Nail growth |process|why nails keep growing – Biology Bug

Do you ever realize that your nails never stop growing. But how do they grow even after cutting? Let me tell you that they are growing before you were born. Nails are hardened structure made of dead cells. They grow by the process of keratinization. Keratin is a protein which is responsible for our hair and nail growth. The article discuss about why there is continuous growth of nails and what are the factors associated with it.

Key points: nail growth, structure of nail, process of growth, role of keratin

Keratin is a protein made by our skin cells. As the cells push upwards to the skin they die and becomes harden. This process is known as keratinization. However there are several other factors which contribute to the growth of nails. Amino acids are required to synthesize any protein in your body. Similarly the amino acids which are required for synthesizing keratin are dependent on amount of Sulfur present in your body. Vitamin A is essential for absorbing this protein. Vitamin C works with zinc to create a protein called collagen. This protein develop healthy connective tissue in your finger and rest of the body. Collagen is also known to be skin tightening and glowing agent. Before we discuss the process in details, let us understand some of facts regarding the nail growth.

1) Growth of the nails depends upon the season. They grow faster in summer than any other season. 2) Fingernails grow faster than toenails. 3) Men show higher rate of growth than women.

Note: Technically nails aren’t growing tissue, hence they do not grow. They are results of those cells which stopped growing due to their genetic mechanism.

Structure of Nail:

The structure includes these important parts,

  1. Matrix
  2. Cuticle
  3. Lunula
  4. Nail bed
  5. Nail plate
  6. Hyponichium
  7. Nail grooves

Matrix: This is the root of the nail. Its function is to make new cells. These new cells pushed up by the old one through the skin. This part contains lots of nerves and blood vessels which are essential for cell reproduction. Technically it is the only living part of the nails at initial stage but ultimately results into dead cells which forms nail.

Cuticle: This is a small sliver of skin where the nail grows out of the finger. It basically protects the matrix from any germs or infections

Lunula: it is a small whitish curved like structure that sometime you see at the bottom of the nails. It can be said as a part of the matrix. Most of the time it is under the skin. Therefore not every individual can see the lunula.

Nail bed: This area lies under nail plate. Nail plate is the visible part of nails which is the result of keratinization.

Hyponichium: this is the line where nail plate separates from nail bed.

Nail grooves: These are the grooves at the side of your free edge which gives direction for nail growth.

Process of Growth

  • The process starts with the DNA and the gene which codes for keratin. Especially in the case of nails there is one gene called as CRATIN which is actively present in our nail cells.
  • This gene will code for the protein i.e. keratin which will be more produced near the nail area.
  • Now the matrix is continuously producing cells because it is rich in blood vessels. The keratin is present in every cell until the cell undergoes a death cycle.
  • As more new cells are produced, the older ones get pushed up by the new cells. This is a sensitive phase where a mineral balance (zinc, iron, cobalt) and hormonal balance is required (minerelocorticoids, thyroxine etc.)
  • The keratin protein in the cells grows harder and beyond a certain point there are no longer living cells with nuclei.
  • The growing hard structure continues to from a nail plate. Most of the growth takes place underside the nail plate and that area is called as germinal matrix. The outer layer of germinal matrix is a half-moon shaped structure that is lunula.
  • The nail plate is loosely attached to the germinal matrix. It also held by some skin at the bottom and at its sides. As it grows the nail will acquire a concave shape.

 Why do we have nails?

The nails are flattened version of claws. It is one of the important features of primates. If you observe the arboreal animals like apes, monkeys, lemurs etc. possess the same feature. Humans are primates and nails are our distinguished character. They are nothing but dead cells and hence not really useful as claws.

Do nails grow after death?

No. it is clearly a myth. Fingernails might appear long after death. It is not because they are still growing but the skin around that area is retracted. If you have carefully observed that the skin and other soft tissues starts shrinking after death. It is an optical illusion which makes the nails look bigger than the ordinary size.

Can they stop growing in certain cases?

This depends on various factors. One of the common reason which we usually see around us is the habit of biting nails. This in certain cases can damage the nail bed or matrix or lunula. If any sensitive area of the nail is damaged because of biting, injury, accident or by using sharpened objects then there is a possibility that the nail might stop growing.

External links:

  1. https://www.livestrong.com/article/181963-what-makes-your-hair-nails-grow/
  2. https://www.aad.org/public/kids/nails/how-nails-grow
  3. https://www.nytimes.com/2015/08/25/science/the-inexorable-forces-of-nail-growth.html
  4. https://classroom.synonym.com/the-process-of-nail-growth-12079176.html
  5. https://nailbees.com/nail-structure

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