spines, along the narrow axon, and is distributed through the synapse. At the synapse, the smooth emergency room is often associated with mitochondria.

Even when the cytoskeleton depolymerizes and the ER tubule network undergoes major morphological changes, the association between mitochondria and smooth ER Remains intact. In muscle cells, the smooth endoplasmic reticulum is called the sarcoplasmic reticulum and is an important place to store calcium ions. The longitudinal arclasmic reticulum is a network of many interconnected tubules around each myofibrill. The longitudinal columns connect at their ends to form a single, enlarged bag-shaped formation called a terminal tank. The longitudinal and junctional sarcoplasmic reticulum (SR) shows a specific spatial organization in relation to myofibrils, which are regularly aligned with specific regions of the sarcomeres. The endoplasmic reticulum performs the following functions: The smooth endoplasmic reticulum (Fig. 1.5A) is associated with carbohydrate metabolism and many other metabolic processes, including detoxification and synthesis of lipids, cholesterol and steroids. The membranes of the smooth endoplasmic reticulum serve as surfaces for the fixation of many enzyme systems, for example: the cytochrome P450 enzyme, which is involved in important detoxification mechanisms and is therefore accessible to its substrates, which are usually lipophilic.

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