Why do we have different skin colours?
The colour of a person's skin depends on his environment. In regions with abundant sunlight, a dark skin colour is necessary to provide protection against the harmful UV rays, Light-skinned people in north Europe, where there is very little sunlight, do not need this protection. UV rays are not always harmful they are needed for the formation of vitamin D, which the body needs for building bones. The darker the skin, the less sunlight can enter the skin and vitamin D formation is reduced. A dark skin may, therefore, result in Vitamin D deficiency in areas where there is not much sunlight.
The colour of a person's skin depends on his environment. In regions with abundant sunlight, a dark skin colour is necessary to provide protection against the harmful UV rays, Light-skinned people in north Europe, where there is very little sunlight, do not need this protection. UV rays are not always harmful they are needed for the formation of vitamin D, which the body needs for building bones. The darker the skin, the less sunlight can enter the skin and vitamin D formation is reduced. A dark skin may, therefore, result in Vitamin D deficiency in areas where there is not much sunlight.
What does the skin do?
Our skin is the largest, heaviest, and the most versatile organ. The skin forms the outer covering of our bodies. The colour of the skin and hair determines our appearance. Without the skin, we would not have any protection against UV rays, injuries, and germs invading from outside. Our sense of touch would not work without it. The skin reacts to the outside stimuli and becomes red, brown, or gets goose pimples. Each person has a unique set of fingerprints, and police can often catch criminals by matching their fingerprints.
Our skin is the largest, heaviest, and the most versatile organ. The skin forms the outer covering of our bodies. The colour of the skin and hair determines our appearance. Without the skin, we would not have any protection against UV rays, injuries, and germs invading from outside. Our sense of touch would not work without it. The skin reacts to the outside stimuli and becomes red, brown, or gets goose pimples. Each person has a unique set of fingerprints, and police can often catch criminals by matching their fingerprints.
Why does the skin get tanned in the sun?
In the summers, our skin is often exposed to UV radiation from strong sun that can damage the skin. A pigment, called melanin, is produced in the skin to protect against the harmful radiations from the sun. The more this pigment is produced the darker, i e., more tanned, is the skin and the higher is the protection against sunburn. That is why, many light-skinned people get sunburnt very quickly. Sunburn always means damage to the skin. Even when the skin has apparently recovered from the burn, it remains damaged from inside and there is always a high risk of getting skin cancer later.
In the summers, our skin is often exposed to UV radiation from strong sun that can damage the skin. A pigment, called melanin, is produced in the skin to protect against the harmful radiations from the sun. The more this pigment is produced the darker, i e., more tanned, is the skin and the higher is the protection against sunburn. That is why, many light-skinned people get sunburnt very quickly. Sunburn always means damage to the skin. Even when the skin has apparently recovered from the burn, it remains damaged from inside and there is always a high risk of getting skin cancer later.
Why do we get goose pimples?
Goose pimples help in regulating the body temperature. When we are exposed to cold temperature or get scared, our body hairs stand up so that the air between them can form an insulating layer. Each hair is permanently anchored to the skin with its root. Small muscles are present at these roots, which contract in case of cold or fear. This is visible on the skin as small bumps. The contraction of the muscles also produces heat in the body. This was an excellent warm-up device for our thickly haired carly ancestors who did not wear clothes.
Goose pimples help in regulating the body temperature. When we are exposed to cold temperature or get scared, our body hairs stand up so that the air between them can form an insulating layer. Each hair is permanently anchored to the skin with its root. Small muscles are present at these roots, which contract in case of cold or fear. This is visible on the skin as small bumps. The contraction of the muscles also produces heat in the body. This was an excellent warm-up device for our thickly haired carly ancestors who did not wear clothes.
Why can't we tickle ourselves?
The skin, as a sense organ, perceives all kinds of touch sensations as signals. These signals are sent to the brain, are interpreted, and the body reacts accordingly. The brain can
differentiate between the touch stimuli that we create ourselves and the stimuli given by others. If we try to tickle ourselves, our brain anticipates this type of touch from our hands and prepares itself for it. Since the element of unexpectedness is missing, the body does not respond the same way as i would if someone else were to tickle us.
The skin, as a sense organ, perceives all kinds of touch sensations as signals. These signals are sent to the brain, are interpreted, and the body reacts accordingly. The brain can
differentiate between the touch stimuli that we create ourselves and the stimuli given by others. If we try to tickle ourselves, our brain anticipates this type of touch from our hands and prepares itself for it. Since the element of unexpectedness is missing, the body does not respond the same way as i would if someone else were to tickle us.
How can people be identified with the help of fingerprints?
Just as each human being is unique, his grooved fingertips are also unique. Even identical twins do not have the same patterns of grooves on their fingertips. Minor cuts and some skin diseases may cause temporary changes in the patterns, but on healing, the same pattern appears. Since 1901, police have used this knowledge to compare the fingerprints found at a crime site with those of the suspects. In early days, this comparison was done manually and used to be very cumbersome and time-consuming. Today, fingerprints are matched by the computer in a fraction of the time used earlier.
Just as each human being is unique, his grooved fingertips are also unique. Even identical twins do not have the same patterns of grooves on their fingertips. Minor cuts and some skin diseases may cause temporary changes in the patterns, but on healing, the same pattern appears. Since 1901, police have used this knowledge to compare the fingerprints found at a crime site with those of the suspects. In early days, this comparison was done manually and used to be very cumbersome and time-consuming. Today, fingerprints are matched by the computer in a fraction of the time used earlier.
