Source: www.spyderwood.com

The short answer: no. Is it possible that of the seven billion people in the world, all sleeping at some point during a 24 hour period, some might accidentally eat a spider during their sleep? Sure, it’s possible but very unlikely.

The source of this urban legend is generally unknown but a plausible explanation (from snopes.com) is this. In the early days of the Internet, a columnist named Lisa Holst wanted to prove a point that many people would believe all sorts of crazy things if they saw it in a list of “facts,” that had been emailed to them. She completely made up a list of false facts to prove how easily they would be accepted by a certain number of gullible recipients in the (then relatively new) world of email. One of her facts was that the average person swallows X number of spiders in their sleep every year.

I believe this fact (that a columnist made this up) to be much more likely than the fact that anyone ever swallows a spider in their sleep. However, doing a quick search for a writer named Lisa Holst, or the computer magazine she wrote for in 1993 “PC Professional” turned up empty. Well, not completely empty. There were a lot of results, but they were all related to the fact that Lisa Holst supposedly fabricated this list. There was nothing that linked to any of her other writing, or even to a real magazine called PC Professional.

So the general consensus is that the fact that people eat spiders in their sleep is a myth. But the origin of the myth is quite possibly a myth as well. Go figure.

And for just a little extra fun… when I first read this question, I immediately thought of the guy in the lunatic asylum from Bram Stoker’s, Dracula. He was eating flies but decided it would be better to just eat the spiders who ate the flies. Kind of a two-for-one deal. Anyway, here’s a clip from the 1931 version of the movie. Eating Spiders, Dracula, 1931

Cross Sections of a hair and follicle. Source: www.ohiohealth.com

To understand this, we should first answer what causes hair color to begin with. All hair, whether on your head, your arms, or your cat’s tail has pigment cells called melanocytes. These melanocytes produce a pigment called melanin- more specifically, the chemicals eumelanin and pheomelanin. Hair with more eumelanin will be darker (brownish to black) and hair with more pheomelanin will have a red/orange/yellow tint. Hair with less of either will be lighter.

These melanocytes also pass this pigment to cells called keratinocytes (which produce hair’s main component, the protein keratin). When the keratinocyte cells die, they keep the melanin which is what is visible and gives hair its color.

As we get older, the melanocytes get less active, thus producing less pigment and making your hair lighter. Eventually all the melanocyte cells die and there are none left to produce any color.

So what are the factors that control this production of pigment? Many are genetic. Alleles of the recently-discovered MC1R gene have been shown to produce red hair in mammals. Other genes, many as yet unidentified, are likely responsible for other hair colors. According to Laurence Meyer, a dermatologist at the University of Utah, “Generally speaking, among Caucasians 50 percent are 50 percent gray by age 50. There is, however, wide variation.” Of course, these percentages are different for different ethnic groups, which further emphasize the role genetics play in the color of your hair.

References:
About.com: http://chemistry.about.com/od/howthingsworkfaqs/f/why-does-hair-turn-gray.htm
Scientific American: http://www.scientificamerican.com/article.cfm?id=why-does-hair-turn-gray
Image: http://www.ohiohealth.com/mayo/images/image_popup/sn7_skinlayers.jpg

One of the first microscopes. Image source: http://www.dipity.com

In the late sixteenth century, two Dutch eyeglass makers discovered that objects appear magnified when viewed through multiple convex lenses in a tube. For this simple discovery, Hans Janssen and his son Zaccharias are considered by some to have invented the microscope around 1590. About this same time, another eyeglass maker from Holland, Hans Lippershey came up with the same idea and is also considered by some to be one of the inventors.

“The coining of the name “microscope” has been credited to Giovanni Faber, who gave that name to Galileo Galilei’s compound microscope in 1625. [wikipedia]

Anton van Leeuwenhoek (1632-1723) is really considered to be the “father of microscopy” when he worked as an apprentice in a dry goods store where magnifying glasses were used to count the threads in cloth. He taught himself new methods for grinding and polishing lenses of great curvature which gave magnifications up to 270 times, the greatest known in that day. These led to the building of his microscopes and the biological discoveries for which he is famous. He was the first to see and describe bacteria, yeast plants, the teeming life in a drop of water, and the circulation of blood corpuscles in capillaries. During a long life he used his lenses to make pioneer studies on an extraordinary variety of things, both living and non living, and reported his findings in over a hundred letters to the Royal Society of England and the French Academy. [source about.com]

You might think the animal with the longest gestation period would be one of the larger mammals, but in fact it is the Alpine black salamander. It is a viviparous amphibian which lives in the high altitude Swiss Alps. At altitudes above 4,600 feet, it’s gestation period can be up to 38 months. It bears two fully metamorphosed young.

Image source: http://supercentenarianstudy.blogspot.com/

According to Wikipedia, there are less than 100 verified centenarians (persons living past the age of 100). And of centenarians, about 1 in 1,000 will live to be a super-centenarian (one who is living into their 12th decade.) Even rarer, is one who lives past the age of 115, which current estimates predict only 1 in 50,000 centenarians will reach.

An interesting study is observing the trend life expectancies have been changing over the past century. The following graph is the average life expectancy in the United States for each decade since 1900.

Note, statistics weren’t as accurately kept for the first part of the century but the overall trend is probably fairly accurate. Source of these data: U.S. Dept. of Commerce, Bureau of the Census. The report can be downloaded here.

The processes that occur in the body at the cellular level almost all have an underlying element of chemistry. How is food converted to energy? How does oxygen move from the lungs to the blood to the parts of the body that need it? Both questions that can’t be answered without chemistry. What is the pH of our blood and other bodily fluids? Why does the pH matter? How is sugar converted into glucose, or what is their relationship anyway? More questions that require a knowledge of chemistry.

Click to see more chemistry and nursing links

A good nurse will not only know what is happening in a patient’s body, but they’ll have a good idea why. While some nursing programs are more heavily-laden with chemistry classes than others, the better programs are likely the ones that place more than a cursory emphasis on some of the sciences other than simply biology.

]]> http://TheScienceExperts.com/answers/why-is-chemistry-important-to-nursing/feed/ 0 http://TheScienceExperts.com/answers/who-discovered-the-mitochondria/ http://TheScienceExperts.com/answers/who-discovered-the-mitochondria/#comments Mon, 20 Sep 2010 02:13:25 +0000 Admin http://TheScienceExperts.com/answers/who-discovered-the-mitochondria

The mitochondrian was first identified at the end of the 19th century by a German pathologist and histologist (tissue researcher) named Richard Altmann. It was given the name “mitochondria” by Karl Benda, a German physician. (1857-1933). [source: wikipedia] Altmann is known for his work involving cell theory and structure. In his study of animal cells, he investigated small granules in the protoplasm of the cell. He called these particles- bioblasts, which he postulated were elementary organisms that had metabolic and genetic autonomy. Today Altmann’s bioblasts are known as mitochondria.

So what are mitochondria?

Mitochondria are the powerhouses of the modern cell, providing some 90% of the energy needed for survival. In 1963, scientists discovered mitochondria had their own DNA, arranged in circles, containing the blueprints for 37 of the molecules mitochondria need to create to generate energy.

The single-cell embryo that results from the merger of the egg and sperm has a solitary nucleus with a matching set of chromosomes with about 100,000 genes from the sperm and 100,000 from the egg. These are coded in about three billion base pairs along the strands of DNA.

The fertilized egg, and all of its descendant cells, divide their chromosomes into two mirror images and then split into new cells with each cell obtaining a full set of genes.

By comparison, the DNA of mitochondria has only 16,569 base pairs and these are all inherited from the cytoplasm of the egg. The male makes no contribution to this complement.

Making Fuel for the whole body

Each mitochondrion has a convoluted inner membrane, like a giant nucleus, within its smooth outer membrane. It generates energy by relaying electrons along a series of proteins embedded in the inner membrane. This series is called the respiratory chain. The electrons interact with oxygen and protons to form water and energy.

Mitochondria direct the energy released from the oxidation of hydrogen to pump protons across the inner membrane. This creates a charge and chemical differential that facilitates the synthesis of ATP Synthase which in turn facilitates the creation of ATP (adenosine triphosphate). ATP is liberated into the cell cytoplasm and distributed throughout the body as fuel for all cellular activities.

The process depends upon a steady supply of oxygen and hydrogen (H+) as well as electrons supplied from food. Should any of these be in short supply, the cells rapidly run out of fuel and die. Should mutations inhibit the process of ATP production, the cells begin to weaken.

Source: Wikipedia and This Magic Sea.

The reaction is thus: 6H2O + 6CO2 –> C6H12O6 + 6O2

In non-chemical terms this says: six molecules of water plus six molecules of carbon dioxide react to produce one molecule of glucose and six molecules of oxygen.

There is a nice description of this reaction and more information about photosynthesis at Maricopa Community College here. They add, “The conversion of unusable sunlight energy into usable chemical energy, is associated with the actions of the green pigment chlorophyll. Most of the time, the photosynthetic process uses water and releases the oxygen that we absolutely must have to stay alive.”

A more scientific method is through close observation and comparing your tadpole to a known chart. The below images and chart should help you get started.

First, where are the eyes? Are they lateral or dorsal?

Next, check the vent location. You may have to hold the tadpole in your hand to check this. Is it Medial or Dextral?

Next you’ll need to check the tail musculature. Is it high, medium or low?

And lastly, you’ll compare these results with the tadpole anatomy wheel below. (Click on the picture to see a full-size image.)

Following this procedure should give you a good idea and help you narrow it down. Of course, the only surefire way to identify the species will be to wait and see what kind of frog it grows into. The source of these images is the Tutorial on Tadpole Morphology from the U.S. Geological Survey (USGS).