A slit is a fissure or a block which occurs on 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 the grooves of the tires as wear increases the risk of accident", "I was sitting so long that I left a slit on the couch", “When the storm broke, the animal refuge in a cleft of the mountain ”.
In the field of anatomy , is called a cleft or groove to a fold , a depression or one groove . He nasolabial groove or subnasal , to name a case, it is between the nose and the upper lip of the mouth. Formed by two small ridges on the skin, this cleft has a width and length that vary in each person.
It is believed that the nasolabial groove is a trace of the union that, in the ancestors of the human being , existed between the nose and mouth. In animals whose subsistence depends largely on smell, this cleft allows hydrating the snout from the transfer of moisture from the mouth. With human evolution, smell lost preponderance, so the nasolabial groove does not fulfill that function in our species.
The slit drums on the other hand they are percussion musical instruments . It's about a idiophone (his body It is the resonating matter, so it has its own sound) that is made of wood and has several slits so that, when hit, it sounds.
The channel that exists between each pair of cells , through which the molecules can be transferred is known as 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 only one cell layer).
The communication between two cells depends largely on the intercellular cleft, and inside there are narrow junctions, proteins of band desmosomes and junctions gap, thanks to which the propagation and regulation of the signals is possible, among other functions. While 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 them.
In addition to the aforementioned communication between cells, the intercellular cleft plays an auxiliary function in the formation of the barrier blood-nerve that we found around 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 measured depth between the luminal and basal opening has an average of 0.7 microns (one micron is one millionth of a meter).
With respect to the width of the intercellular cleft, along a large part of its length it is around 20 nanometers (one nanometer is equivalent to one billionth of a meter). In the capillaries, it has been determined that the cleft occupies only 0.4 percent of the surface from the wall, and there it diffuses hydrophilic fluids and small solutes freely.