It used to be thought that, when immersed for a long time, our fingers and toes absorbed water and shrivelled. And that was it. But why do other body parts remain unwrinkled? And why are the wrinkles deeper towards the fingertips?
Surgeons have long known that fingers with nerves severed in accidents do not wrinkle in water, indicating that the wrinkling depends on the nervous system. New studies reveal that the wrinkling is most likely an evolutionary advantage that enables us to grip better in the wet. The wrinkles configure an optimum tread that rapidly removes water from our fingers and toes while increasing the contact surface and traction resistance – rather like the deep treads in tires that are specially designed for wet surfaces. What now needs to be researched is at what point in our evolution this trait appeared – shared, incidentally, with macaques.
It is important to protect the skin from the sun, as it promotes skin ageing and the appearance of blemishes, especially after the age of 40. Do such blemishes affect our health? Is there any way to prevent them?
Time does not forgive. As we get older our skin changes: it becomes increasingly drier and thinner and the number of wrinkles and blemishes increases. These age spots, or solar lentigines, are the result of years of exposure to sunlight or other forms of ultraviolet light (for instance, in tanning booths). They usually occur in the most exposed areas of the skin (the back of the hands, the face, shoulders, forearms and feet). Read More
When we tan, melanocytes (skin cells) produce melanin, a pigment that protects our DNA from the harmful ultraviolet rays of the sun. Scientists have now discovered that the melanocytes also produce a light-sensitive element that accelerates tanning.
UVB rays increase melanin production within a few days of exposure to the sun. UVA rays, however, trigger this process within minutes. The reason is that UVA rays also cause melanocytes to produce rhodopsin, a light-sensitive molecule found in the retina, which, within 24 hours, multiplies the amount of melanin produced by five. This mechanism is our “emergency” defence system against aggression from the sun.
Science years ago confirmed that weight and acne go hand in hand, especially in women. A new study conducted with over 3,500 young people confirms this. This is just one more reason for controlling our weight.
Researchers from several countries have developed a population-based study at the University of Oslo in Norway that confirms the results of previous studies. A body mass index of 25 or more seems to predispose teenage girls to develop acne, although things are not so clear in the case of teenage boys. The reason could be that extra weight increases the production of androgens, the male sex hormone, also produced by the female body, although in smaller quantities.