Final answer:
Nails are formed by specialized epithelial cells called keratinocytes that originate from the nail matrix found in the nail root, which is responsible for nail growth.
Step-by-step explanation:
Specialized epithelial cells originating from the nail matrix form your nails. These cells, known as keratinocytes, are produced in the nail root and are responsible for nail growth. The area where the keratinocytes proliferate is in the nail matrix, which is a layer of living epidermal tissue at the proximal end of the nail. These stem cells divide to form new cells that add to the nail plate, allowing the nail to grow.