Final answer:
Fingernails are modifications of the epidermis composed of keratin-filled keratinocytes. They act as protective plates, enhance sensation, and as tools. Nails grow from the nail bed's nail matrix and contain no nerve endings, making trimming pain-free.
Step-by-step explanation:
What Are Fingernails?
Fingernails are a modification of the epidermis, the outermost layer of skin. They are composed of dead keratinocytes, which are cells filled with the tough protein keratin. This keratin content makes the nails hard but flexible, fulfilling several roles. First, fingernails act as protective plates over the ends of fingers, assisting in injury prevention. They also contribute to enhanced sensation by serving as a counterforce to the sensitive fingertips during touch and handling of objects. Additionally, fingernails can be utilized as tools in various tasks.
The nail itself grows from a part of the nail bed known as the nail matrix, which is a layer of living epidermal tissue. The stem cells in the nail matrix keep dividing, allowing the nail to grow longer by pushing older cells forward as the nail extends outward from the nail bed. It's interesting to note that there are no nerve endings in the nail itself, making the cutting of nails a painless process.
Nails are part of the integumentary system, and in function and structure, they can be likened to claws found in other animals. As nails grow, there are three main parts that can be identified: the root, plate, and free margin. The area under the nail is rich in nerve endings, which is why it can be sensitive to touch and pain when injured.