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Blood of world’s oldest woman hints at limits of life

Death is the one certainty in life – a pioneering analysis of blood from one of the world’s oldest and healthiest women has given clues to why it happens.

Born in 1890, Hendrikje van Andel-Schipper was at one point the oldest woman in the world. She was also remarkable for her health, with crystal-clear cognition until she was close to death, and a blood circulatory system free of disease. When she died in 2005, she bequeathed her body to science, with the full support of her living relatives that any outcomes of scientific analysis – as well as her name – be made public.

Researchers have now examined her blood and other tissues to see how they were affected by age.

What they found suggests, as we could perhaps expect, that our lifespan might ultimately be limited by the capacity for stem cells to keep replenishing tissues day in day out. Once the stem cells reach a state of exhaustion that imposes a limit on their own lifespan, they themselves gradually die out and steadily diminish the body’s capacity to keep regenerating vital tissues and cells, such as blood.

In van Andel-Schipper’s case, it seemed that in the twilight of her life, about two-thirds of the white blood cells remaining in her body at death originated from just two stem cells, implying that most or all of the blood stem cells she started life with had already burned out and died.

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Image: [x]  Video: slate.com

As children we’re taught the process of a caterpillar turning into a butterfly, and the story normally goes along the lines of a hungry caterpillar eats and eats until it can eat no longer, then it hangs upside down and forms a chrysalis, from which a beautiful butterfly emerges.

But what actually happens inside the cocoon?

It’s actually quite surprising, the caterpillar does not merely change its body a bit and grow wings, no… It dissolves. Almost entirely. The caterpillar excretes an enzyme which decomposes all the tissues and fibres into basic organic material, leaving only a few ‘cell disks.’

These cell disks comprise all the different types of cells in an adult butterfly - its eyes, legs, wings, etc. The caterpillar is actually born with them but they just remain dormant until metamorphosis. 

Once all the caterpillars cells have been decomposed the adult cell disks then start to grow, using the organic materials left over, eventually forming the butterfly that emerges a few days later.

"Your circulatory system, from the aorta to arteries to arterioles to capillaries and back up the venous side form a similar continuum. They start off massive and branch and branch again, becoming smaller with each branching until they become so narrow in your capillaries that the red blood cells slowly flow through them single file just in order to fit. The mechanism of how your blood vessels branch is fractal in nature. Physiologically speaking your cells depend on oxygen, without it they die and if enough of them die, you die. In order to effectively oxygenate your tissues your circulatory system has to perform an impressive feat of dimensional architecture. Like the Koch Curve, packing infinite surface area into a finite space, your circulatory system utilizes fractal geometry through branching so that no cell in your body is never more than 3 or 4 cells away from a blood cell. And the amazing thing about this feat is that your blood vessels and blood take up very little space: no more than around 5% of your body!"

For more fractal physiology and chaos theory in medicine check out these past posts.

Feeling Squishy

How squishy are your cells? UCLA’s Amy Rowat studies the texture or squishiness of cells. A cell’s texture can actually tell us important information about our health, and even begin to answer long-held questions about diseases like cancer.

The GIF above is a diagram of a microfluidic device (based on a drawing by Amy), which she uses to measure the cell’s softness or malleability.

From the video:The Squishiness of Cancer Cells

anonymous said:

Tips on studying physiology?

Well, I think i can give you some advice on that, physiology was my best subject!! !!

HOW TO STUDY PHYSIOLOGY: 

1. Print you class slides if you have them: 

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Our physiology teacher provided us with the slides he used to explain the lessons before he gave them, so it’s better if you print them, have a look at them, and try to find the definition of terms you think are important. Then you can ask more questions in that class than you would if you attended it without any work already done. That way you’ll feel more secure, at least that worked for me!!!

2. Work. Your. Notes: 

This is maybe the best advice I can give you. After your classes, take time that afternoon to go through your notes and complete them, point out things you don’t understand, questions you want to ask… I used to leave a space between notes to draw the graphics myself

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As you can see, I draw the flow charts and the graphics and then I attach to it some post.it or piece of paper that I just staple or glue in the corner so I can move it to see the notes below. Here are some more examples: 

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As you can see, I worked really hard with this notes. They may seem a bit hectic, but I understood everything perfectly and I did pretty well in my physiology exam. I also dated my notes and marked them with a page number, so everything was always in order. Your notes don’t need to look pretty or extremely organized as long as you understand what you’re writing and you are working with them so it pays off in the final result!! If you work your notes, you’ll have to reason, to make connections, to really understand everything, and there’s just something about pen and paper than gets things in your brain more easily. At least, that works better for me!! 

3. If you have doubts, consult the almighty Guyton: 

I find it better to try and solve your doubts before asking a teacher, because that way you have to think really hard and maybe you’ll come to a conclusion. If you think things yourself, you’ll notice that you remember everything much much better!!

You can buy a copy of the Guyton book of physiology here and here (follow the second link, it’s cheaper in book depository!!!) There’s also this cute companion which seems useful, and the review book!! Another revue book here! (this last one is an ebook, so it’s pretty cheap). 

4. Use some good apps:

I didn’t use any apps when I studied physiology, but here are some good ones:

If you are an android user: https://play.google.com/store/apps/details?id=com.elsevier.physiologyapp

If you are an apple user: http://appcrawlr.com/ios-apps/best-apps-physiology-class (you have a lot here, just try some of them and decide which one works better for you!!)  

5. Revise as much as you can: 

Revising your notes, for example, every weekend, will help you to remember and understand everything better, because the more we visit a brain connection, the stronger it gets! 

6. Study with questions: 

Once you’ve studied, answering some questions will help you notice if you understood everything. Here are some good pages: 

http://www.fundamentalsofanatomy.com

http://www.gwc.maricopa.edu/home_pages/crimando/BIO201/jcastu5.htm

http://academic.pgcc.edu/~aimholtz/AandP/PracticeQuestions/ANPquestions.html

http://www.ivy-rose.co.uk/Revise/AnatomyPhysiology/index.php

7. Color!!!!: 

I haven’t used this yet, but I can’t wait to buy it and have fun! Who said studying couldn’t be fun?? 

Well, this is everything I have to say for now, I hope this helped you!! If you have any more questions, you can always come back to me! :D 

Crayfish Turn Blood Cells into Brain Cells

by Christie Lepisto

… Scientists (have been) studying crayfish, which continuously regenerate neurons in their sensitive smelling organs and exposed eyestalks. Studying the process, known as neurogenesis, in crayfish could help us understand how humans maintain their brain health, and where the process goes wrong.

Scientists found that crayfish have a natural circuit for harboring blood cells similar to our white blood cells in a ‘nursery’ where they are turned into neurons. The cells are converted to have properties of stem cells, which allows them to be reprogrammed to become neurons.

What surprised scientists in this discovery is the link between the immune system and the regeneration of neurons. The blood cells converted to neurons in crayfish, called hemocytes, are produced by the immune system, in a process that parallels the production of white blood cells that are the front-line troops of the human immune system. In the words of co-auther Dr. Irene Söderhäll, of Uppsala University in Sweden..

(read more: TreeHugger)

photograph by Coniferconifer/Flickr

Everything Science Knows About Hangovers

The light coming in through the window is so … there. You’d kill for a glass of water but die if it came with food. Your guts are in full rebellion; whatever happens next is going to happen in the bathroom. You have at least a couple of the following symptoms: headache, malaise, diarrhea, loss of appetite, fatigue, nausea, the shakes. You might also be dehydrated and feel generally slow—a little stupider, a little less coordinated.

You, my friend, have a hangover. And you can take heart in the fact that you’re not alone. Some 77 percent of all drinkers report suffering from them. (The scientific term for the other 23 percent is “jerks.”) But here’s the amazing part: The underlying cause of your suffering remains a mystery. “What causes a hangover? Nobody really knows,” says epidemiologist Jonathan Howland. “And what can you do about it? Nobody knows.”

Alcohol has long been the only recreational drug for which scientists could not articulate a mechanism of action—which is to say, no one knew how it got you drunk, and no one knew how it got you hungover. 

Read more (via wired.com)

That said, I can only leave you with this marvellous nerdy drinking song. 

Cheers!!

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Study Says Dinosaurs In Between Warm and Cold Blooded

by Jonathan Webb

Dinosaurs fit in an intermediate class between warm and cold blooded animals, a study in the journal Science claims.

Scientists compared the growth rates of hundreds of living and extinct species, using growth rings and bone size to calculate the rates for dinosaurs. They linked growth rate to metabolic rate, the measure of energy use that divides warm and cold blooded animals.

The study suggests that the dinosaurs fall into a middle category, in a fresh contribution to an enduring debate.

Warm blooded animals, like mammals and birds, need a lot of fuel and use that energy to their advantage, including faster movement and boosted brain power. In burning all that food they also maintain a high, stable body temperature…

(read more: BBC Nature)

Scientists Solve 40-year Mystery of How Sodium Controls Opioid Brain Signaling

Scientists have discovered how the element sodium influences the signaling of a major class of brain cell receptors, known as opioid receptors. The discovery, from The Scripps Research Institute (TSRI) and the University of North Carolina (UNC), suggests new therapeutic approaches to a host of brain-related medical conditions.

“It opens the door to understanding opioid related drugs for treating pain and mood disorders, among others,” said lead author Dr. Gustavo Fenalti, a postdoctoral fellow in the laboratory of Professor Raymond C. Stevens of TSRI’s Department of Integrative Structural and Computational Biology.

“This discovery has helped us decipher a 40-year-old mystery about sodium’s control of opioid receptors,” said Stevens, who was senior author of the paper with UNC pharmacologist Professor Bryan Roth. “It is amazing how sodium sits right in the middle of the receptor as a co-factor or allosteric modulator.”

The findings appear in an advanced online publication in the journal Natureon January 12, 2014.

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Scalp is the soft tissue layer covering the bony vault over the brain. It is usually described as having five layers:

S: The skin on the head from which head hair grows. It contains numerous sabaeceous glands and hair follicles

C: Connective tissue. A thin layer of fat and fibrous tissue lies beneath the skin.

A: The aponeurosis called epicranial aponeurosis (or galea aponeurotica) is the next layer. It is a tough layer of dense fibrous tissue which runs from the frontalis muscle anteriorly to the occipitalis posteriorly.

L: The loose areolar connective tissue layer provides an easy plane of separation between the upper three layers and the pericranium.

P: The pericranium is the periosteum of the skull bones and provides nutrition to the bone and the capacity for repair.

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