The largest and heaviest organ is the skin, with a surface area of about 25 square feet and a weight of about 6 pounds. The epidermis, the outermost layer of the skin, sheds itself at a rate of about a million cells every 40 minutes. Humans shed about 600,000 particles of skin every hour, about 1.5 pounds a year, and grow all new outer skin cells about every 27 days, almost 1.000 new skins a lifetime. By 70 years of age, an average person will have lost 105 pounds of skin. Floor dust contains 90% dead skin.
The skin is only about as deep as the tip of a ballpoint pen but the sense of touch is more refined than any device ever created. A human can detect the wing of a bee falling on their cheek from a height of one centimeter. There are 45 miles of nerves in the skin of a human being. When we touch something, we send a message to our brain at 125 mph. In one square inch of skin we have nine feet of blood vessels, 600 pain sensors, four yards of nerve fibers, 1300 nerve cells, 9000 nerve endings, 36 heat sensors, 75 pressure sensors, 650 sweat glands, 60,000 pigment cells, 100 sweat glands, 3 million cells, and an average of 32 million bacteria. Your fingernails grow four times as fast as your toenails.
Perspiration is odorless; it is the bacteria on the skin that creates an odor. The skin of the armpits can harbor up to 516,000 bacteria per square inch, while drier areas, such as the forearm, have only about 13,000 bacteria per square inch. There are about 2 million sweat glands in the average human body. The average adult loses 540 calories with every liter of sweat and men sweat about 40% more than women. There are approximately 250,000 sweat glands in your feet and they sweat as much as 8 ounces of moisture per day. You perspire a total of 1.5 pints a day.
The tips of fingers and the soles of feet are covered by a thick, tough layer of skin called the stratum corneum. Identical twins do not have identical fingerprints. No two sets of prints are alike, including those of identical twins. The fingerprints of koala bears are virtually indistinguishable from those of humans, so much so that they could be confused at a crime scene. Humans are the only primates that don’t have pigment in the palms of their hands. A simple, moderately severe sunburn damages the blood vessels to such an extent that it takes four to fifteen months for them to return to their normal condition. First-degree burns affect only the very top layers of the skin; second-degree burns are midway through the skin’s thickness. Third-degree burns penetrate and damage the entire thickness of the skin. Varicose veins are stretched, dilated veins whose valves do not work properly.
· The Bones
The average human body has 208 bones, 54 are in the hands; 52 are in the feet, 28 above the neck, 6 are in the ears, and 22 are in the skull. The skeleton of an average 160-pound body weighs about 29 pounds. A newborn baby has 330 but as the child grows, some of the bones join together to give fewer bones in total. Babies are born without kneecaps. They don’t appear until the child reaches 2-6 years of age. The longest human bone is the femur or thighbone, which is 48 cm. long. It is so strong that it can support 30 times the weight of a man! The strongest bone in the body, the thighbone, is hollow. Ounce for ounce, it has a greater pressure tolerance and bearing strength than a rod of equivalent size made of cast steel.
The mineral content, porosity, and general makeup of human bone is nearly identical to some species of South Pacific coral. The two are so alike that plastic surgeons are using the coral to replace lost human bone in facial reconstructions. The body has over 100 joints. The average person’s hand flexes its finger joints 25 million times during a lifetime. Most people’s legs are slightly different lengths. Giraffes and humans have the same number of vertebrae in their necks. The pop you get when you crack your knuckles is actually a bubble of gas bursting generated by imploding synobial fluid. The “funny bone” is not a bone it is a nerve. The structural plans of a whale’s, a dog’s, a bird’s, and a man’s ‘arm’ are exactly the same.
· The Muscles
The human body has over 600 muscles accounting for 40% of the body’s weight and 1/3 of those muscles are used just to blink the eyes. The strongest muscle in the body is the tongue. Jaw muscles can provide about 200 pounds of force for chewing. To focus the eye, muscles move 100,000 times a day. To give the leg muscle the same amount of exercise would require a 50-mile walk. It takes 17 muscles to smile, 43 to frown, and every 2000 frowns creates one wrinkle. The longest name for a muscle is: Levator Labii Superioris Alaeque Nasi. It is a two-inch muscle that elevates the tip of the mouth. The simple act of walking requires the use of 200 muscles in the human body. The smallest human muscle is in the ear, which is a little over 1 mm long. If all the muscles in an average body were made into one muscle, it could produce about 2,000 tons force. The longest muscle in the human body is the sartorius. This narrow muscle of the thigh passes obliquely across the front of the thigh and helps rotate the leg to the position assumed in sitting cross-legged. No one truly has double joints. Contortionists are actually able to stretch the fibrous tissues known as ligaments. Ligaments hold organs in place and fasten bones together. Ligaments normally restrict the movements of certain joints, but some folks find that their ligaments are more flexible than others. Between the time of death and the onset of rigor mortis in a human body, the contraction of the muscles can cause the body to turn over on its side.
The body gives off the amount of heat equivalent to a 100-watt light bulb and overall produces 25,000 BTUs. 26 calories are burned in a one-minute kiss and banging ones head against a wall will use 150 calories an hour. In a lifetime, the average US resident eats more than 50 tons of food and drinks more than 13,000 gallons of liquid. This includes 8 spiders. 75% of your body heat escapes through your head. The body uses 48 kg of ATP a day (ATP is the energy the body produces during cellular respiration). A person will die from total lack of sleep sooner than from starvation. Death will occur about 10 days without sleep, while starvation takes a few weeks. Small animals, like bats and shrews, consume up to one and one half times their body weight in food every day. For an adult male, this would be like eating 1,000 quarter-pound cheeseburgers a day, or about 50 Thanksgiving dinners a day. Moderate dancing burns 250 to 300 calories an hour. Twenty minutes of moderate dancing will elevate heart rate up to aerobic levels. One study found polkas, swing dancing, and waltzes to be particularly effective for weight loss. If you yelled for 8 years, 7 months and 6 days, you would have produced enough sound energy to heat one cup of coffee. Every human body is naturally radioactive. Our tissues contain traces of the radioactive isotopes Potassium-40 and Carbon-14, which are absorbed by all living organisms from the environment. Every person has nearly 400,000 radioactive atoms disintegrating into other atoms in his or her body each second. Each body cell contains an average of 90 trillion atoms, 225 million times that 400,000 disintegrating. Women burn fat more slowly than men, by a rate of about 50 calories a day. Laughing is aerobic. It provides a workout for the diaphragm and increases the body’s ability to use oxygen. Laughing lowers levels of stress hormones and strengthens the immune system. Six-year-olds laugh an average of 300 times a day. Adults only laugh 15 to 100 times a day. Most deaths in a hospital are between the times of 4pm and 6pm, the time when the human body is at its weakest. There are 110 calories consumed during an hour of typing, only 30 more than those used while sleeping.
· Organs and Glands
Even if the stomach, the spleen, 75 percent of the liver, 80 percent of the intestines, one kidney, one lung, and virtually every organ from the pelvic and groin area are removed, the human body can still survive. The average Human bladder can hold 13 ounces of liquid. There are 35 million digestive glands in the stomach. The pituitary gland, responsible for producing the hormone that regulates growth, is only the size of a pea and weighs little more than a small paper clip. The liver is often called the body’s chemical factory and performs over 500 functions. If 80 percent of your liver were to be removed, the remaining part would continue to function. Within a few months, the liver would have reconstituted itself to its original size. The liver is a gland, not an organ. The liver stretches across almost the width of the body, occupying a space about the size of a football. It weighs more than 3 lbs. The kidney consists of over 1 million little tubes, and the total length of the tubes in both kidneys runs to about forty miles.
The body contains hydrogen, copper, zinc, cobalt, calcium, manganese, phosphates, nickel, sulfur, potassium, carbon iron, and silicon. The average human body contains enough: sulfur to kill all fleas on an average dog, carbon to make 900 pencils, potassium to fire a toy cannon, fat to make 7 bars of soap, phosphorus to make 2,200 match heads, water to fill a ten-gallon tank, and enough iron to make a 3 inch nail. The hydrochloric acid of the human digestive process is so strong a corrosive that it easily can eat its way through the iron of an automobile body. Yet, it doesn’t endanger the stomach’s sticky mucus walls. Smart people have more zinc in their hair. The body’s daily requirement of vitamins and minerals is less than a thimbleful.
The human body consists of about 60 trillion cells, and each cell has about 10,000 times as many molecules as the Milky Way has stars. Except for your brain cells, 50,000 of the cells in your body will have died and been replaced with others, all while you have been reading this sentence. Three hundred million cells die in the human body every minute. The largest cell in the human body is the female reproductive cell, the ovum. The smallest is the male sperm. The average adult has between 40 and 50 billion fat cells.
All of the DNA in an adult human body could fit inside one ice cube, but if unwound, stretched out and joined end to end, it would reach from the earth to the sun and back again more than 400 times. Scientists estimate that they could fill a 1,000-volume encyclopedia with the coded instructions in the DNA of a single human cell if the instructions could be translated to English.
If you were freeze dried, like coffee, 90% of your weight would be the real you and 10% would be the little critters that call your body their home. If all of the spaces between the nucleus’s of the atoms making up an average human body were removed, the person would be the size of half a flea. However, they would still weigh the same.
Asparagus Urine: The first suspect was proposed in 1891. It was proposed that as your body metabolizes asparagus, it produces a smelly chemical, a metabolite called methanethiol, which your discriminating kidneys see fit to dump into the bladder. Other culprits suspected are S-Methyl Thioesters, or six sulfur-containing compounds. Research says just 22 percent of survey respondents experience asparagus urine but the problem proved to be one not of producing the stinky urine but of being able to sniff it out.
The average human body is worth about 25 dollars.
People are the only animals in the world who cry tears.
Undertakers report that human bodies do not deteriorate as quickly as they used to. The reason, they believe, is that the modern diet contains so many preservatives that these chemicals tend to prevent the body from decomposing too rapidly after death.
In the average lifetime, a person will walk the equivalent of 5 times around the equator.
The average adult stands 0.4 inch (1 cm) taller in the morning than in the evening because the cartilage in the spine compresses during the day.
The thumb is such a major player in the human body that it has a special section reserved for it in the brain that is separate from the area that controls the fingers.