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How Many Muscles Are Used to Smile

postman1 — Sat, 03 Sep 2011 10:58:59 +0000

Many people have heard some version of the saying “it takes X muscles to frown, but only Y muscles to smile,” with X usually being larger than Y, to suggest that it should be easier to smile than frown. The numbers in this saying can vary quite radically, however, and even when one accounts for the different types of smiles, such diversity is a bit suspect; any number between four and 22 seems to be used. In fact, the precise number of muscles used to smile is a bit unclear, although people have certainly conducted extensive research into the matter.

Of the 36 muscles used to create facial expressions, only a fraction are used in smiling. The precise number involved can vary, depending on an assortment of factors. Some people, for example, argue that eye crinkles are part of a genuine smile, and that therefore the muscles involved in this activity should be considered part of the number of muscles required to smile. Researchers have also discovered that people from different areas of the world smile differently, although they may use many of the same muscles.

Different types of smiles have also been extensively documented, ranging from the zygomatic or genuine to the utterly fake. People make smile-like expressions for a variety of reasons and in an assortment of ways, and each requires slightly different muscle movements. By studying pictures of people smiling, some skilled researchers can point out the subtle meaning and variation behind the seemingly friendly facial expression.

Six pairs of muscles appear to be directly involved in smiling: the levator anguli oris, levator labii superioris, orbicularis oculi, risorius, zygomaticus major, and zygomaticus minor. This brings the grand total to 12 muscles most probably used to smile. Most authorities who are familiar with their anatomy seem to settle on this number, with 11 muscles being used to frown. That’s right: in terms of sheer numbers of muscles involved, it is theoretically easier to frown than to smile.

Before one rushes to dispute the saying that it is easier to smile than frown based on this evidence, it is important to be aware that in its resting state, the mouth often approaches a smiling expression, suggesting that minimal effort is required to pull the mouth into a full grin. Furthermore, muscles vary widely in size and strength, so it is entirely possible that people expend less energy in smiling than they do in frowning. Perhaps some intrepid researcher will conduct a detailed study to get to the bottom of the matter.

How Many Neurotransmitters are There

postman1 — Sat, 03 Sep 2011 10:36:53 +0000

A neurotransmitter is a specialized messenger chemical that transfers or sends information from one type of cell to another. Scientists have managed to identify over 100 neurotransmitters in the human brain alone, but evidence suggests we have significantly more than this number. An unfortunate aspect of not being able to identify all neurotransmitter cells is that researchers, especially those developing medications to act on specific messenger cells, can’t always determine why or how medications work or fail to work.

You’re probably familiar with some of the identified neurotransmitter names. These include dopamine, GABA, serotonin, acetylcholine, and norepinephrine. Each of these performs some specific functions in the body. For instance serotonin is indicated in mood stability, emotional response, and temperature control. Acetylcholine is a neurotransmitter that allows for the person to willfully or voluntarily use his or her muscles. While researchers can suggest the possible effects of certain neurotransmitters, they not only haven’t identified them all, but also are nowhere near determining all effects of the messenger cells that have been identified

This is made very clear when people are given medications that should have an effect on a neurotransmitter. A variety of drugs focus on preventing the body from using serotonin too quickly and are called selective serotonin reuptake inhibitors (SSRIs). SSRIs are most commonly used to treat depression, and are helpful in preventing the body from using serotonin too quickly. When this neurotransmitter is in greater supply in the brain it tends to elevate mood, and you’ve likely heard the names of some of the common SSRIs like Prozac®, Zoloft® and Paxil®.

Theoretically, if serotonin were the only neurotransmitter responsible for depression, these medications would treat everyone. Yet many people with depression don’t respond to SSRIs. They may instead respond to medications that act on GABA, dopamine or norepinephrine. Some people have tried all these medications meant to alleviate depression and are still unresponsive to treatment. Failure to respond to treatment suggests we don’t fully understand the role of neurotransmitters in depression, and there may be unidentified messengers that create conditions like depressed or anxious states.

Since we don’t understand the precise mechanism of each neurotransmitter or the true number of all that exist, we also can’t understand how medications, foods, or environmental exposure may affect these chemical messengers. Scientists and researchers must make educated guesses based on what is known, but the plethora of unknown information on these cells equates these theories to trying to playing darts in total darkness. Sometimes the guesses are pretty good; SSRIs for instance are reasonably effective for a lot of people. Other times these theories fail to work, since we’re guessing about what is essentially undiscovered territory, and we have no idea what other effects might be caused by raising or decreasing levels of certain chemicals made by the body.

The mechanism and identification of neurotransmitters remains a fertile area of study in the sciences. If we could know precisely how many of these messengers we have, and exactly how they work, interact with each other, and drive the body, we might be able to effectively develop medications to treat numerous conditions. Until then, educated guesswork is relied upon by science and medicine.

How Many Human Senses are There

postman1 — Sun, 24 Apr 2011 15:59:35 +0000

There are between nine and twenty-one human senses, depending on who you ask, and how they define a sense. It is generally agreed that nine is the minimum. These are touch, taste, smell, sight, hearing, thermoception, nociception, equilibrioception, and proprioception. Hunger and thirst are also sometimes included. Generally, for something to qualify as a sense requires a free-standing sense organ associated with it. A sensory apparatus’ primary source of information should be force data originating from outside the brain.
Thought or intuition is sometimes included as a sense, but this is incorrect. Human thoughts do not take data directly from reality, but rather from the confluence of sensory organs with which they are connected. Sometimes senses are perceived concurrently with each other, for example sounds that have colors associated with them. This phenomenon is called synesthesia, and is relatively rare, though often reported under the influence of hallucinogens or psychedelics
Because the five Aristotlean senses of sight, hearing, taste, touch, and smell — respectively vision, audition, gustation, tactitian, and olfaction — are well-known, let’s take a look at the less popular senses. Despite their infrequent mention, these other senses are very important to our survival and daily functioning.
Equilibrioception is our sense of balance, perceived by the position of fluids in the inner ear. It can be sent off kilter if one spins around in a circle too many times. Having a sensory faculty for the perception of balance is essential for any bipedal species.
Proprioception is the perception of one’s body in space. Like equilibrioception, the data for this sensory faculty comes from within the body rather than from the environment. Proprioception is what a police officer tests when they pull you to the side of the road for suspicions of drunk driving.
Thermoception and nociception were once thought to be simple variations on touch, but they are not. Thermoception is the sensation of heat and nociception is the sensation of pain. Thermoception of external heat sources is quite distinct from the sensation of internal body temperature, which uses a different apparatus. Also, nociception has sometimes been categorized as three senses rather than one, because different receptors perceive pain on the skin, the joints and bones, and the body organs respectively.

How Much Radiation can the Human Body Safely Receive

postman1 — Sun, 24 Apr 2011 09:55:05 +0000

Since the advent of nuclear energy and space travel, humans have been exposed to radiation more frequently and it has become a hot topic. There are various different things that we call “radiation”, but the type that damages humans is composed of either electromagnetic waves or atomic nuclei, which do their damage through ionization – knocking the electrons in our atoms off their orbits. If a human is exposed to too much radiation, it can cause damage, sometimes making it impossible for certain cells to continue replacing themselves, which can be fatal.
Radiation absorbed by tissue is measured in rads, where a rad is a hundredth of a joule per kilogram of tissue. A gray, a hundred times this value, is the more recently used International System of Units (SI) equivalent. Rads and grays only measure the physical intensity of the radiation, which does not accurately correlate to “damage done”.
By multiplying the intensity by two variables, Q and N, a more accurate “damage done” unit is derived, the sievert (Sv), which is a hundred times the rem. Both units are used to measure the same thing, and though the latter term is more commonly used, the former is more scientifically proper. The rad converts to the rem, while the gray converts to the sievert.
The variable Q changes based on the nature of the radiation. Photons, a relatively light form of radiation, have a Q of 1, while atomic nuclei, a relatively heavy form of radiation, have a Q of 20. The variable N changes based on the relevant tissue and species. Humans are more sensitive than most animals to radiation, therefore holding the relatively high N value of 1. A virus may have an N value a hundred or even ten thousand times smaller than this. Because of variations based on these two values, a given gray of radiation can do a wide range of actual damage, measured in sieverts.
There is a small amount of ambient background radiation everywhere on earth, which we and all life on this planet are adapted to deal with. This varies significantly based on location, but a good average is 2.4 millisieverts (mSv) per year. In space, the radiation level may be dozens or hundreds of times this value.
Radiation today is mainly released in abrupt exposures, so we mostly know about the effects of absorbing a given quantity of radiation in a very short time frame. They are as follows:
At about half a sievert to a sievert, the effects of radiation sickness can be felt. A portion of the red blood cells are temporarily wiped out, and sperm in the testes are deprived of their ability to fertilize an egg until they are recreated. Mild headache and loss of focus temporarily occur.
n radiation exposures ranging from about one sievert to two sieverts, permanent effects, or mild radiation poisoning, begin. Most people experience mild nausea, sometimes accompanied by vomiting, which lasts for about a day. A feeling of general illness persists for a week or two.
For levels of radiation more intense than this, bad things happen. For every additional sievert past one, the chance of death within 30 days increases by about 15%, adding to a base rate of around 10%. This means that about 25% of all people die within 30 days of exposure to two sieverts, around 40% of people die after exposure to three sieverts, and about 55% of people die after exposure to four sieverts. At six sieverts, the death rate is 90%, which increases quickly to 100%. The primary causes of death are internal bleeding or immune system failure that rapidly gives way to lethal infection. Hair is lost, people are rendered sterile, bone marrow is destroyed, and recovery can take years and may never be complete.

How Many Hours Does the Ovulation Period Last

postman1 — Sat, 23 Apr 2011 22:43:40 +0000

he ovulation period lasts 24 to 48 hours. That seems like a very narrow window to get pregnant, but it’s important to remember that sperm can live 3 to 5 days in the woman’s body.
So while your chances of getting pregnant are much better if you have sexual intercourse in the day or two before ovulation, it is possible to get pregnant from sexual intercourse that occurred up to five days before ovulation.
Some women with PCOS experience multiple patches of fertile cervical mucus throughout their menstrual cycles. That doesn’t mean their ovulation period is longer, but instead, the multiple patches are caused by abnormally elevated levels of LH.
If this is a problem for you, the last batch of days in a given cycle that you have fertile cervical mucus is the batch of days that most likely preceded your ovulation period. For example, if you detected fertile cervical mucus on days 8, 9, 12, 13, 16, 17, and 18 of your menstrual cycle, you can assume that sex on days 17 and 18 were the most likely to help you get pregnant.

How Many Eggs Dose a Woman Have

postman1 — Sat, 23 Apr 2011 22:24:45 +0000

Unlike men, who produce new sperm daily throughout most of their lifetime, women are born with all their eggs in one – okay, two baskets (ovaries). To be more precise, a woman is born with about one to two million immature eggs, or follicles, in her ovaries.
Throughout her life, the vast majority of follicles will die through a process known as atresia. Atresia begins at birth and continues throughout the course of the woman’s reproductive life. When a woman reaches puberty and starts to menstruate, only about 400,000 follicles remain. With each menstrual cycle, a thousand follicles are lost and only one lucky little follicle will actually mature into an ovum (egg), which is released into the fallopian tube, kicking off ovulation. That means that of the one to two million follicles, only about 400 will ever mature.
Relatively little or no follicles remain at menopause, which usually begins when a woman is between 48-55 years of age. The remaining follicles are unlikely to mature and become viable eggs because of the hormonal changes that come along with menopause.

How Many People Die Each Year From Peanut Allergies

postman1 — Thu, 21 Apr 2011 20:22:00 +0000

Peanut allergies are the body’s overreaction to certain proteins found in peanuts. The immune system’s response to these allergens is to trigger an antibody, which then triggers other chemicals. One of the scariest results of these chemicals is the chance for anaphylaxis, which is a potentially fatal condition in which sufferers have trouble breathing because of constricted airways, experience a sudden and drastic drop in blood pressure, have an increased pulse rate, and sometimes even pass out.
Estimates say that in the United States, thousands of people visit the emergency room annually because of allergic reactions to food. Somewhere around 150 to 200 people die in the U.S. each year because of food allergies. It’s estimated that around 50 percent to 62 percent of those fatal cases of anaphylaxis were caused by peanut allergies. Meanwhile, around 10 people in the United Kingdom die each year because of food allergies. However, these figures are not completely reliable, in part because allergic deaths aren’t considered reportable events.
Although the number of people who die annually from peanut allergies is in the low hundreds at most, peanuts have gotten a reputation for being particularly deadly. While some people call peanut allergies an epidemic, others say the situation has been blown out of proportion. For example, Professor Nicolas Christakis of Harvard Medical School told the BBC that there was “a gross overreaction to the magnitude of the threat.” He even said that the fear of peanuts had led to a situation resembling mass psychogenic illness — once known as epidemic hysteria. Meanwhile, the “Journal of Allergy and Clinical Immunology” notes that the “epidemic” of peanut allergies only applies to the U.S. In France, the rate of peanut allergy is somewhere between .3 percent and .75 percent; Denmark is lower at .2 to .4 percent; and in Israel the rate of peanut allergy is around .04 percent.

How Many Ribs Does an Adult Human Have

postman1 — Thu, 21 Apr 2011 19:46:39 +0000

Humans have 24 ribs (12 pairs). The first seven sets of ribs, known as “true ribs”, are directly attached to the sternum through the costal cartilage. Rib 1 is unique and harder to distinguish from other ribs. It is a short, flat, C-shaped bone. The vertebral attachment can be found just below the neck and the majority of this bone can be found above the level of the clavicle. Ribs 2 through 7 have a more traditional appearance. The following five sets are known as “false ribs”, three of these sharing a common cartilaginous connection to the sternum, while the last two (eleventh and twelfth ribs) are termed floating ribs (costae fluitantes) or vertebral ribs. They are attached to the vertebrae only, and not to the sternum or cartilage coming off of the sternum. Some people are missing one of the two pairs of floating ribs, while others have a third pair. Rib removal is the surgical excision of ribs for therapeutic or cosmetic reasons.
In general, human ribs increase in length from ribs 1 through 7 and decrease in length again through rib 12. Along with this change in size, the ribs become progressively oblique (slanted) from ribs 1 through 9, then less slanted through rib 12.
The ribcage is separated from the lower abdomen by the thoracic diaphragm which controls breathing. When the diaphragm contracts, the ribcage and thoracic cavity are expanded, reducing intra-thoracic pressure and drawing air into the lungs.

How Many Calories do You Burn by Having Sexual Activities

postman1 — Thu, 21 Apr 2011 19:27:53 +0000

Sex—and smooching and snuggling and everything else on the spectrum—is great for your relationship and happiness, but intimate time with your sweetie is also terrific for your physical health. Not only does that “loving feeling” get your heart rate up, it can burn some serious calories, too!
Remember how, when you were first dating, you’d start locking lips and 30 minutes later you’d come up for air? See if you can get into that groove again, say experts. Not only is smooching a great way to show affection and improve your bond as a couple, it can also help you burn fat. “If the kissing is vigorous and involves some petting, it could be even closer to 90 calories burned in an hour,” says Jaiya Kinzbach, a Los Angeles–based sexologist and the author of Red Hot Touch. Try her technique for turning kissing into an honest-to-goodness workout session: “Kiss in unusual positions,” she recommends. “Have the guy on his back and do ‘plank pose’ or a push-up on top of him, coming down to kiss him and then pushing back up. Push-ups burn 171 calories in 30 minutes.”
You probably don’t put much thought into undressing when you’re getting intimate with your partner, but an Italian researcher looked into the matter and found that the mere act of taking one’s clothes off burns about 8 to 10 calories. Even more fascinating, the researcher reportedly found that a man attempting to remove a bra with his mouth burns as many as 80 calories. here’s what is: By upping the energy you put into undressing, you can burn some extra calories. Don’t just strip down in seconds, says Kinzbach; instead, “draw it out and make it part of your foreplay, while getting a great a workout going
Here’s a stat you don’t hear every day: Being on the giving end of oral sex may be just as effective as a quick stint on the elliptical machine. But if you want to take your calorie-burning to the next level, Kinzbach recommends this calorie-blasting technique: push-ups (yes, in the act!). “Also you can do a little yoga, suggests Kinzbach. “Try plank position into downward facing dog, and back into plank where you can lower down and do some oral stimulation.” Tack on 71 extra calories blasted when you do push-ups, and 35 additional calories by mixing in some yoga
A sizzling clothes-on make-out session with the man you love may be the most intense caloric blaster yet. Why? Anticipation, says Dr. Carle, can get your heart rate going. “It gives way to heavy breathing, which gives way to a great calorie burn,” she explains. But you can still maximize the workout by making it hotter and sweatier! “The hotter the room—think Bikram (a.k.a. “hot”) yoga—and the sweatier the make-out session, the more calories you burn,” adds Kinzbach. Also, try rolling around on the bed or changing your scenery. “Make it playful and erotic and you have a great combination for a pleasurable workout.”

How Many Natural Teeth are you Supposed to Have

postman1 — Thu, 21 Apr 2011 12:38:07 +0000

Most adults have 32 teeth, including one’s “wisdom” teeth. Many people are not born with all of their wisdom teeth, particularly if one or both parents were missing some of them. In addition, some people lack other teeth from birth, and many people have extra teeth – it’s very dependent on the individual. It’s not at all uncommon for wisdom teeth to come in as late as the mid- to late 20s; however, they will usually show up as partially formed “buds” on an x-ray in the mid-teens.