system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What are those white spots at the beginning of the nail? Why do we have/have not them?
gpt
The white half-moon shape at the top of your nail is called the lunula. It’s part of the nail’s “matrix”, aka the root, where new nail cells are formed. If a person doesn’t have visible lunula at all, sometimes it’s because their cuticle grew over it... but other times it can mean that they have a vitamin deficiency and their nails aren’t growing properly because of it. Your cuticles serve a purpose too - they’re the clear layer of skin over the top of your nail. They protect your newly grown nail from getting dirty or infected.