Useless Facts On The Human Body
The nose cleans, warms, and humidifies over 500 cubic feet of air every day.
Human eyes are so sensitive that on a clear night when there is no moon, a person sitting on a mountain peak can see a match struck 50 miles a way.
Is impossible to sneeze and keep one's eyes open at the same time.
While reading a page of print the eyes do not move continually across the page. They move in a series of jumps, called “fixations,” from one clump of words to the next.
Two out of three adults in the United States wear glasses at some time.
A sneeze can travel as fast as 100 miles per hour.
As men and women get older their ability to hear high pitched sounds diminishes. The ability to taste sweet foods also decreases with age.
The human nose can detect the odor of artificial musk in such low concentrations as one part musk to 32 billion parts of air.
The easiest sounds for the human ear to hear, and those which carry best when pronounced, are in order, “ah”, “aw,” “eh,” “ee,” and “oo.”
The sound heard by a listener when holding a seashell to his ear does not come from the shell itself. It is the echo of the blood pulsing in the listener's own ear.
A person's nose and ears continue to grow throughout his or her life.
It takes the human eyes an hour to adapt completely to seeing in the dark. Once adapted, however, the eyes are about 100,000 times more sensitive to light than they are in bright sunlight.
The human eyes can perceive more than 1 million simultaneous visual impressions and are able to discriminate among nearly 8 million gradations of color.
The average person's field of vision is 180 degrees.
Sight accounts for 90 to 95 percent of all sensory perceptions.
The pupil of the eye expands as much as 45 percent when a person looks at something pleasing.
One-fourth of the 206 bones in the human body are located in the feet.
Drinking lowers rather than raises the body temperature. There is an illusion of heat because alcohol causes the capillaries to dilate and fill with blood. In very cold weather drinking alcoholic beverages can lead to frostbite.
The strongest bone in the body, the thigh bone, is the hollow. Ounce for ounce it has a greater pressure tolerance and bearing strength than a rod of equivalent size cast in solid steel.
Blue eyes are the most sensitive to light, dark brown the least sensitive.
It takes 17 muscles to smile, 43 muscles to frown.
Type O is the most common blood type in the world. Type AB is the rarest. There is also a subype called A-H, but to date only three people in the world are known to have it.
The substance that human blood resembles most closely in terms of chemical composition is sea water.
There are almost 6 million red blood cells in a cubic millimeter of human blood. The entire body contains about 30 trillion red blood cells. When a person inhales several breaths of carbon monoxide, more than half of the blood's hemoglobin combines with the gas, leaving only half the red blood cells to carry oxygen. This has the same effect on the body as a sudden loss of 50 percent of one's red blood cells. Fifteen million red blood cells are produced and an equal number are destroyed every second.
The average person's hand flexes its finger joints 25 million times during a lifetime.
The average brain comprises 2 percent of a person's total body weight. Yet it requires 25 percent of all oxygen used by the body, as opposed to 12 percent used by the kidneys and 7 percent by the heart.
The body has 70,000 miles of blood vessels. The heart pumps blood through this labyrinth and back again once every minute.
A person breathes 7 quarts of air every minute.
The average person takes from 12 to 18 breaths per minute.
The right lung takes in more air than the left.
The human brain is 80 percent water, more watery than our blood.
The human brain is insensitive to pain. The suffering of a headache comes not from the organ itself but from the nerves and muscles lining it.
Neanderthal man, the first human being in the true sense, had a brain capacity 100 cc larger than modern man's.
The average human heart beats about 100,000 times every 24 hours. In a seventy-two-year lifetime the heart beats more than 2.5 billion times.
A woman's heart beats faster than a man's.
During pregnancy, the uterus expands to 500 times its normal size.
During menstruation, the sensitivity of a woman's middle finger is reduced.
The human tongue taste bitter things with the taste buds toward the back. Salty and pungent flavors are tasted in the middle of the tongue, sweet flavors at the tip.
The average person's total skin covering would weigh about 6 pounds if collected into one mass.
The average woman's thighs are 1 and a half inches larger in circumference than the average man's.
An average man on an average day excretes 2 and a half quarts of sweat.
The palms of the hands and soles of the feet contain more sweat glands than any other part of the body.
A skin graft can be taken only from the skin of one's own body or from the body of an identical twin.
False teeth are often radioactive. Approximately 1 million Americans wear some form of denture; half of these dentures are made of porcelain compound laced with minute amounts of uranium to stimulate fluorescence. Without the uranium addictive the dentures would be a dull green color when seen under artificial light.
For many years after the Battle of Waterloo, dentures known as “Waterloo teeth” were sold throughout Europe. These were actual human teeth extracted from the corpses of soldiers on the Waterloo battlefield. They were especially esteemed among denture wears because most of them came from young, healthy boys.
The older a person gets the less sleep he requires. A child should get from 8 to 9 hours a night. An elderly adult can do well with 4 to 6 hours.
The liver is a gland, not an organ.
The fingernails and the hair are dead. Both are made of a tissue called keratin, which is similar to the dried skin cells that continually flake off the body. Hair and nails, however originate from living cells. Growth occurs at the base, and new cells push the dead hair and nails upward. Then these cells themselves die, to be pushed up and replaced by more from below.
While 7 men in 100 have some form of color blindness, only 1 woman in 1,000 suffers from it. The most common form of color blindness is a red-green deficiency.
The mouth produces a quart of saliva a day.
Human nails and hair do not grow after death. They are simply the last part of the body to disintegrate.
The fingernails grow faster on the hand you favor. If you are right-handed your right fingernails will grow faster; if left-handed, your left. The middle fingernail grows faster than all other nails.
There are 10 trillion living cells in the human body.
Tongue prints are as unique as fingerprints.
The human body has 45 miles of nerves.