What Does cleft Mean
A cleft is a fissure or gash in a solid surface that does not separate or divide. The term is also used to name a narrow and shallow opening .
For example: "It is important to control tire grooves as wear increases the risk of an accident" , "I sat for so long that I left a groove on the sofa" , "When the storm broke, the animal took refuge in a cleft of the mountain ” .
In the field of anatomy , a crease , a depression or a groove is called a groove or groove . The nasolabial or subnasal sulcus , to cite one case, is located between the nose and the upper lip of the mouth. Formed by two small ridges in the skin, this cleft has a width and a length that vary in each person.
It is believed that the philtrum is a sign of the union, the ancestors of the human being , existed between the nose and mouth. In animals whose subsistence depends largely on smell, this cleft allows the muzzle to be hydrated from the transfer of moisture from the mouth. With human evolution, smell lost its preponderance, which is why the nasolabial fold does not fulfill this function in our species.
The slit drum , on the other hand, are percussion instruments . It is an idiophone (its body is the resonating matter, that is why it has its own sound) that is made of wood and that has several indentations so that, when struck, it sounds.
The channel that exists between each pair of cells , through which the molecules can move, is known as the intercellular cleft . More precisely, we find it in epithelial cells, that is, those that cover the different surfaces of our body and are found in the skin, organs and blood vessels. The intercellular cleft can also be seen in the endothelium of the lymphatic and blood vessels (the endothelium is a tissue that has a single cell layer).
The communication between two cells depends largely on the intercellular gap, and inside there tight junctions, desmosomal proteins in band and joints gap , through which it is possible to spread and control signals, among other functions . Although the cleft is nothing more than a channel, everything that flows through it, such as ions and small molecules, are essential for the cells around it.
In addition to the aforementioned communication between cells, the intercellular cleft plays an auxiliary role in the formation of the blood-nerve barrier that we find around the nerves . It is a necessary component to transport small solutes and fluids inside the endothelium.
Each intercellular cleft has different dimensions, depending on the part of the body to which it belongs, but certain approximate values have been established that serve to define the length, width and other of its properties. For example, in capillaries , the average length is around 20 meters per square centimeter. Its depth measured between the luminal aperture and the basal aperture averages 0.7 microns (a micron is one millionth of a meter).
With respect to the width of the intercellular cleft, throughout a large part of its extension it is around 20 nanometers (a nanometer is equal to one billionth of a meter). In capillaries, it has been determined that the cleft occupies only 0.4 percent of the wall surface , and there it diffuses hydrophilic fluids and small solutes freely.