A fascinating book for students and adults is “ExtraOrdinary” by Dorling Kindersley (DK), 2014, ISBN 978-1-4659-2766-6.
I am drawing material from the Human Body section, one of 10 sections that range from Space to History. Beautifully illustrated, “ExtraOrdinary” is a book that you can open up to any of the sections and find some amazing facts. The strength of DK books is that they use a number of expert contributors and high caliber graphic illustrators.
First, let’s consider your outsides such as hair, skin and the organisms that live there. A typical adult has 21 square feet of skin, weighing 7 pounds. It is the largest organ in the human body. Your skin is thickest on the soles of your feet (1/4 of an inch) and thinnest on your eyelids (1/200 of an inch) Everyone has eyelash mites that live in your eyelash follicles.
Your hair is dead tissue growing out of hair follicles. An average adult has 100,000 hairs (mostly on their head), losing and replacing 80 hairs a day. Your hair typically grows half of an inch per month. Bacteria are the most numerous organisms on your skin, numbering in the billions (nine zeroes). Bacteria in your armpits nourished by sweat, creates smelly chemicals that cause B.O. (body odor).
Your bones will last long after your death. Bones are made up of two ingredients: calcium salts and collagen. In the grave, collagen rots away. The inner part of your bones have fat storing yellow marrow and red bone marrow, which make blood cells. You are born with 300 bones; as you grow to an adult, some bones fuse, leaving you with 208 bones. Your neck has seven bones, as many bones as a giraffe, whose neck bones are much larger.
Your blood is red because of the hemoglobin that carries oxygen to the farthest cells of your body. Human blood has three components: plasma, 55 percent, red blood cells 44 percent and white blood cells and platelets 1 percent.
The average adult has 93,000 miles of blood vessels, enough to wrap more than three times around the Earth’s equator The average adult has 11.5 pints of blood. This fluid contains 25 trillion (a trillion has 12 zeroes) red blood cells. Each red blood cell contains 250 million hemoglobin molecules, each of which can carry 1 billion oxygen molecules. An average red blood cell lasts 120 days. During a 70 year lifetime, a heart beats 2.5 billion times.
As for digestion, 30 tons is the average weight of food consumed in a lifetime. 24 pints of food, fluid and digestive fluids flow through your digestive system each day; 32 hours is the average transit time from eating food to passing it out of your colon.
Your coiled small intestine is coated with tiny villi extensions that greatly increase the absorbing area. As for breathing, we take an average of 25,000 breaths per day. Two thousand gallons of air pass into your lungs each day; 1,900 gallons are exhaled.
You have 10,000 taste buds on your tongue. You can also detect 10,000 different smells. Your eyes can detect 10,000 different colors. Your retina has 120 million rods (black/white) sensors in each eye. There are only 7 million cones (color) sensors in each eye. The cones need more light to be actuated so at night, most stars appear white.
Your brain has 2 percent of your body weight but uses 20 percent of your oxygen consumption. Our brains contain about 100 billion neurons (nerve cells). There are 100 trillion connections between neurons, accounting for the incredible storage of the human brain.
The speed of impulses between neurons is over 200 miles an hour. Typically, 2,500 neurons fire at a time. Our brains are 80 percent water. The time for a nerve signal to pass from your brain to your big toe is 1/100 of a second. Headaches usually don’t involve the brain. They are commonly caused by muscle tension in the neck and under the scalp.
SKY SIGHTS AHEAD: Tomorrow morning, the brilliant planet Venus and the bright planet Jupiter will be closest low in the 6:15 a.m. dawn. At dawn on Tuesday, the crescent moon will appear above the planet Mars On Friday morning, a slender crescent moon will appear above Venus and Jupiter.
Nov. 17 will be the peak for the Leonid meteor shower. Best time is evening hours.
The Frostburg State Planetarium will have free public programs on Nov. 15 at 6 p.m. and 7 p.m. The featured presentation is “Where are the Aliens?” The Planetarium is in room 186 of the Gira Center. The Gira Center entrance closest to the planetarium is near the FSU Clock Tower.
Bob Doyle invites any readers comments and questions. E-mail him at email@example.com. He is available as a speaker on his column topics.