The True Nature of Mankind

The Incredible Human Body
Part 2

·  The Mouth
      The average human has about 10,000 taste buds. Those on the tongue are divided into four groups; the tip taste buds sense sweetness; those at the back sense bitterness; the sides sense saltiness and sourness. All the more complex tastes are made up of combinations of the basic four. However, not all taste buds are on the tongue. Some are under the tongue; some are on the inside of the cheeks; some are on the roof of the mouth. Some can even be found on the lips, which are especially sensitive to salt. The sense of taste can detect sweetness in a solution of 1 part sugar to 200 parts water and one gram of salt in 500 liters of water. The average lifespan of a human being's taste bud is 7-10 days. By age sixty, most people have lost half of their taste buds. The strongest muscle in the body is the tongue and every person has a unique tongue print. Pigs, dogs, and some other animals can taste water, but people cannot. Humans don't actually taste water; they taste the chemicals and impurities in the water. 85% of the population can curl their tongue into a tube.
      The tooth is the only part of the human body that can't repair itself and tooth enamel is the hardest of all substances manufactured by the human body. Each tooth contains about 55 miles of canals for a total of over 1700 miles. There are 20 baby teeth and 32 adult teeth. False teeth are often radioactive. Approximately 1 million Americans wear some form of denture; half of these dentures are made of a porcelain compound laced with minute amounts of uranium to stimulate fluorescence. Without the uranium additive, the dentures would be a dull green color when seen under artificial light. If you are right-handed, you will tend to chew your food on the right side of the mouth. If you are left-handed, you will tend to chew your food on the left. A pack-a-day smoker will loose approximately 2 teeth every 10 years.
      It requires the use of 72 muscles to speak a single word. Whispering is more wearing on your voice than a normal speaking tone. Whispering and shouting stretch the vocal cords. A normal person has two true vocal chords and two false vocal chords, which have no direct role in producing sound. The mouth makes one liter of saliva a day and over a lifetime produces enough to fill two swimming pools. Every time you lick a stamp, you're consuming 1/10 of a calorie. Up to the age of six or seven months, a child can breathe and swallow at the same time. An adult cannot do this. Seeing another person yawn makes it likely that you will yawn yourself. Thinking about, even reading about yawning, can cause a yawn.

·  The Skin
      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 create 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.