Sophia Delgado
Fingernails and toenails are made of a tough, rigid protein called alpha-keratin, which is also found in claws, hooves, and horns of vertebrates. Nails are present in primates, including humans, and are thought to be an evolutionary variation of claws. They are protective plates that cover the tips of our fingers and toes, and they have several functions. For example, they help us grip objects, use our hands for intricate tasks, and protect our fingers and toes from injuries and infections. Fingernails grow at a rate of about 3.5 mm per month, while toenails grow slower at around 1.6 mm per month. The health of our nails can also indicate our overall health and nutrient deficiencies.
| Characteristics | Values |
|---|---|
| Biological function | Help with manual tasks, provide counter pressure when gripping small objects, and aid in climbing or sprinting |
| Composition | Made of a tough rigid protein called alpha-keratin, a polymer also found in claws, hooves, and horns of vertebrates |
| Growth rate | Fingernails: 3.5 mm per month; Toenails: 1.6 mm per month |
| Regrowth time | Fingernails: 3-6 months; Toenails: 12-18 months |
| Health indicators | Nail appearance can indicate nutrient deficiencies, illness, drug reactions, poisoning, or local injury |
| Blood flow | Fingernails have greater blood flow due to their proximity to the heart |
| Permeability | More permeable than skin, allowing for the penetration of harmful and medicinal substances |
| Protective function | Provide a hard, protective shell for vulnerable fingertips and toes |
| Nerve endings | Intricate network of nerves underneath the nail that enhance sensation |
| Grooming | Useful for removing lice, ticks, and other pests from the skin and hair |
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What You'll Learn
Fingernails and toenails protect the tips of our digits
Fingernails and toenails are protective plates found at the tips of the digits (fingers and toes) of primates, corresponding to the claws in other tetrapod animals. Nails are made of a tough, rigid protein called alpha-keratin, which is also found in the claws, hooves, and horns of vertebrates. The nail consists of the nail plate, the nail matrix, and the nail bed below it, with the nail matrix generating new cells that harden as they move outward from the nail root to the nail plate.
The main function of nails is to protect the tips of our digits. They provide a hard, protective shell for our vulnerable fingertips and toes, which are packed with nerve endings and blood vessels. This protection is especially important for our toes, as the tops of our toes are vulnerable to injury and infection.
In addition to their protective role, fingernails also enhance the function of our fingers, enabling us to perform manual tasks more easily. They provide a solid surface for the pads of our fingers to press against when gripping objects tightly. This helps to create counter pressure when gripping small objects and aids in our dexterity and fine motor functions.
The pressure from fingernails also increases sensation in the fingertips, which is useful for delicate tasks. The network of nerves underneath the nails contributes to our sense of touch.
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Fingernails help us grip and pick up small objects
Fingernails are an important part of the sense of touch. They provide a solid surface for the pads of the fingers to press against, enhancing the function of our fingers and enabling us to perform manual tasks more easily.
The pressure from the fingernails causes a build-up of pressure in the fingertips, increasing sensation for delicate tasks. This build-up of pressure gives us greater dexterity and agility when manipulating small objects.
Fingernails also provide counter-pressure when gripping small objects. This counter-pressure helps to prevent the fingertips from bending backward when holding or picking up small items.
The existence and strength of fingernails are essential for this function, and their protective shell covers the vulnerable fingertips. Fingernails are made of a tough, rigid protein called alpha-keratin, which forms a hard, flattened claw at the end of each finger.
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Toenails grow slower than fingernails
The difference in growth rate between fingernails and toenails is likely due to a variety of factors, including use, trauma, blood flow, and evolution. Fingernails have greater blood flow, partly because they are closer to the heart. The legs and feet are also more prone to issues with blood flow, such as deep vein thrombosis, which can impact toenail growth and function.
The frequency and strength of mechanical forces on the nail bed can also change the rate of nail growth. For example, carpenters, who subject their nails to more mechanical forces than office workers, tend to have flatter nails that grow more slowly. Similarly, nail biting has been observed to increase the rate of nail growth, possibly due to the increased blood and nutrient supply to the affected area.
The evolution of nails from claws may also play a role in the difference in growth rate between fingernails and toenails. Nails are one of the features that distinguish primates, having evolved from claws around 55 million years ago. While claws are ideal for gripping tree trunks, the flat shape of nails allows for greater dexterity and precision when manipulating small objects. The main function of toenails is likely protection, while fingernails enhance grip and fine motor functions.
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Nails are made of a protein called alpha-keratin
Nails are made of a tough, rigid protein called alpha-keratin, a polymer also found in the claws, hooves, and horns of vertebrates. Keratin is a tissue type that has amino acid proteins. It is naturally present in hair and nails and is also a component found in other animals, including horse hooves.
The nail consists of the nail plate, the nail matrix, and the nail bed below it, along with the grooves surrounding it. The nail plate is the technical term for the part that we call the "nail". It is made of a hard substance called keratin and is about half a millimeter thick and slightly curved. The nail plate is formed by the matrix, which constantly produces new keratin that gathers and slowly pushes the nail forward, causing it to grow. The nail matrix is also known as the matrix unguis, keratogenous membrane, or onychostroma. It is the part of the nail bed that is beneath the nail and contains nerves, lymph, and blood vessels. The matrix produces cells that become the nail plate. The width and thickness of the nail plate are determined by the size, length, and thickness of the matrix, while the shape of the fingertip bone determines the shape of the nail plate.
The formation of a nail begins inside a part of the fingertip called the nail root. This is where the cells that will eventually form the nail plate gradually die, harden, and push out of the skin. As older cells are compacted and pushed out by the formation of new cells, they take the hardened, flattened form of the fingernail. Toenails are made in the same way as fingernails. The cuticles are a thin waterproof membrane that seals the nail plate to the fingertip, providing an important barrier against infections.
The keratin cells link together to form the nail's consistency and feel. For example, the nail layers are made of soft, moderately hard, and hard keratin. These layers come together to create the protective shield that covers the sensitive nerve endings and blood vessels underneath.
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Fingernails can indicate nutrient deficiencies
Fingernails and toenails are made of a tough, rigid protein called alpha-keratin, which requires nutrients to produce. Nails can be a map of what's going on inside your body, and nutrient deficiencies may affect their appearance.
Nails are a protective plate at the tip of the digits (fingers and toes). They are made of a protein called keratin, which requires nutrients to produce. Therefore, any nutritional deficiency can produce significant changes in the nail plate.
For example, low calcium levels can cause dry, brittle nails. A vitamin B12 deficiency can also affect the colour of your nails, causing them to become bluish or grey-brown. Spoon nails, where the nail appears concave either horizontally or vertically, can indicate an iron deficiency. Soft, flaky nails that break or split may be a sign of reduced plasma magnesium levels. White fingernails have been associated with low selenium levels, and clubbing of nails is linked to cretinism caused by iodine deficiency. Vitamin A and D deficiencies have been linked to soft nails (hapalonychia).
Beau's lines, or transverse linear depressions in the nail plate, can be caused by protein deficiency and the malnourished state associated with chronic alcoholism. They can also be caused by any disease severe enough to disrupt normal nail growth. The width of the furrow can indicate the duration of the ailment.
It is important to note that nail changes in nutritional deficiencies are usually minor and non-specific, and it is often difficult to suspect a nutritional deficiency solely by observing nail changes.
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Frequently asked questions
Nails are made of a tough rigid protein called alpha-keratin, a polymer also found in the claws, hooves, and horns of vertebrates.
Fingernails help enhance the function of our fingers, enabling us to perform manual tasks more easily. Toenails, on the other hand, likely serve a protective purpose.
Fingernails grow at a rate of about 3.5mm per month, while toenails grow at a slower rate of about 1.6mm per month.
The appearance of nails can indicate nutrient deficiencies, drug or alcohol use, illness in other areas of the body, or local injury.
Nails are connected to a richly vascular system in the fingertip. When exposed to air, the water evaporates quickly, causing pain due to the sudden change in pressure.
