How do finger- and toe-nails grow?

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What are they made out of?

In: Biology

2 Answers

Anonymous 0 Comments

they are made of layers of ‘keratin’ (a protein) — the same protein in hair.

these layers push up towards the top of your nail bed. ie – the nail at the top is the oldest, and at the bottom is the newest growth.

Anonymous 0 Comments

The nail root, which is underneath the fold of skin that goes across the nail, has a layer of cells called the “matrix.” These cells grow, and push out the outermost layer of cells, which die. As the matrix continues to grow and push out old, dead cells, the nail pushes forward.

If your nails have vertical ridges (running from the base to the tip of the nail), it’s because there are lumps or bumps in the nail matrix, which causes the nails to grow unevenly. Most people develop more ridges on their nails as they age. This is normal.

On the other hand, if you have *horizontal* ridges in your nails, you may want to talk to your doctor. Horizontal ridges can be a sign of medical problems. Your nails, like your hair, are actually a good source of information about your health, because they act like tree rings, preserving a record of what happened to you. And, because the cells are continuously growing, they need a lot of blood flow, which means anything in your blood will *probably* show up in your nails, especially things like heavy metal poisoning.