Hard-Cornified Cells: The Building Blocks of Nails, Hair, and Claws
When it comes to our nails, hair, and even the claws of animals like cats, it is the hard-cornified cells that play a crucial role. Unlike other types of epithelial cells, these cells do not shed naturally. Instead, they gradually wear away or break, necessitating regular trimming and maintenance.
Cats, for instance, have claws made up of the same type of hard-cornified epithelial cells. However, unlike humans who use files or scissors, cats and many other animals rely on scratching surfaces to remove the outer layer of their claws. By doing so, they reveal a newer layer underneath, keeping their claws sharp and functional.
Interestingly, the cells found in human fingernail clippings and discarded cat claws are remarkably similar. Both are composed of keratin, a fibrous protein that lends strength and durability to these structures.
Functions of Keratins
Keratins are a group of filament-forming proteins found in epithelial cells. These proteins can be categorized as either prekeratins or cytokeratins, based on their chemical and structural properties. While their primary function is to provide protection from external threats, keratins also play various other roles within the body.
One important function of keratin is its involvement in cell signaling. Certain types of keratin filaments help in sending signals to immune cells, enabling the body to mount an appropriate immune response against pathogens. Additionally, keratins can also stimulate the production of hormones, regulating various physiological processes.
Moreover, keratins play a crucial role in intracellular and intercellular transportation. They assist in the transportation of essential substances within cells and facilitate the exchange of molecules between neighboring cells.
In summary, while the main function of keratins is to provide protection, these proteins also contribute to cell signaling, hormone production, and cellular transportation.