Membrane is defined as a thin sheet with great flexibility, that is, a membrane is any layer of little thickness that acquires easy mobility and is mostly observed to create separation or adhesion sections.

A clear example that can be mentioned about membranes is at the cellular level, the plasmatic membrane or cell membrane is a type of lamella that allows the separation of the intracellular site from the extracellular one, this membrane is what gives shape and size to the cell, its composition is complex since it is made up of 3 layers, two of them are made up of proteins and one is made up of lipids, that is, the outer and inner membrane have peripheral and intramembranous proteins as their structure, respectively, while the media is composed of a lipid bilayer whose structure is formed thanks to the union of two types of lipids cholesterol and phospholipids (phosphorus ring directed towards the periphery and the lipid chains to the center of the bilayer), acquiring the name of “fluid mosaic” discovered by scientists Nicolson and Singer. Thanks to its structure, the cell membrane has a property and is to be selectively permeable, in turn, they fulfill an important function that is cell transport, since it allows the entry and exit of metabolites to the cell through two processes: endocytosis and exocytosis.

Another mentionable example of the membrane at the body level is the basement membrane, which takes place at the tissue level, the tissues are a group or agglomeration of cells in an orderly manner and which are united to perform a specific function, the base of all these tissues is composed of a small lamella of collagen, giving it the name of “basement membrane” whose main function is to support the different tissues that make up the human body. Like other types of membranes that can be highlighted at the organic level is the mucous membrane, these are fused and adjacent to each other in the cavities to generate a main line of defense against pathogens that is mucus, as an example of the location of these membranes are the nostrils.