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Membrane Meaning 

A membrane is a type of barrier which allows some of the things to pass through it but stops other unwanted substances like molecules, ions, or small particles. The cell membrane is one of the Biological membranes. It separates the interior of all cells with the external environment. The cell membrane is also called a plasma membrane, It is a semipermeable membrane that is composed of lipids and proteins. In order to explain the membrane meaning in simple words, it is just a thin soft pliable sheet or layer, especially in plant and animal cells.

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Cell Membrane Function

Some of the important cell membrane functions are discussed below:

  • Cell membrane helps to protect the integrity of the cell membrane.

  • It provides support and maintains the shape of the cell.

  • The cell membrane regulates the growth of the cells by balancing endocytosis and exocytosis.

  • It plays an important role in signalling the cell and in communication.

  • It acts as the selectively permeable membrane by allowing only selected substances to pass through the cell membrane. 

Type of Membrane:

There are five types of biological membrane found in the human-

  • Mucous Membrane 

It is also called the mucosa. It lines the inside of the cavities that open directly to the exterior environment. Mucous membranes line up the gastrointestinal tract, respiratory tract, reproductive tract, and the urinary tract.

  • Serous Membrane 

It is a line cavity of the body that does not directly open to the external environment. It also covers the organ within the cavities. Serous membrane secretes the serous fluid which allows the organ to glide against something without causing friction.

  • Cutaneous Membrane  

It is also known as skin which covers the full body. It is composed of epithelial cells of many layers which protect the body from external microbes and pathogens. In addition, it also protects from heat, light and injury. 

  • Synovial Membrane 

The junction where two bones meet is called joints and the membrane covering those free joints (shoulder, elbow and knees) is known as the synovial membrane. It secretes the synovial fluid to lubricate the joints freely, making motion much easier.

  • Meninges 

It is a dense connective tissue membrane that covers the brain. Meninges composed of three layers. The outermost layer is called the dura mater, which is a thick connective tissue that prevents the brain from moving too much into the skull. The middle layer is the arachnoid layer that is composed of the loose connective tissue and it appears in the form of a spider web.

The innermost layer is pia mater having a thin layer which directly adheres directly on to the brain.

The different types of membrane process used in our surroundings are:

  • Microfiltration 

It is used to remove suspended solids, bacteria in order to condition the water for disinfectants.

  • Ultrafiltration 

The application of ultrafiltration is similar to microfiltration. Some of the additional uses are to remove dissolved salts with high molecular weight. Such as protein, carbohydrates and also they can remove some viruses.

  • Nanofiltration 

It is used to remove selected dissolved particles from wastewater. Nano filters are more fine compared to ultrafiltration. 

Reverse osmosis and Nanostructures membranes are also artificial membranes just like the membranes discussed above.

Do you know?

Why does the skin of your fingertips swell up with wrinkles after a  long bath? Actually, cells of the finger swell because they have absorbed water from the surrounding. All the cells are wrapped in a semipermeable membrane means that it will allow some water and salts to pass-through while blocking other things. Water naturally flows through a semipermeable membrane from higher concentration to lower concentration, this process is known as osmosis. The water in the cell is less concentrated than the water of the bath. 

FAQ (Frequently Asked Questions)

1. Why Do Cells Need Membrane?

Answer. All living things are made from cells and all cells have a cell membrane or also called the plasma membrane. This cell membrane is semipermeable in nature which allows the necessary things inside the cell stopping the unwanted and toxic particles from entering it. The membrane also provides a fixed environment to the cell separating it from the external environment. With the help of the membrane, the cell can survive in various environments.

2. Is Cell Membrane Amphipathic?

Answer. Yes, the formation of the cell membrane takes place with the help of amphipathic molecules. It helps the proteins to have both polar and nonpolar parts of the cell membrane to do their job. Some of them say that the origin of life has started from amphipathic molecules.