Q&A

How many Cells in your body remain the same after 5 years time?

The idea that each cell in our body is replaced every few years is quite popular, but incorrect. Fat cells are replaced at a rate of about 10% per year, but the heart muscle cells are replaced by just 1% per year until the age of 25 years, dropping to 0.5% until the age of 70. Even if you would manage to get to the age of 100 years, you’ll have more than half of heart muscle cells that you were born with. Cerebral cortex neurons and cells in the eye are never replaced and are unable to restore themselves. Although the cells are not completely replaced, they will change and alter. Molecules are continuously exchanged with the surroundings by common metabolic processes. The water in our body is changing almost 3 liters per day. An adult has about 40 liters of water in the body, so that is 7.5% per day. After 2 years, it is statistically unlikely that you have any of the same molecules of water. Calcium in teeth, however, is there forever.

Could a living organism develop an organ that “sees” Radio Waves?

Radio waves are part of the electromagnetic spectrum, along with visible light. But because their wave lengths are larger, radio waves have less energy, so they interact less with the electrons orbiting at the edge of molecules. That is why you cannot perceive radio waves with a light-sensitive pigment, as you do with visible light. At high intensity, radio waves can cause oscillation of the whole molecule they encounter, not only the electrons, thus generating heat. This is also the principle of operation of the microwave oven. The interesting thing is that if you put some species of ants in a microwave device, they will line up in the microwaves direction. They do this in order to minimize thermal effects, not because they “see” radio waves.

Can plants get Cancer?

Yes, plants can develop cancers or tumors, in which plant cells are divided uncontrollably forming various hard lumps. The most common case is the disease caused by Agrobacterium tumefaciens, a bacterium that inserts part of its DNA in the plant’s genome. But these tumors do not invade the surrounding tissues in an aggressive manner and are not transmitted to other parts of the plant (a phenomenon known as metastasis), so they don’t totally fit the definition of human cancer. Part of the explanation is that plants do not have a circulatory system that would allow them to be transported elsewhere. Animal cells specialize during embryonic development, so they can divide into different types of cells. This means that tumor cells invade their surrounding tissue – with other, harmful cells – interfering with the normal functioning of that organ. Plant cells are typically totipotent, meaning that they have the ability to divide forming cells of any kind. So plant tumor includes cells that form correct (normal) multicellular structures, causing the cancerous plant to grow more and often with slightly different shapes compared to the healthy ones. Some plant tumors deactivate the totipotency of cancerous cells, not causing metastases, so therefore not being fatal to the plant.

What is the record of Sleepless nights?

264 hours is the official record of time spent by a man without sleep. In 1964, a student from San Diego named Randy Gardner stayed awake without using any stimulants, for 11 days. He experienced phantom-like sounds and dream/raving states penetrating the waking state, everything scaling up as the days passed. When finally giving in, he slept almost 15 hours continuously. Gardner has not reported any permanent negative effects on his health, in that period

Can you tan under water?

UV-B radiation, i.e. the wavelength of the ultraviolet spectrum that causes burns to the skin, are absorbed by water. Anyway, you need a water depth of a few meters to protect yourself effectively from UV radiation. At two feet deep water, your skin still gets 40% of UV-B radiation. In addition, the cooling effect of water makes you unaware of ongoing skin burn. Therefore, snorkeling enthusiasts often suffer strong back burns, which easily occur in such conditions.

Do you Run Faster while listening to music?

Yes. There are numerous scientific evidence showing how our body reacts to the music rhythm, tending to synchronize the length and frequency of steps and even heartbeat or respiration rate. In one of these specialized studies (published in 2010 in Scandinavian Journal of Medicine and Sports Science), researchers varied the songs tempo with only 10%, without the knowledge of contestants, and found that, in response, cyclists pushed with more force on the pedals and runners increased the steps rate when the rate was increased, although unaware of the differences in music’s bpm (beats per minute) they were listening to.

Can you drink too much water?

Yes. Your digestive system can absorb water nearly as fast as you drink it, but the kidneys of a healthy adult cannot process more than 900 milliliters (30 oz) per hour. So if you drink a liter (~34 oz) of water per hour, the excess will accumulate in cells and in the space between them. The effect will be diluted sodium levels in the blood – a condition called hyponatremia -, which can result in seizures and even cardiac arrest.

Why do we feel hot at 30° C (86° F) if our body temperature is 37° C (98.6° F)?

Not all your body has a temperature of 37° Celsius – it is just the temperature inside the thoracic cavity (the vital organs). Skin, for example, has a much lower temperature because it makes a constant heat exchange between the body and the environment. We are talking about a very important function, because heat – a byproduct of chemical reactions inside cells – would be very harmful if not dissipated continuously. When the ambient temperature reaches 30° C, the temperature gradient between the inside of your body and the skin is much lower, so the heat is not dissipated as fast as it is produced. To compensate, you have to sweat – removing heat through evaporation – to fan (forced convection greenhouse) or drink a hot liquid (yes!). Feeling hot is a warning that “says” you have to do one of three things above. The sensation is controlled by the hypothalamus region of the brain that keeps track of the temperature inside the blood, which comes from the chest cavity.

Are White Clothes really cooler in the summertime?

Yes. Dark materials absorb more heat than light shades, which reflect light. This is a prime factor in the equation. The second one is related to the type of material being used. Natural fibers tend to be cooler than synthetic ones. In high humidity conditions, flax clothes are recommended because this type of natural fibers allow evaporation of moisture from the skin – perspiration or condensation.

Will humans ever evolve to get rid of unnecessary body parts/appendix/vestigial structures?

People don’t usually have useless limbs, or non-seeing eyes, or tails hanging on the ground. In general, each part of a healthy body has a more or less useful role. Toes help us balance, tonsils help fighting infections, appendix acts as a reservoir for intestinal bacteria after infection. 1971 edition of Encyclopaedia Britannica claimed that people have more than 100 rudimentary, unnecessary organs/body parts, but the more we learn, the more we find that they do something useful. But even if wisdom teeth, for example, are useless, evolution does not have much more to say in this direction. Modern dentistry is more convenient. Perhaps in 2000 years, when civilization will probably be ruined by various factors, wisdom teeth will again become a matter of life or death, and natural selection can resume its assiduous work to remove them. The same may happen to other body parts as well.

What is the purpose of Pain?

Pain is a terrible feeling, that you think we might miss out without problems. But this is not the case, as demonstrated by patients with CIPA condition, a strange and extremely rare condition that nullifies the perception of pain. CIPA – an acronym for Congenital Insensitivity to Pain with Anhidrosis – is not a blessing to his victims, which can easily hurt and not being naturally alerted of the problems in their body – such as infection, fracture, failures etc. It may seem paradoxical, but life cannot be fully lived without pain. Pain protects our body through the “army” of sensors spread in the skin, muscles, joints or organs. Pain signals are sent by nerve centers in the spine and brain, which are specialized in interpreting the sensations, through two types of nerves: “rapid” delta fibers respond to sudden, thin stimuli, producing a sensation of acute pain that makes you, for example, to quickly withdraw your hand from a hot stove, and C-fibers which are “slower”, generating chronic, lasting pains, that prevent you from moving or using an hand injured, for example. This happens in order to enable it to cure, or at least to not worsen the wound. A big mystery is the fact that you withdraw your finger from a hot surface faster than perceiving the actual pain, so we wonder why we need to experience the feeling, if the action is done automatically by your nervous system? It certainly would be nicer, but the evolution has aims such as survival and efficiency, so conscious perception of pain should have a strong logical sense – a mystery that remains to be explained by neurologists.

Can science measure Happiness?

Yes. It seems surprising, but when asked to assess their happiness on a scale of 1 to 10, the answers people give are consistent and closely linked to their general behavior. Something is measured somehow, certainly. For example, we know that people in Britain were happier in the ’50s than they are today, suggesting that the attempt to make their lives better in difficult conditions/environments makes people happier than living in abundance by default. Women tend to be happier than men, although more of them have depressions. People with children, especially teenagers, are a bit unhappy, although usually admit that having children fulfills them somehow. But the real challenge arises when trying to distinguish between happiness, health and general welfare, all being in fact related. Then there is a difference between measuring current happiness (or the mood), and measurement of long-term happiness and satisfaction in life. In an interesting way, all this changes with age. Researches from many countries suggest that the chart of happiness is “U”-shaped (or smile-shaped), meaning that middle age is the most unhappy one, in general, and while seniority, paradoxically, is the happiest time of life. For instance, if politicians would want to measure happiness rather than material wealth, there is certainly scientific base to do this.

Why aren’t there any plain blue foods?

Plain blue is a pigment difficult to make in nature. Blue colors are associated with alkaline chemistry, while most plants and animals have a slightly acid metabolism. Few plants with blue flowers have this pigment only in their petals, which often become purple or pink, at different time periods or in different acid soils. Neither currants are blue, but purple or indigo, but white powdery coating makes them appear blue when ripe. Blue color in animal world is obtained rather through small scales that reflect light in the blue spectrum (iridescent), not through natural pigment. Because blue is rare in nature, we have evolved in such a way to not find appetizing, in favor of red fruits.

Why do humans Fall in Love?

Briefly, it happens in order to transmit genes. Evolution gave us big brains and helpless children to be cared for many years, which makes the link between couple members essential for survival of the species. Falling in love is a strategy due to evolution, by which we ensure that we choose a partner as best as we can, given the circumstances, and then to commit to it. Phenylethylamine and dopamine neurotransmitters that induce changes in the brain giving us all those emotions and make us believe that we will love that person forever. Genes can only give general parameters. Why does “X” falls for “Y” is more complicated, and often apparently inexplicable, although similarities, education background, desires and common interests explains much of attractiveness. Falling in love does not last long, but may be the prelude to a long lasting love.

Does Coffee and Tea dehydrate you?

Various experts have warned us long ago that besides the various good effects, tea containing caffeine and coffee act as a strong diuretic, dehydrating by peeing more. This statement still persists despite a number of studies showing that moderate amounts, caffeine acts only as a mild diuretic. One of these studies, published in the European Journal of Applied Phychology in 2004, focused on the effect of tea on hydration for 21 volunteers gathered at Everest Base Camp. Hydration becomes a problem at high altitudes, because more water is lost through the lungs due to pressure and low temperature. Subjects drank four cups of tea in 12 hours, then another day, drank a similar amount of plain warm water for the same time period. It seems that tea had no effect on urination and hydration levels – the only noticeable difference being that it reduced fatigue. Another larger study, published in 2003, concluded that coffee intake did not result in an increase in urination for a 27,936 Norwegian women. There is also a review published in The International Journal of Sport Nutrition and Excercise Metabolism in 2002. It reviewed 10 previous studies that compared diuretic effects of caffeine with water or a placebo. These 10 studies have shown that up to 84% of caffeinated drinks remain in the body after consumption, compared to 81% in case of water. Certainly, tea and coffee are not diuretics threats. Science has shown that, in moderate quantities, they are as hydrating as water.

Why didn’t evolution make Births fun or at least pleasant?

Other mammals do not have the birth problems that we experience for two reasons: Their heads are so large relative to body size and do not walk bipedally (using 2 limbs). To evolve walking on two legs, our ancestors had to change the angle and shape of the pelvis, which reduced the pelvic canal diameter. Natural selection therefore pushes the pelvis in two different directions: To run fast, we need a narrow pelvis, but to give birth easily, we need a large one. This is a known obstetric dilemma, since the human pelvis is a compromise between these two constraints. Our brains grow 3.3 times more from birth to adulthood, compared with 2.5 times in chimpanzees, so humans are born at a much earlier stage of development compared to other animals. But if women would have wider hips than they do now, they would not be able to run. Natural selection was probably more ruthless in eliminating mothers slow at running or with premature babies, than women who are discouraged by the idea of ​​birth because of the pain it causes.

Is sexuality (homosexual/heterosexual) something genetic or acquired?

Studies on identical twins have produced evidence for the existence of a genetic component to homosexuality. But that’s not really a “gay gene“. For example, in 1997, a study at the University of Toronto showed that the more older brothers a man has, the more likely he is to become homosexual, at some point in the future. The inherited component of homosexuality seems to be much weaker in women than in men, but the culture, lifestyle and early sexual experiences are more significant than genetics for both sexes. Certainly, education and culture have a major impact on how people understand and define their own sexuality, but genes may play their smaller part also.

How long is the DNA spiral?

DNA in cells is encapsulated in 46 chromosomes of the nucleus. With a helical (spiral) structure, DNA is super-twisted due to enzymes, to take less space. Try holding a thread at one end, while twisting the other. While whirling, the thread creates spirals of spirals, and finally spiral of spiral of spirals. Our DNA is like a spiral of spiral of spiral of spiral of spirals! This makes the 3 billion base pairs in each cell to fit in a space of only 6 microns. If one would be able to completely stretch the DNA from a cell, it would have almost 2 meters (6.5 feet), while all the DNA in our cells, placed end to end, would be about twice longer than the diameter of the solar system. Isn’t that mind twisting?

Do you get drunk faster if you mix the alcoholic drinks?

Yes, mixing drinks can speed up intoxication of the brain, with all its effects. More so when mixing strong drinks, especially high concentrations of alcohol with carbonated liquids, such as mineral water or coke. Researchers at the University of Manchester have compared the absorption rate of alcohol in people who drank plain vodka to those who consumed vodka half diluted with sodas. Curiously, two thirds of the subjects absorbed alcohol significantly faster when they were given carbonated drinks along with it, reaching the peak alcohol concentration in blood with about 10 minutes quicker. Even more surprising, the same effect was observed when alcohol was diluted with still water. Why this happens remains a mystery.

When does a baby’s heart begin to beat?

Heartbeat is detectable in the middle of the fourth week of pregnancy (or about 24 days of pregnancy). The heart is the first organ to start working in humans, as in all vertebrate embryos. It is assumed that the heart begins pumping nutrients and oxygen to all cells in development, which turn into skin, bones, liver and brain, eliminating waste and carbon dioxide. It’s actually kind of weird to refer to this embryonic structure as “heart” of the child, because at this stage, it’s nothing more than a few vessels that contract to push the blood. These are then reshaped, united and then divided into two pumps with four rooms for your baby to have a heart when it is born.

Is there a neuro-chemical formula of Love?

No. Even if neurochemistry plays an major role in generating and managing emotional reactions, interaction of various specific hormones with our mental state at a specific moment and our memories is too complicated to be reduced to an exact formula. If you inject someone with the adrenaline, the person may feel the physical sensation of anxiety, but to turn a certain emotion, such as fear, anger or sexual arousal, it takes a more complex set of circumstances.

Is it more likely to catch a Cold if we’re cold?

Apparently it is so. Maybe this is where the sickness gets its name of common “cold“. The guilty virus, the rhinovirus, is around us all the time. So getting sick or not depends on your immune system and it’s highly possible that it is affected by temperature. To verify this scientifically, many experiments have been conducted, but the results are rather inconclusive. In an experiment in 2005, 90 people have held the feet in a basin of ice cold water and 20 minutes: after 5 days, almost 30% had cold symptoms. Another group of 90 voluntaries were kept bare feet in empty basins and less than 10% of them caught a cold. It is possible that cold constricts blood vessels in the nose and throat, reducing the efficiency of white blood cells that fight infection. The reaction can be interpreted as a survival strategy. Our immune systems need a lot of energy to run, so in extreme cold conditions it may be wise to use all this energy to heat up. The truth is it’s pointless to try to avoid a virus if you are about to die of hypothermia.

What is the longest living animal?

If sponges count too, then barrel-shaped giant sponge is the winner, with specimens estimated to be over 2,300 years old. Other candidates include North Atlantic quahog clams, which can live over 400 years, and Koi carp who can live over 200 years, although usually dies after just about 20 years. Among the oldest mammals are whales, especially borealis Sei whales. It is believed that the average life span is between 70-80 years, although there is increasing evidence suggesting that they can live over 100 years.

Why don’t Scars disappear as skin changes/exfoliates?

Scars are formed on any wound that heals in more than three or four weeks. The body produces collagen fibers in zig zag form. The normal process of change does not affect skin scars because it involves only the migration of cells from the base of epithelium to the surface. A scar is a separate collagen fiber structure, and epithelial cells simply pass it by.

Why do we Blink at loud noises?

This instinctive reaction is called acoustic blink reflex and is part of the protection mechanism that we all manifest when faced with danger. Loud noises are often, righteously associated with danger, and the eyes are a very valuable and very sensitive part of our body, which is worth protected with priority. Therefore, blinking is a reflex, and not consciously controlled. When they are scared, people blink more often and for a longer time (for example, when subjects are told that they will be put under electric shocks – even if not receiving them). Darkness is another factor that intensifies and lengthens blinking – especially in people who are afraid of the dark. Symmetrically, the reaction is diminished in feelings of relaxation and happiness, while trauma increases it. For example, patients suffering from post-traumatic stress disorder (PTSD), like veterans of the Vietnam War or the Gulf War, have this reflexes of fear more often and at a much higher intensity. Then, medically speaking, alcohol decreases this effect, while amphetamines increase it.

What is the ideal Temperature for Sleeping?

According to a study performed by the University of Lille, France, the ideal temperature for sleep is between 16-19 degrees Celsius (61-66 degrees Fahrenheit)​​ – that is if you sleep wearing pajamas. If you sleep naked, the optimum temperature for sleep increase significantly, to 30-32 degrees Celsius (~86 degrees Fahrenheit).

How do Phobias develop?

Some phobias are exaggerated fears forms inherited through evolution, which all (normal) humans have. For example, people – and some monkeys – instinctive fear of snakes, spiders and rats, which is a biologically normal behavior. These natural fears can then be enhanced or diminished depending on how our parents respond to these stimuli. Emotional learning occurs in other species as well, whose offspring learn from the reactions of their parents. The fact that a phobia seems irrational to the person suffering from it does not make it go away. Other phobias arise from events in life, like that of being chased by a seagull or being trapped in a tight space, but many do not have a clear origin and are difficult to explain. Often they can be improved with proper treatment.

Why don’t people grow Blue or Green Hair?

Human hair color is given by the two types of melanin, the pigment that dictates the color of our skin, too. The bad news for those who would like natural blue hair is that both types are only of dull colors. The most common is Eumelanin, which is dark brown; something more interesting is Feomelanina, which is reddish-yellow, and it is present in large quantities in redheads and blonde hair. As for why we remained only with these two types of pigment, nobody knows for sure, probably because we have evolved our ability to camouflage with the environment, vital to avoid predators in the African savannah, millions of years ago. Who would like his hair to transcend its evolving needs, will need to go to the store and buy more interesting pigments from pharmacies or spas centers.

Why can you physically feel the Emotional pain?

It is because we’re talk about physical pain indeed. Emotions are bodily functions involving the brain, the nervous system and the hormones that control heart rate, breathing, digestion, sleep, and many more. Scans show that physical and emotional pains involve the same areas, including the anterior cingulate cortex. Humans are social beings who have evolved towards cohabitation in groups and taking relationships seriously. So when a friendship breaks or when a loved one leaves us, all these emotional forces come into play.

Why are Names more difficult to remember than Faces?

Long-term memory is managed by parts of the brain that are quite old, in evolutionary terms. And the more primitive a sensory stimulus, the more efficient it is recorded by long-term memory. Faces are a more ancient form of identification than the name. Our brains have evolved to be particularly sensitive to subtle changes in facial features, as the face is a more reliable identification criterion – located in the upper body, facing forward, easy to see, and almost always exposed, unlike the rest of the body which is hidden under clothing. It would be more difficult to remember someone’s shoulders or his navel. Thus, the names are difficult to remember because the brain region responsible with language processing is a very recent evolutionary acquisition.


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