The Marvel of
The stunning marvel of our Lord's workmanship -- "without Him was not anything made that was made" (Jn. 1:3) -- perhaps reaches its apex in the human body. "I am fearfully and wonderfully made" (Psa. 135:14); and when are added the depthless mystery of the soul and of the spirit, we are struck speechless.
The heart beats seventy times a minute, 4,200 times an hour, 100,800 times a day, 36,792,000 times a year, 2,565,440,000 times in three-score and ten years, and at each beat two and a half ounces of blood are thrown out of it, one hundred and seventy-five ounces a minute, six hundred and fifty-six pounds an hour, seven and three-fourths tons a day. All the blood in the body passes through the heart in 3 minutes.
The lungs will contain about one gallon of air at their usual degree of inflation. We breathe on an average 1,200 times an hour, inhale six hundred gallons of air, or 24,000 a day. The aggregate surface of the air cells of the lungs exceeds 20,000 square inches, an area very nearly equal to the floor of a room twelve feet square.
The average weight of the brain of an adult male is three pounds and eight ounces, of a female two pounds and four ounces. The nerves are all connected with it, directly or by the spinal marrow. These nerves, together with their branches and minute ramifications, probably exceed 10,000,000 in number, forming a bodyguard outnumbering by far the greatest army ever marshaled!
The skin is composed of three layers and varies from one-fourth to one-eighth of an inch in thickness. The atmospheric pressure being about fourteen pounds to the square inch, a person of medium size is subjected to a pressure of 40,000 lbs. Each square inch of skin contains 35,000 sweating tubes or perspiratory pores, each of which may be likened to a little drain pipe one-fourth of an inch long, making an aggregate length of the entire surface of the body of 201,165 feet, or a tile ditch for draining the body almost forty miles long.
The human body is a marvel of mechanical efficiency and adaptability. Like many other machines, it derives its energy from carbon. Coal or oil burning engines get their carbon from coal or oil. But these fuels come originally from plants. Man also gets his carbon from plants, either directly or through the meat of an animal which has eaten plants or has eaten some other animal which has eaten plants. The body, like an engine, takes in oxygen, combines it with the carbon, and exhales carbon dioxide. The energy resulting from the combustion is the energy at our disposal for everything we do.
Because of this oxidation process going on within him, man is a kind of walking furnace. The average human body dissipates about 2,500 calories daily -- enough energy to boil 25 pots of coffee. The oxidation also provides us with heat -- which is a form of energy. A remarkable temperature regulation system keeps the body heat at an average of about 98.6 F. throughout our lives, summer and winter, except when a higher temperature is needed to combat disease.
The regulation of the temperature of the blood stream is accomplished through a delicate control center in the brain. From this center, nervous signals are sent throughout the body asking for an increase or decrease of temperature. If the temperature drops, oxidation is increased and the blood vessels of the skin contract, so that less heat is lost by radiation. The skin glands secrete a fatty substance, the hair of the skin stands erect, resulting in a layer of dead air which acts as an insulation layer.
If the blood temperature becomes too high, signals are sent from the control center for the oxidation to be decreased. The blood vessels of the skin dilate, so that more blood passes through and perspiration takes place. The moisture thus evaporated cools the skin surface and the body.
This remarkable system can -- for a limited time -- prevent our body temperature from rising, even in heat that will fry a steak. A man has actually withstood a temperature of 262 degrees for fifteen minutes. A steak was fried in the same enclosure during the time he was in it, yet close to his skin, almost normal body temperature was measured.
The body is an intricate electronic device, far more complicated than any which man has ever built. The human brain is made up of something like 10 million nerve cells, or neurons. Each neuron is a battery-powered device operating at a potential of 0.07 volts.
If man were to make an electronic equivalent of the human brain, it would need a very large building to house it, and all the electricity generated at Niagara Falls to operate it.
The nervous system is a telephone system by which the brain is kept informed of what goes on around us. It is estimated that each of our eyes has 130,000,000 rods and 7,000,000 cones which are the sensory terminals of sight. These are connected to the brain by over 300,000 separate "telephone" lines. When we look at something, the thing we see is broken down by these millions of sensory points, and the graduations of light and shade and color of each incremental area are sent to the brain as separate signals. There they are rearranged, in some way yet unknown to us, to give the impression of visualizing the whole scene.
In television, each tiny elemental area of the screen is connected to the receiver for only about 1-250,000th of the time. In the human eye, information is sent to the brain from all areas of the scene simultaneously. Some of the early television systems proposed to use the method which the eye uses, but the system was so bulky, even to transmit a very poor image, that it was abandoned.
To carry signals from the ear to the brain, something like 150,000 separate conductors lead from each ear, each insulated from the others. These signals are picked up by delicate probes on the brain, amplified by sensitive amplifiers and reproduced on a loudspeaker. These electrical signals sent to the brain, in some unknown way give us the sensation of hearing.(World Science Review)
The Human Body
In 24 hours the average adult accomplishes much: