!! Amazing facts about the human body !! OK guys, I’m laying before you a few fundamental facts of the human body. Please take the time to go through this really really long post.
I'm sure, by the end you will be in awe of the marvelous body that God / Nature has blessed you with. And I hope you will endeavor to take good care of it.
FACTS ABOUT THE SKELETEAL SYSTEM.
Compact bones such as the thigh's femur can support more weight than granite or reinforced concrete. When pulled end to end - a test to see the tensile strength - bone endures forces of 10,000 to 20,000 pounds per square inch, about the same as pure iron. Squeezed in compression, bone withstands pressure up to 30,000 pounds per square inch. Yet, to keep from damaging the fragile human tissue it connects, bone must be lightweight. The skeleton of a 160-pound body weighs only about 29 pounds. The same framework in steel would be four or five times as heavy. The bones are composed of densely packed mixture of hard mineral crystals-chiefly calcium and phosphorous-and fibrous proteins called collagens. This carefully balanced recipe for bone permits the routine performance of what are in fact magnificent physical stunts. An everyday sit-up for instance burdens the lower spine with as much as pressure as deep-sea divers feel at 570 feet below water. A high jump may load the femur with some 20,000 pounds of stress upon landing; and the bones of the feet must suffer body's weight during each of the 19,000 steps an average person takes each day.
There are 19 bones in each hand, 26 bones in each foot and 29 bones in the skull.
By the time you grow from infancy to adulthood, you will have about 144 fewer bones.
The body grows about a third of an inch every night but shrinks to its original size the next day. Gravity makes the difference. In bed, the cartilage disks of the spine are relieved of gravity's downward pull and expand, adding to body length. A prolonged absence of gravity such as that experienced in space can stretch an astronaut by an inch or two. In old age these Inter vertebral discs get dehydrated and decrease in height, that is what partially contributes to the overall loss of height of an old person.
FACTS ABOUT THE BRAIN, the most enigmatic organ of our body.
The brain reaches its maximum weight by age 20 - approx. 3 pounds and numbers about 100 billion nerve cells. Over the next 60 years, as billions of nerve cells die within the brain, it loses about 3 ounces.
The brain begins to develop after the third week following conception. It arises from a sheet of just 125,000 cells - the neural plate. There after, for remaining eight months of pregnancy 250,000 new neurons appear every minute.
The brain accounts for only 2% of the body weight. But it bathes in 15% of the blood at any given instant and consumes 20% of the nutrition and oxygen. It is the organ that can withstand lack of oxygen for the least amount of time - 3 to 4 minutes only. After this, permanent & usually irreversible damage starts taking place in it.
Messages travel along the nerves as electrical impulses. The largest nerve fibres carry signals at only about 200 miles per hour; others transmits signals slower than 55 miles per hour, at 'leisurely' pace compared to electrons moving at ten thousand miles per second.
The brain receives impulses for perception of pain from the whole body, while the trauma at brain is painless.
About a 100 different chemicals transmit information in the brain and along nerves.
The blood vessels inside the brain have a unique type of wall with cells tightly packed against one another (unlike elsewhere in the body). This is called the 'Blood Brain Barrier'. It protects the brain against the fluctuating composition of blood and minimizes the entry of potentially toxic compounds.
There are 45 miles of nerves in the skin of a human being.
One human brain generates more electrical impulses in a single day than all of the world's telephones put together. This gives a idea of the complex mechanisms by which it controls most of the functions of our body. That is why mental tension / stress can cause multiple disorders.
It is said that an average person uses only about 10% of his brain potential in his lifetime.
AMAZING HAIR FACTS
Hair is the fastest growing tissue (most of which is dead) in the body, second only to bone marrow.
35 meters of hair fibre is produced every day on the average adult scalp.
The average scalp has 100,000 hairs. Redheads have the least at 80,000; brown and black haired persons have about 100,000; and blondes have the most at 120,000.
90% of scalp hairs are growing and 10% are resting.
It is normal to lose 100 hairs per day from the scalp.
You must lose over 50% of your scalp hairs before it is apparent to anyone.
Over 50% of men by age 50 have male pattern hair loss.
40% of women by the time they reach menopause will have female pattern (hereditary) hair loss.
SOME FACTS ABOUT OUR SKIN.
Did you know that the skin is also an 'Organ' of our body, and a very sophisticated organ with numerable functions.
Skin is the largest & heaviest 'organ' of the body. The entire skin of an average adult can weigh upto 20 pounds and covers an area more than 18 sq. ft.
Skin is the interface of our body with the environment and serves many functions crucial to survival, including protection against the elements (including UV rays, mechanical & chemical injury, invasion by infectious agents & prevention of dehydration). The other critical function is thermoregulation, that is to maintain the temperature of the body within the functional range. It functions as a sensory receptor, monitoring diverse environmental stimuli, sends warning messages and takes preventive actions. It also plays and active role in immunological surveillance and excretion.
In 1 square inch of skin there are about 4 yards of nerve fibers, 1300 nerve cells, 100 sweat glands, 3 million cells, twenty feet of blood vessels AND about 20 million bacteria !!
The skin wrinkles if submerged in water for too long because water leaking into the softer cell layer causes them to buckle.
The skin that we actually touch is dead. Cells rise from the bottom of each layer of skin to replace those lost at the top as dead cells are rubbed off or washed away.
The skin is elastic. It stretches to accommodate weight gain and shrinks to your new size as you become slimmer.
Both black and white people have equal numbers of pigment producing cells. It is the genes that determine the rate at which these cells produce pigment.
There are limits to the amount of skin loss through burns that the body can tolerate. Age also affects our capacity to survive major burns. Up to 35 years of age the loss of 75 percent is generally fatal. In the middle age, death is likely to occur after a loss of 50 percent. In old age survival is always doubtful, but a 25 percent loss will probably prove fatal.
The skin cannot lie. Lie detectors, or polygraphs work on the principle that under stress or threat the skin undergoes certain measurable changes caused by hormonal activity.
AMAZING FACTS ON REPRODUCTION
At the moment of ejaculation some 350 million spermatozoa will be deposited around the cervix, yet something less than 100 will ever get near the female egg, of which only 1 is required for pregnancy. .
The female egg is 85000 times bigger than the male sperm.
As many as 50 percent of the total number of spermatozoa will carry some sort of abnormality. The cervix amazingly recognises this fact and rejects them, thus successfully preventing their access to the fertile egg.
Human beings are neither totally male nor female. Each male carries some level of female hormones, and females have a similar male hormone content.
EAR FACTS.
The ear is the organ we not only use for hearing, but more importantly for balance (the primary function). Our world would be disastrous without constant monitoring of our orientation and equilibrium. People with 'vertigo' will vouch for that. The ear consists of three quite separate systems.
The outer ear is the part we all are familiar with- the whorled flap that we call the ear. This exposed part of the ear helps to amplify sound and to assist with the location of the sounds. If a sound is directed at you, you automatically turn your head in order to locate it accurately. This happens because the plotting function of the ear cannot operate if both ears receive the same sound at exactly the same moment. The effectiveness of this function depends on the ability of the brain to measure this minute difference in time. Even with the eyes closed, a person can locate the source of sound to within 3 degrees of the direction: for comparison, an owl can locate sound to within one degree !
The outer ear deflects the sounds into a canal that leads on down to the eardrum, which reacts to sound by vibrating. These vibrations are transmitted to the middle ear where the three tiniest bones in the body are located. Their job is to convert the sound into shorter, more powerful vibrations.
These vibrations enter the inner ear, the cochlea, a coiled chamber partially filled with fluid. Deep inside the cochlea is the organ of corti, sometimes called the real organ of hearing & balance. When stimulated, the hair cells of this organ send impulses directly to the brain & a sound is registered.
Seasickness (or other motion sickness) is caused by the brain misinterpreting the movement of the fluid in the cochlea. This fluid moves constantly in response to the movement of the boat even if you remain perfectly still. The brain thinks that the movement is yours and tries to stabilise the body. The effect and the confusion that follows results in nausea and dizziness.
The Sound energy is converted into mechanical energy when it strikes the eardrum and the bones. This mechanical energy then is tranferred to the fluid of the cochlea where it becomes hydraulic energy. The ripples in the fluid stimulate the hair cells, which on mechanical stimulation, generate numerous electric impulses (electrical energy). These are transmitted via the auditory nerve to the hearing centre in the brain. And finally we perceive sound ! By the way, for transmission of these impulses from a nerve cell to another, some very complex chemical reactions take place. Also there are millions of hair cells but each one deals with only one type of frequency.
Exposure to noise for prolonged periods can harm almost every system in the body.
There are many stories, which would suggest that babies hear and remember sounds they have heard in the womb.
TRULY AMAZING FACTS ABOUT CELLS – the smallest and most fundamental unit of our body.
Every human, i.e. each of us, has spent about half an hour as a single cell in the uterus.
Our cells produce over five tons of protein in a lifetime.
50,000,000 of the cells in your body will die and be replaced with new cells, all while you have been reading this sentence !!!
300 million cells die in the body every minute, but the number of cells remains fairly constant throughout our life. Dead cells are replaced immediately
That means every day more than 300 billion cells die, this consequently means that every day an adult produces 300 billion cells. In childhood (growing age) even more are produced to contribute to the growth of various organs.
Macrophages (white blood cells) in the body consume these billions of dying cells each day.
A neutrophil (a type of white blood cell) can kill 25 bacteria before being killed by its own digestive juices and the accumulated toxins of the bacteria.
In one second, 3 million red blood cells die; the very same number are simultaneously produced. Totally there are about 30 trillion of them circulating in the body.
Stacked one on top of the other, red blood cells obtained from one human being would reach 31,000 miles into the sky.
In just one second, the human body completes about 500 trillion faultless copies of haemoglobin, a protein containing more than 570 amino acids in addition to iron and other components. This is contained in the red blood cell.
More than a trillion platelets patrol the bloodstream repairing rents and tears on the walls of blood vessels to ensure smooth uninterrupted blood flow. Platelets live for only 10 days.
DNA - the molecule that contains the blueprint of our body - can be stretched to 6 feet but lies coiled in a nucleus that is barely 1/2500th of an inch in diameter.
The whole body is made up of small cells. It is like a nation of 100 trillion or so individual cells. Each cell in its turn contains smaller units called as organelles. These cells are busy building the fundamental chemical stuff. The work is previously programmed by the genetic codes present in them. This genetic code is situated within the forty-six tightly packed DNA. It is made up of three billion possible chemical combinations, fifty thousand genes. This is the blue print for reproducing any one of body's two hundred odd different types of specialised cells. All these activities are predestined like that of a programme and are carried out by the cells themselves without direct commands from the brain.
Almost all cells are constantly moving, pulsating and dividing.
Every cell in the body contains enough information to reproduce any other cell in the body & do whatever its specialised function may be. But heart cells only reproduce heart cells, liver cells reproduce only liver cells etc. Cells simply fail to recognise any set of instructions other than the ones necessary to reproduce themselves
Isn't our body marvellous ?! Scientists too date, have not been able to 'produce' a single fully functional cell. All they have been able to do is to 'coax' some cells to divide &/or differentiate into a different type. And they are jubilant about it !!! That is what life is all about. |