Nails, which are formed from ectoderm and composed mainly of keratin, have the main function of protecting the ends of the fingers.
Nails are ectodermal derivatives composed of hard keratin whose main function is to protect the ends of the fingers and toes, as well as to handle small objects. In addition, women’s nails also feature decoration function.
Nails are formed by four basic epithelia called the nail matrix, nail bed, proximal nail fold, and hyponychium. The nail matrix is the region where the germinal epithelium is found, that is, where cell proliferation occurs. The cells produced in this region form the nail plate , a structure that covers the nail bed (region just below the nail). The nail plate has a whitish region at the proximal end of the nail, which is called the lunula, and a free edge region. Below the free edge is the hyponychium . The proximal nail fold corresponds to the junction of the nail to the skin.
The nail grows approximately 3mm per month on the hands and only 1mm on the feet. It is estimated that when the fingernail is lost, it takes around four months to regenerate, while the toenail can take up to eight months. The speed of growth can vary from person to person and can also be inhibited due to illness or even malnutrition.
Nails, despite what many think, carry important signs of some pathologies , even if not very specific. In the absence of some nutrients, for example, it is noticed that the nails become opaque, dull and brittle. In hyperthyroidism, there is a weakening of this structure, as in cases of leukemia.
Sometimes, the nails can present diseases, as in the case of onychomycosis . In this condition, fungi attack the nails, which can cause stains, detachment and fall. Another common disease is nail psoriasis, a condition of unknown causes that causes depressions, thickening and detachment of the nail.