Head and Brain
The average adult brain weighs just under 3 pounds and is the consistency of tofu.
Although multitaskers are extremely confident in their abilities, evidence exists that shows those people are actually worse at multitasking than most people.
When considering an action that would affect others, teens were less likely than adults to use the medial prefrontal cortex, an area associated with empathy and guilt.
Overall, over time, human brains have shrunk. But, brain size has nothing to do with intellect.
According to one calculation, the average human head contains 456 trillion trillion atoms.
The brain accounts for about 2 percent of body weight, but it uses about 20 percent of the oxygen in our blood and 25 percent of the glucose circulating in our bloodstream.
The old saw that we use just 10 percent of our brainpower isn’t true. We use every part of our brain, even in daily functions.
The brain actually stores different parts of a memory in different locations.
It turns out that both true and false memories activate similar brain regions.
Emotions and Your Body
Babies, who have no sense of social norms or how they are perceived by others, do not blush.
Humans are the only species known to blush, a behavior Darwin called “the most peculiar and the most human of all expressions.”
Optimists live longer and have lower overall death rates than strong pessimists.
No matter your cultural background, if you sob, scream or growl, others are likely to know what you mean, according to a new study.
A well-known side effect of Botox is the inability to fully express emotions. Now research reveals another side effect: the inability to fully feel emotions.
People who are happy are less likely to catch colds and report fewer symptoms of the illness when they are under the weather.
According to one scientist, a “very large part” of our brains is devoted to dealing with immediate threats, but a “very small part” is concerned about planning for the future.
Shivers down the spine even show up in brain scans, according to research at McGill University.
Contrary to popular notions about what is normal or healthy, new research has found that it is OK not to express one’s thoughts and feelings after experiencing a collective trauma, such as a school shooting or terrorist attack.
Squinty eyes and a pinched nose are the facial signals for disgust, the opposite of flared nostrils and widened eyes that reveal fear.
Hair and Nails
A fingernail grows 1/8 inch per month and can grow up to four inches per year.
Your fingernails and hair do not continue to grow after death. It appears they grow, as the skin around them contracts.
A study of 117 male members of the brainy society Mensa (you have to have an IQ of over 140 to join) showed that Mensa members had a tendency to thicker body hair — and the most intelligent had hair on their backs as well as on their chests.
Beards grow faster in spring, possibly indicating a seasonal variation in androgen (male hormone) production.
A recent study suggests that hair keratins evolved first in our bird and reptile ancestors. In the case of the anole lizard, the hair-keratin genes were used for forming claws and possibly their body scales.
Fingernails are, essentially, flattened forms of claws.
Previous studies have shown that human hair discarded from barbershops and hair salons can be a nutrient source for plants when combined with other compost materials.
Curly hair gets less tangled than straight hair.
Poor circulation to the legs (caused by narrowing of the arteries) can eventually lead to loss of leg hair.
If you’ve ever wondered how hair clogs up your pipes so quickly, then consider this: hair cannot be destroyed by cold, change of climate, water, or other natural forces and it is resistant to many kinds of acids and corrosive chemicals.
Bodily Gases and Fluids
The sound you hear when you crack your knuckles is actually the sound of gas bubbles bursting.
Men are sweatier than women, even when you take body size into account.
Sudden hearing loss could occur because of a stroke or severe ear infection. But, in many cases, it’s merely the result of wax buildup.
There are basically two kinds of earwax, wet and dry. Researchers studying earwax genetics say that people with the wet kind generally have more unpleasant armpit odor than people with the dry kind.
Some experts believe that our attempts to hold gas in are an unnatural result of our enclosed lifestyles and the build-up of pressure is responsible for bowel diseases.
In the 1960s, NASA was worried that a build-up of hydrogen from astronauts’ gas might accidentally explode in the spacecraft.
Heat released by the human body in one hour can boil 5 liters of water in one hour.
The human body glows with faint light and faces glow more than the rest of the body.
NASA’s new plan for a water-recovery system recycles not only condensed water vapor and trace contaminants from crew perspiration and respiration, but from urine as well.
Women who smell androstadienone contained in men’s sweat experience increased positive mood, total physiological arousal and sexual arousal, which grows with longer exposure.
Your salivary glands churn out about two to four pints (one to two liters) of spit every day.
Other Body Oddities
Death is one of the side effects of a continued lack of sleep.
Women who slept five or less hours a night were twice as likely to suffer from hypertension than women who slept for seven or more hours.
Most humans in any society (say 70 percent to 95 percent) are right-handed; a minority (say 5 percent to 30 percent) are left-handed, and an indeterminate number of people are probably best described as ambidextrous.
The symptoms of restless legs had been noted by Dr Thomas Willis as far back as 1685.
Recent research has found that varicose veins are more common in men than in women.
The Achilles tendon is the largest tendon in your body, and can withstand more than 1,000 pounds of force, according to the American Academy of Orthopedic Surgeons (AAOS).
The outline or the border of your lips (called the vermilion border) is a special feature of humans only.
Hiccups may be a throwback to 370 million years ago, when our ancient ancestors lived in the ocean and breathed with gills as well as lungs.
Garlic rubbed into the soles of the feet can be detected later in the breath.
Someone who was born blind experiences sounds, smells, and sensations while dreaming, but since the brain possesses no visual information, the dreams are not visual.