This tumblr's for all the great men and women of science for whom we owe our current understanding of the natural world; their achievements, their failures, and even their quirks, we celebrate them all.
For Science. For Inquiry. For Humanity.
“Nouveau recueil d’ostéologie et de myologie” | Toulouse, 1779. Etching. National Library of Medicine
Jacques Gamelin, artist
“Man’s mind, once stretched with a new idea, never regains its original dimensions”
Oliver Wendell Holmes Sr.
In order to understand why vaccines work, first you must know a few things about our bodies immune system.
Our body/immune system has two types of defenses to fight off pathogens:
- The innnate or non specific immune response, and
- The adaptive or specific/acquired immune response
The Innate Immune Response
-The innate immune response has two components: the noncellular and cellular components. The noncellular component is our first line of defense against pathogens, and examples include our skin (acting as a barrier against pathogens), and the strong acidity of our stomach (which is able to kill pathogens). The cellular component includes phagocytosis, in which certain cells (such as macrophages) are able to literally engulf and destroy the pathogen. The phagocytotic cells notice their invaders due to the features on their membranes, including carbohydrates, lipids and/or proteins.
-The components that make up the innate immune system are always present in our bodies. They are always ready to go after a pathogen if it detects the general features which I mentioned above, that make it detectable as such. The innate immune response has no ‘memory’. If it attacks a pathogen on Monday, and it sees it again on Thursday, it will treat it equally the same; the second time around won’t be easier or quicker to deal with the pathogen.
That being said, next….
The adaptive/specific immune response
-Whereas the innate immune response is nonspecific, the opposite is true of the adaptive immune response. This defense kicks in once a particular antigen has been detected. What is an antigen? To put it in as few terms as possible: it’s a substance on the pathogen that will cause your body to create antibodies as a response, as well as antigen-specific defending cells, or lymphocytes, to be produced.
-The downside of the adaptive immune response is that it takes a while to kick in and it won’t do a great job in the beginning. However, the adaptive immune response does have a sort of “memory”. If a certain pathogen gets into your body which triggers your adaptive immune response for the very first time, your body won’t be great at killing it. HOWEVER, the second time your body is exposed to this pathogen, your adaptive immune response will be very efficient at producing these antibodies which will destroy the pathogen. T-lymphocytes are produced which directly contact and kill the invading pathogen, and B-lymphocytes produce antibodies which are then sent to kill the pathogen. These cells are often called T-cells and B-cells and they are what people who have AIDS have very low counts of. This is why their immune systems are extremely compromised.
-Okay, so you might be thinking: the second time this pathogen enters, the body will attack it, and you’ll be fine. So what’s the big deal? What if the pathogen that enters is deadly the first time around in it’s normal state? Your body will never have gotten the chance for a second try, because you’ll have died. So what to do, what to do….
The ideal situation would be that we would be exposed to the pathogen the first time around, survive (maybe go through a bit of hell, but survive) and then the second time we’re exposed to it, be OK. So how is this possible…? Vaccines deliver a shot of pathogens with reduced virulence (less harmful). Our body, having been exposed to them for the first time, slowly attacks this pathogen-but we don’t die, because it’s not as strong as the usual dose would be. Perhaps the pathogens have been heat killed-when they enter our bodies, they are dead but they still have antigens on their outer membrane, so our bodies can still create antibodies! Then, the second time we are ever exposed to this pathogen, our body will be able to quickly, efficiently create the proper antibodies to attack the pathogen. Much of this is thanks to Louis Pasteur and Edward Jenner (creator of the smallpox vaccination!)
-Written by me, polylinker. The information came from what I learned in class the last few days. I was inspired to share this knowledge with the rest of you who care. If you have any comments, suggestions, further reading, or any corrections for this please feel free to send me a message. :)
Anatomy Lesson: Trapezius Muscle
In human anatomy, the trapezius is a large superficial muscle that extends longitudinally from the occipital bone to the lower thoracic vertebrae and laterally to the spine of the scapula (shoulder blade). Its functions are to move the scapulae and support the arm.
Technique that involves turning the brain into ‘soup’ and counting the nuclei of nerve cells reveals that we’re 14bn short
“We found that on average the human brain has 86bn neurons. And not one [of the brains] that we looked at so far has the 100bn. Even though it may sound like a small difference the 14bn neurons amount to pretty much the number of neurons that a baboon brain has or almost half the number of neurons in the gorilla brain. So that’s a pretty large difference actually.”
Ten Things Bacteria Can Do That You Can’t
We humans like to think we’re pretty great. We have things like the Mona Lisa, and the Large Hadron Collider, and The Kind of Chocolate Sauce That Turns Solid When You Put It On Ice Cream. Still, it turns out that if aliens were to visit planet Earth and kidnap the dominant species, they’d go for bacteria over us any day. There are more of them, they’re more diverse, they’ve been around a lot longer, and between the lot of them, they’ve achieved a lot more. Have a look at ten things that bacteria do with their bare flagella that we could never manage to duplicate.
10. Live for 34,000 years.
In Death Valley, researchers found salt crystals that had tiny, fluid-filled pockets in them. In those pockets were 34,000-year-old bacteria. Not a species of bacteria that was 34,000 years old; an actual 34,000-year-old organism that had put itself in suspended animation for tens of thousands of years. And they didn’t look a day over thirty.
9. Be their own ecosystem.
In a goldmine in South Africa, there isn’t much room for life. There’s no sun, and no complex plants or animals providing nutrients to feed on. There is, however, a kind of bacteria. One kind of bacteria. It takes the heat of the mine and the water that fills the bottom and harvests everything it needs from the elements - literally. There is no life in the mine besides Desulforudis audaxviator, the world’s most self-sufficient organism.
8. Make gold nanoparticles.
Gold sprinkles the land, but in only a few places does it come in solid enough form that it’s worth collecting. And the main reason it does that is bacteria. Certain bacteria dissolve gold into nanoparticles, and those nanoparticles move freely through the soil until they collect in certain areas. Whenever a prospector strikes it rich, he or she should thank the humble bacteria. I’m guessing they don’t, though.
7. Glow in the dark.
Bacteria are the source of most bioluminescence in sea life. Some squid carry bacteria in their bodies that allow them to glow, and many bioluminescent fish have pouches of bacteria which manufacture the enzyme luciferase, which glows in the dark. And not just under black light. That’s cheating.
6. Be the world’s tiniest ninja.
Nanobacteria occupy only 20 nanometers. They’re somewhat controversial, since some scientists believe that such a small space can’t possibly hold the components necessary for life. And maybe that’s true. For these bacteria are not life - they are death! In the lab they tend to occupy dying mammalian cells. In real life, they’ve been linked to numerous health problems - but the link has never been certain. They are silent. They are untraceable. And they are deadly.
5. Live on Mars.
Oh, I’m not saying they do. I’m saying they could. Discoveries of colonies of live bacteria in liquid pockets in the dry valleys of Antarctica, they could definitely live somewhere below the surface of Mars.
4. Survive in boiling water.
Most of us are only comfortable in that tiny fraction of an inch that our shower knob that allows us to get the right temperature of water. If we so much as nudge the knob, or if someone in the room flushes the toilet, we jump out of the water, screaming. Not so with botulism bacteria. This deadly little number can survive boiling water. It’s only when the water is pressurized, so it boils at a higher temperature, that botulism dies off.
3. Modify their own genes.
Bacteria gain new abilities by swiping genes from other bacteria they encounter. If humans were able to do the same, it would be a little like being able to grow spots after petting a leopard. The process is called horizontal gene transfer, and it allows the bacteria to gain resistance to antibiotics.
2. Protect themselves from radioactivity and toxic environments
Some kinds of bacteria that live in radioactive areas have worked out ways of defending against taking in heavy metals. Not only is this of interest to biologists, but engineers are working out ways of using these bacteria to harvest heavy metals. Humans shrink from Uranium. Bacteria pick it up and use it as armor.
1. Digest your food.
Yes, you can’t even do that on your own. As thousands of yogurt commercials have no doubt told you, you need bacteria to help you. And while they’re down there, they do things like protect against other types of infection, regulate your immune system, and some, Lactobacillus and Bifidobacterium, even fight elements that cause cancer.
That’s right. The goop in your stomach fought cancer today. And what did you do? Via The Huffington Post, Wired, Discovery, The Charlotte Observer, Wired, Science AGoGo, Making Your Own Beer, Current.com, Nanowerk, and The Naked Scientist.
Humanity has a new matriarch: a hominid named Ardi who lived in Ethiopia 4.4 million years ago. Anthropologists have unveiled the results of 17 years of research on a new species named Ardipithecus ramidus, presenting a rich trove of fossils including the partial skeleton of the small-brained, 110-pound female. Ardi is 1.2 million years older than the famed “Lucy,” of the species Australopithecus afarensis, and experts say the find fundamentally changes our understanding of human evolution.
Study coauthor Tim White says that Ardi provides clues to what the last common ancestor shared by humans and chimps might have looked like before their lineages diverged about 7 million years ago…. But despite being “so close to the split,” says White, the surprising thing is that she bears little resemblance to chimpanzees, our closest living primate relatives [Time].
Ardi’s pelvis, leg, and feet bones indicated that she walked upright on two feet, but her opposable big toes suggest that she was also comfortable climbing trees. Her hand, arm, and shoulder bones indicate that she didn’t often swing through the trees, though; instead she probably walked on her palms along tree branches like some extinct apes.Based on Ardi’s anatomy, it appears that chimpanzees may actually have evolved more than humans — in the scientific sense of having changed more over the past 7 million years or so [Time]
image credit: Wired.com
mullerium epithelium from a human fallopian tube.
Three dimensional cell culture of breast cancer cells (MCF-7 cell line) (1000X)
It depends on how you view it.
Your body is composed of different types of tissues: Fat, bones,teeth, brain, the nervous system, connective tissue, blood, lymph, the digestive tract, urine, and the air in your lungs.
But by mass, 65–90% of our body’s cells are water (H2O). So, oxygen takes up a large portion of our body mass. Almost 99% of the mass of the human body is made up of the six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. About 0.75% of the remainder is composed of only five elements: sodium, phosphorus, potassium, sulfur, and chlorine.
The average 70 kg adult has about 6.7 x 1027 atoms. Doesn’t seem like so much with scientific notation, but really, that is a lot! To give you a better idea, let’s show the real number without scientific notation. That is 67000000000000000000000000000 atoms!
The body is composed of 60 elements from the Periodic Table; but the amount of each element vary by individual.
Let’s view it another way:
There is water in your cells, and proteins such as that in your hair, skin, and nails; there is the fat in your body/cells, and the apatite in your bones; there are carbohydrates, such as glycogen and glucose DNA; Dissolved inorganic ions such as sodium, potassium, chloride, bicarbonate, phosphate; Gases such as oxygen being carried through your blood, carbon dioxide, nitrogen oxide, hydrogen, and carbon monoxide. These may be dissolved or present in the gases in the lungs or intestines. There are also many other small molecules in your cells, such as amino acids, fatty acids, nucleobases, nucleosides, nucleotides, vitamins, cofactors.
However your view it, your body is a very complex, giant system composed of many small details.