#human biology

[vs-space-orcs]

Alien crewmate: Welcome back, Human James. You were gone suddenly for two weeks! What kept you on-planet for that long?

Human James: Oh I had my appendix taken out.

Alien crewmate: What is an 'appendix?'

Human James: It's an internal organ humans have that sometimes gets infected and needs to be removed.

Alien crewmate: You can just REMOVE an entire ORGAN from your body?! And be fine two weeks later?!

Human James: yeah we don't actually need our appendix and no one really knows what it's for. Most people think it's a useless organ leftover from our evolutionary ancestors that were herbivores. Though there's research to suggest it might have some use. About 20% of humans get appendicitis and need it removed sometime in their lifetime.

Alien crewmate: two weeks?? Two weeks?! To recover from having an entire internal organ removed?! Humans are so scary.

Human James: well it's a pretty small internal organ and I'm not 100% recovered until another month.

Alien crewmate: I am never fucking around with you ever again Mr Apex Predator that can fully recover from having an internal organ removed in less than two months. Human biology is insane.

Human James, shrugging: If you say so.

[reasonsforhope]

"For the first time, genetically modified pig kidneys provided “life-sustaining kidney function” during the course of a planned seven-day clinical study—a first step in addressing the critical crisis worldwide of kidney donor organ shortage.

The University of Alabama’s pre-clinical human study at Birmingham also advances the science and promise of xenotransplantation as a therapy to potentially cure end-stage kidney disease—just as a human-to-human transplants can.

“It has been truly extraordinary to see the first-ever preclinical demonstration that appropriately modified pig kidneys can provide normal, life-sustaining kidney function in a human safely and be achieved using a standard immunosuppression regimen,” said UAB transplant surgeon scientist Jayme Locke, M.D., director of UAB’s Comprehensive Transplant Institute and lead author of the paper...

The peer-reviewed findings published last month in JAMA Surgery describes the pioneering pre-clinical human research performed on a recipient experiencing brain death...

The pre-clinical human brain death model developed at UAB can evaluate the safety and feasibility of pig-to-human kidney xenografts, or transplants, without risk to a living human. It is named for transplant pioneer Jim Parsons, an organ donor whose family generously donated his body to advance xenotransplant kidney research, like the latest patient did.

A Critical Need

Kidney disease kills more people each year than breast or prostate cancer, while more than 90,000 people are on the transplant waiting list. More than 800,000 Americans are living with kidney failure and 240 Americans on dialysis die every day. The wait for a deceased donor kidney can be as long as five to 10 years, and almost 5,000 people per year die waiting for a kidney transplant.

Groundbreaking Study Details

The 52-year-old study subject for this research lived with hypertension and stage 2 chronic kidney disease, which affects more than one in seven U.S. adults, or an estimated 37 million Americans. As part of this study, the subject had both of his native kidneys removed and dialysis stopped, followed by a crossmatch-compatible xenotransplant with two 10 gene-edited pig kidneys, or UKidney.

The transplanted pig kidneys made urine within four minutes of re-perfusion and produced more than 37 liters of urine in the first 24 hours. The pig kidneys continued to function as they would in a living human for the entirety of the seven-day study. Also, the kidneys were still viable at the time the study was concluded.

“In the first 24 hours these kidneys made over 37 liters of urine,” said Dr. Locke. “It was really a remarkable thing to see.” ...

Gene editing in pigs to reduce immune rejection has made organ transplants from pigs to humans possible. The natural lifespan of a pig is 30 years, they are easily bred, and they have organs of similar size to humans. Genetically modified pig kidneys have been extensively tested in non-human primates, and the addition of UAB’s preclinical human research model—the Parsons Model—now provides important information about the safety and efficacy of kidneys in human transplant recipients."

-via Good News Network, September 17, 2023

[inthemaelstrom]

Stop listening to influencers about birth control

Learn some goddam biology about your own body. Stop letting uneducated idiots tell you that birth control "makes you select men who are traditionally less masculine" and bullshit like that. FFS. Your feminist foremothers did not fight for access to birth control for you to go back to the age of ignorance. Use those brains!

Start here: https://www.plannedparenthood.org/planned-parenthood-greater-new-york/campaigns/get-birth-control-that-works-for-you

And read this. There's no paywall.

https://wapo.st/3IM6v5t

[carionto]

This has probably been transcribed before but I don't know what tags to find it under, so imma just do it again cuz this kind of stuff feels very relevant to know, more evidence that Humans are weird as fuck and our brains just make shit up. [Twitter thread by user named foone as a long image I stumbled upon on Pinterest]: _______________________________

You want to know something about how bullshit our brains are? OK, so there's a physical problem with out eyes: We move them in short fast bursts called "saccades", right? very quick, synchronized movements. The only problem is: they go all blurry and useless during this

Having your vision turn into a blurry mess every time you move your eyes is obviously not a good idea, so our brains hide it from us. Now imagine you're an engineer and you have this problem

You've got some obvious solutions you could do.

make the vision go black during movement. (Some VR games do this!)

just keep showing the last thing we saw prior to movement

Both are good options with different downsides, but OH NO. this is assuming everything makes sense and is chronological and (regular) logical.

Your brain does neither of these options, really.

First, it basically puts your visual system on "pause".

You're not seeing blackness or even nothing, you're just not seeing period.

then when you finish your saccade, it shows you what you now see at the new position. and then it pretends it can time travel.

It seriously shows you the image at the new point, but time-shifts it backwards so that it seems like you were seeing it the whole time your eyes were moving.

And because your brain is not a computer with a consistent clock, this shit works.

You can see this effect happen if you watch an analog clock with a second hand.

Look away (with just your eyes, not your head), then look back to the second hand.

It'll seem like it takes longer than a second to move, then resumes moving as normal.

That's because your freaking visual system just lied to you about HOW LONG TIME IS in order to cover up the physical limitations of those chemical camera orbs you have on the front of your face.

We've known about this effect for over 100 years, it's called "Saccadic masking" and more specifically Chronostasis. Your visual system lies to you about WHEN things happen by up to half a second (!) just to avoid saccades blurring everything.

So while I firmly believe we're basically just overgrown biological computers, we're apparently computers programmed by batshit insane drunkards in Visual Basic 5.

And you might think "hey wait, wouldn't my vision 'pausing' for half a second have all kinds of weird effects on moving objects? why don't they appear to stutter when moving?"

and the answer is simple! your brain has EVEN MORE UGLY HACKS on top of this to avoid you seeing that

If you've got a clock where the second hand doesn't "tick" but instead smoothly rotates, you won't see this. Because your brain recognizes it's moving and adjusts what you see to make sure it sees the "right" thing.

It's only really obvious with periodically moving things like a clock hand, because it's not moving (so not triggering the movement-during-chronostasis hack) but it moves at a set rate, so you can notive that rate appearing to change.

It's tempting to think of your eyes and visual system as a camera just dumping a video feed into your conscious brain but taht's so very, very not the case. What you think you see and what your eyes can actually see are two exceptionally different things.

The big obvious one being the blind spot. Vertebrate eyes are wired backwards so we've got a blind spot in each eye where the enrves enter into the eye. About 6 degrees of your vision in each eye is just not there, as there's no light sensitive cells there.

Do you see a blind spot, right now? No, you probably don't. Close one eye! There's now no way for the other eye to fill in the gaps. Still, no blind spot… Your visual system is lying, and making up content it thinks is there. You literally cannot see what you think you see.

Here's another one: You can see in color, right? (well, some of you can't. Sorry) You can see in color all throughout your vision, it's color everywhere?

Well, most of the cone cells (Which are sensitive to color) are in the fovea, a little spot in the center of your vision.

So outside of that center-of-vision spot, you have very little color perception. There's some but it's very limited compared to your main color vision. But I bet if you shift your attention to your peripheral vision right now, it's in color.

Your vision system is lying. It's remembering what colors things are and guessing and filling in the gaps. It's basically doing a Ted Turner colorization process on your non-central vision.

There's even weird effects like what's called "Action-specific perception". If you get a bunch of white balls of various sizes and toss them at people then ask them to estimate the size of the balls thrown at them, they'll have a certain size estimate, right?

Now repeat the experiment but ask them to try to hit the balls back with a bat, and suddenly all the estimates shift larger. They actually see the ball as bigger because they need to hit it. Their vision is exaggerating it to make it easier to see!

Which just goes to show, like I said, your vision is not a camera. Perfect accuracy is not one of its goals. It does not give any shits about "objective reality", that's not important.

What's important to the evolution of the visual system is any trick that helps you survive, no matter how "dumb" or "weird" it is.

So if you want an accurate visual representation of what things look like? Use a camera. Not your eyes.

In any case the original point was that while you might know this about your eyes being poor cameras that lie to you, you might still think that at least they're consistent, time-wise. They don't screw with your sense of time passing, just to make up for visual defects. NOPE!

If you can't get it don in time, turn back the clock and pretend you did. That's a perfectly good solution when you're the visual system.

BTW @/hierarchon reminded me of a neat trick with saccadic masking: go look in a hand mirror. No matter how close you bring it to your eyes, and how much you look around, you will never see your eyes move. You're blind during those movements. But you still think you are seeing.

She additionally pointed out that your phone's selfie-mode is NOT a mirror, and it has a slight delaye, so you can see your eyes moving in it.

And for fun, here's wikipedia's example of the blindspot. Stare at L with only your left eye, adjust the distance, and the R will disappear. You don't see "nothing" or "black", you see the background, because you expect to.

This is why laser damage your retina can be so insidious. Your visual system already can hide "holes" in your vision, what's one more to hid? So you damage a small spot of your retina and your visual system covers it up.

But since you didn't go "WELL THAT WAS TERRIBLE I BETTER TAKE BETTER CARE OF MY EYES" and stop fucking with lasers, you keep doing it. Eventually you accumulate so much damage that your visual system simply cannot manage hiding it all and your vision rapidly degrades.

The other reason lasers are so dangerous is that they don't necessarily trigger the same responses as regular incoherent light. Your pupil reflex is only triggered by some special cells in the center of your eye, so an off-center laser might not cause your iris to contract.

And infrared laser light is just as dangerous as visible laser light, but can't trigger your blink reflex. Your eyes automatically close when exposed to bright light, but they can't detect infrared light. Despite not seeing it, it still causes damage.

Anyway, back on how amazing and crazy your vision is: There was an experiment back in 1890 where someone wore glasses made with mirrors in them to flip their vision. After about 8 days, they could see just fine with them on. Their vision system had started "flipping" the image.

(I say flipping in quotes because it's not as simple as it started showing the pixels at the top row on the bottom row, cause our vision doesn't work like that) It only took them a few hours to get back to normal after taking these glasses off, though.

The last really fun part about this flipping experiment: your eyes already do it. Based on how our vision is wired, we should be seeing everything upside down.

We don't, but only because our visual system has had a whole life to adapt to this.

BTW, since a few people have brought it up: There's a great sci-fi novel by Peter Watts called Blindsight. In it humans encounter an an alien race they call Scramblers, who can move very fast and precisely, and they exploit saccades.

Because if they only move during saccades, we never see them moving. And since so much of our vision is based on just filling in what we think is there, if they stay out of the direct center of our vision, we'll just visually fill them in, like they were never there.

Check it out if you're into hard SF stories of first contact. It's got some really neat ideas about human vision, very unique aliens, the future of humanity in the face of perfect VR, and vampires. (Really, it has "vampires", while still being hard-SF)

BTW, remember how I said "vertebrate eyes" up there? Guess who has eyes which are wired forwards instead of backwards (have no blindspot), have an internal lens, and can even see polarization of light? Our good friends the Cephalopods!

[magnetothemagnificent]

I've seen people claim "trauma changes your DNA!" or "HRT changes your DNA" (said by trans folks trying to make a point? I guess?) But...no. Sorry. That's not true.

What you're referring to is epigenetics, and it doesn't change your DNA. It just influences which genes are turned on or off, or how certain genes are expressed. Your DNA is your genetic code- epigenetics doesn't change the code, merely how it is interpreted.

For example: You could have a gene that when turned on does one thing, but you were born with it turned off. Epigenetics comes in and turns it on. Doesn't change the gene itself nor your DNA. Just how it's expressed. The gene is still the same string of base pairs, it hasn't changed.

Please stop spreading scientific and medical misinformation.

[religion-is-a-mental-illness]

By: Nathan Williams

Published: Apr 27, 2021

Pseudoscience has become a serious problem. From Covid conspiracy theories to climate change denialists, the spread of scientific misinformation threatens our health and the health of our planet. Now there’s a new pseudoscience as bogus as flat-earthism or creationism. But this time there’s something different: those who you might expect to fight against pseudoscience are turning a blind-eye — or in some cases spreading it. This is the phenomenon of sex denial: the rejection of one of the most basic facts of biology in the name of ideology.

I’ve spent much of my career fighting against pseudoscience. I worked with the legendary sceptic James Randi to debunk homeopathy; I’ve also battled climate denialists and anti-vaxxers. I know pseudoscience when I see it. Sex-denial is a classic of the genre, using all the same techniques to sow confusion and misinformation. Their target is the seemingly uncontroversial, indeed obvious, fact that humans can be female or male.

Here’s what the science says: there are only two human sexes. That’s because there are only two types of gamete (the sex cells — egg and sperm). Humans (like all mammals) can develop along one of two pathways: towards making eggs (female) and towards making sperm (male). If anyone ever finds a third sex it would be a discovery on a par with finding a new continent — with a guaranteed Nobel prize. Until you see those headlines, you can rest assured there are exactly two sexes.

A small number of people have disorders or variations in their sex development (VSDs) meaning some aspect of their anatomy or genetic makeup may be atypical. But most people with VSDs are still clearly and unambiguously male or female. Indeed, most would consider it offensive to say that just because some part of your body is atypical that you are less of a male or less of a female. In a tiny subset it can be difficult to distinguish whether someone is male or female — sometimes called intersex conditions — but these likely account for less than 0.02 per cent of births. So, the overwhelming majority of people are unequivocally female or male, with their sex fixed from before they’re born to the moment they die. None of this is remotely new or controversial (at least in science).

Biological sex exists and it matters — most obviously because the existence of the human race depends on it. You can’t make a human baby without a male and a female — yet the sex-denialists hardly ever mention reproduction. Which is odd since that’s precisely why sex exists. Sex also matters for a host of other reasons. It influences your height, weight, strength and lifespan. It determines your likelihood of getting breast cancer or testicular cancer, heart attacks, mental illness, even your chance of dying from Covid-19. Denying sex is dangerous as well as disingenuous.

So what exactly do the sex-denialists claim? Like climate-deniers or flat-earthers, there’s no single alternative theory — rather a hodge-podge of different claims designed to confuse the public and push an ideological agenda. At the most extreme there are those who flat out deny the reality of sex. “It is not correct that there is such thing as biological sex”, says Prof Nicholas Matte at the University of Toronto. Dawn Butler, a British MP and the Labour Party’s Shadow Minister for Women and Equalities, said on national television: “A child is born without sex.” What is so extraordinary about this claim is that it is so obviously untrue. At least the flat-earthers have some degree of everyday experience on their side: it’s easy to forget we’re on a spinning ball of rock. But to deny something that everyone knows and experiences every day is bizarre — and of course not supported by any science.

Another approach is to accept that the sexes exist but imply they’re a human invention, like faiths or football teams. For instance, Chase Strangio of the ACLU says, “The notion of “biological sex” was developed for the exclusive purpose of being weaponised against people.” This is a classic pseudoscience confidence trick. Of course it’s true that all scientific concepts are in one sense human creations. Mammals, atoms, temperature and earthquakes are all concepts created by scientists. However, those concepts are useful precisely because they describe real aspects of the physical world. Surely no one would claim that these exist purely in our minds. Similarly, the reality of biological sex is a fundamental fact about all mammals that existed long before humans did — just as gravity existed long before Newton.

A third approach is to accept that sex exists but claim it’s so complicated that you really shouldn’t bother your pretty little head about it. A recent article in The Skeptic took this approach — drawing an analogy between the concept of sex and the concept of species. It’s true that there are cases where the borderline between species can get fuzzy — for instance hybrid polar and grizzly bears can exist with the delightful name of pizzly bears. But such rare cases don’t invalidate the concept of species — indeed biology would be impossible without it. The overwhelming majority of vertebrate animals are members of a single species — just as most humans are members of a single sex.

Whereas most popular science articles are trying to take a complex subject and make it seem simple, articles like these strive to take a simple concept and make it seem complex. The evidence is clear in one of the most unusual corrections I’ve ever seen. “This article was updated as it previously omitted a reference to primary sexual characteristics.” That’s right — an article all about the reality of biological sex “forgot” to mention the primary sexual characteristics. This is deliberate scientific obfuscation.

So why would anyone want to deny something as important and obvious as sex? Perhaps it is the misguided belief that obscuring the reality of sex will help trans people. It is of course important to distinguish between sex and gender or gender identity (someone’s internal sense of who they are and the social roles they fulfil). There are people whose biological sex and gender identity do not match: trans people. I believe people should be free to self-identify as whatever gender they wish. However, one can no more self-identify one’s sex than you can self-identify your height.

This needn’t be a problem — we can celebrate that there are people who want to break out of the traditional roles and social expectations associated with their sex. But the new ideology says that a trans person doesn’t merely change their gender, they change their sex — even if they’ve had no surgery or hormone treatment. This means believing that someone can have a body identical to that of a typical male and yet in fact be female purely through the act of identifying as such. The only way to make that falsehood true is to demolish the very notion of biological sex.

Without the truth on their side, the sex denialists’ only option is to shut down discussion. Anyone who dares question the ideology faces insults, abuse and even violence. It’s an approach that has proven highly successful. Despite this being an issue of great public interest, very few scientists or science journalists have made any attempt to communicate what the science says. When I approached the Science Media Centre, which prides itself on being able to find scientists to talk on even the most controversial subjects, they said they were unable to provide a single expert. Places that once championed rationality and evidence like the Freethought Blog now explicitly ban those who dare present views on the existence of biological sex that they consider heretical.

When a biologist tweeted that stating biological facts is not bigotry, she was attacked by the very body you might expect to support her — The Royal Society of Biology — which labelled her comments as “transphobia”. Perhaps there was some detail of the science she got wrong — in which case you would expect this learned society to point out the error. But despite numerous attempts to find out what was incorrect about her statements, they have refused to answer. Even at its most censorious — the Catholic Church would tell blasphemers what their crime was. The modern witch-burners won’t even do that — they will rarely even discuss their claims with anyone who does not already share their beliefs.

Even one of the world’s best-known biologists isn’t safe. Prof. Richard Dawkins recently tweeted to ask whether there was a difference between self-identifying your race and self-identifying your sex/gender. This was the final straw for the American Humanist Association which duly stripped him of a 25-year-old lifetime award — something they’d only done once before when a recipient was accused of serious sexual harassment. Humanism is supposed to stand for rationality and freedom of thought, but for the AHA it seems heresy is still a crime punishable by excommunication. These are far from isolated examples. Many academics, particularly women, have faced threats and harassment merely for daring to talk about biological sex. There is no clearer demonstration that sex denialists are charlatans; their only weapons are creating fear and confusion. It’s time the rest of us stood up to them.

[thelifeofniy]

[chickenoodlesoups]

I'm a genius. I've figured out why the women in one piece don't experience organ failure or spinal collapse.

Boohyah.

[enigmaticmoonchild]

Something that really stuck with me my first year of med school was learning that women are born with all of their eggs. They won't produce any more over the course of their life, and they grew with us whilst in the womb. That just tells me that everyone has kinda been with their mom since before their moms were even born. And I find that very sweet.

[quotesfrommyreading]

One study concluded that humans have five times the information-processing capacity of cetaceans, whom they placed beneath chimps, monkeys, and some birds. But in the same study, horses—with smaller brains than chimps—were found to have five times the number of cortical neurons. Does this mean horses are smarter than chimps? A major confounding factor in these types of comparisons appears to be that every factor is itself quite confounding. Estimating numbers of neurons is a very rough science, so the raw number comparisons are crude. There are lots of different kinds of neurons, and they are arranged in different configurations and proportions in different species. We know all these variations mean something, that they will determine what brains are capable of, but we don’t know yet quite what, or how that might change from one moment to the next in different parts of the brain. There are a lot of assumptions at play, and it can be misleading to extrapolate from one brain to another.

This also applies to comparing cognitive ability. Trying to infer from brains and their structures which animals are “better” at cognition and ranking animal brains in order of “intelligence” is as treacherous as it is tempting. Stan Kuczaj, who spent his lifetime studying the cognition and behavior of different animals, put it bluntly: “We suck at being able to validly measure intelligence in humans. We’re even worse when we try to compare species.” Intelligence is a slippery concept and perhaps unmeasurable. As mentioned earlier, many biologists conceive of it as an animal’s ability to solve problems. But because different animals live in different environments with different problems, you can’t really translate scores of how well their brains perform. A brain attribute is not simply “good” or “bad” for thinking, but rather varies depending on the situation and the thinking that brain needs to undertake. Intelligence is a moving target.

What confounds this dilemma further is that individual animals within a species have varying cognitive abilities. To quote the Yosemite National Park ranger who, when asked why it was proving so hard to make a garbage can that bears couldn’t break into, said, “There is considerable overlap between the intelligence of the smartest bears and the dumbest tourists.”

 —   In the Mind of a Whale

[warcraftedtardis]

Hmm more space orcs?

Okay so,,, I rly don’t know if anybody made a post about this yet, but can we talk about the weird way human bodies just,,, Do Exercise?

I’m a healthy 240lbs ish of meat mecha, at least 20lbs of which is just fat stored on my tum; like even at my most physically active and “healthy” I was still a chonktastic 225 or so, but in all that time I’ve been doing the whole diet and exercise rigamarole I noticed a Thing My Body Does. This bastard HATES being worked like a draft horse. Like he viscerally does Not want to Do The Thing UNTIL he’s been compelled into the thing for like 10 or so minutes.

After about 10 for cardio and 15 for any muscle work, the human body (or at least my body) decides it likes this activity actually and will just keep Doing The Thing until something else compels it to stop. Like,,, is this just me or do other ppl experience the pursuit predator brain kicking in?

Like, logically it makes sense that humans are still adapted to being pursuit predators slowly terminatoring their way after their food, but it rly doesn’t hit you that fundamentally you today are the same animal that stalked prey for miles endlessly until The Thing happens.

So, humans as a species can hit this grove of motion where once the body gets a stride at a comfortable, personal speed, they can just go virtually indefinitely. Pursuit predation is not the most common method for carnivorous or omnivorous animals to obtain meals. Yeah humans don’t have the same top speed as another highly successful pursuit predator like the hyena, but unlike the hyena we can throw shit really accurately from long distances. I don’t need to sprint after my food if I’ve got a bunch of carved, pointy sticks and a whole day to kill. Calorically, a slow persistent jog or fast walk is much more energy efficient than a full sprint anyway.

Like, fuck, the reason we find the Slasher walk scary is because humans have an instinct for that same method of hunting.

TL;DR So basically The Thing were your body just clicks with physical effort and the walking/jogging experience is no longer a chore but just a way to be is the voice of your ancestors connecting you to your pursuit predator nature. They are cheering you on in the never ending marathon of human evolution. If you can, and it won’t exacerbate any chronic illness or pain, you should just Move and Do. It’s rly nice to feel yourself hit your own stride tbh.

[haggishlyhagging]

The way men construct the world to enhance their image of themselves (appropriating women's resources and denying women's being in the process) is explored at some (satirical) length by [Ruth] Herschberger. One section of her book is entitled ‘Patriarchal Society Writes Biology’ and in it she outlines the definitions and theories with which we are familiar, and in which men have interpreted phenomena to provide themselves with a favoured place. But then she has a section entitled ‘Matriarchal Society Writes Biology’ in which she provides alternative definitions and theories, in which women are provided with a favoured place, and the contrast is dramatic.

Having given a customary account of the development of the embryo, from a male point of view, in which the male embryo is the positive norm, Herschberger proceeds to describe the embryo and its development from a woman's point of view: ‘The male, we find, does not develop in any important way from the asexual or early embryonic state,’ she writes. ‘His sexual organs remain in an infantile condition, displaying an early arrest of development’ (ibid., p. 79). This amounts to ‘outrageous distortion’ because it reserves ‘activity’ for the female and reduces the male to a 'passive' and ‘invisible’ state, and Herschberger continues with other 'outrageous distortions' along the same lines. ‘The male sperm’, she says, ‘is produced in superfluously great numbers since the survival of any one sperm or its contact with an egg is so hazardous and indeed, improbable. The egg, being more resilient, and endowed with solidity, toughness, and endurance, can be produced singly and yet effect reproduction’ (ibid., p. 82).

The world looks very different when female imagery is invested with centrality, visibility, and strength. ‘After the sperm are drawn into the vicinity of the egg,’ she states, appropriating for female the motion of the sperm, in exactly the same way that males have appropriated female activity for themselves in the past, ‘the egg by some little known mechanism selects one cell from the many present. Sometimes none of the sperm suits the egg, in which case there is no fertilization’ (ibid., p. 84). It is not the (usual) active, daring, venturesome little sperm that goes off to transform a passive egg, that we see here, but a central, strong, independent and selective egg that surveys the offerings it has commanded, and sometimes chooses not to have anything to do with any of them. Herschberger's point is that one description is no more valid, at this stage, than the other.

-Dale Spender, Women of Ideas and What Men Have Done to Them

[reasonsforhope]

This is maybe an odd thing to put on a good news/reasons for hope blog, but I've also had people tell me that they find this info really, genuinely comforting, so I'm putting it up. Also, further understanding could do a ton to advance medicine, esp. re: allergies, autoimmune diseases, and depression. You can read more about this at the link.

"More than half of your body is not human, say scientists.

Human cells make up only 43% of the body's total cell count. The rest are microscopic [co-contributors].

Understanding this hidden half of ourselves - our microbiome - is rapidly transforming understanding of diseases from allergy to Parkinson's.

The field is even asking questions of what it means to be "human" and is leading to new innovative treatments as a result.

"They are essential to your health," says Prof Ruth Ley, the director of the department of microbiome science at the Max Planck Institute, "your body isn't just you."

No matter how well you wash, nearly every nook and cranny of your body is covered in microscopic creatures.

This includes bacteria, viruses, fungi and archaea (organisms originally misclassified as bacteria). The greatest concentration of this microscopic life is in the dark murky depths of our oxygen-deprived bowels.

Prof Rob Knight, from University of California San Diego, told the BBC: "You're more microbe than you are human."

Originally it was thought our cells were outnumbered 10 to one.

"That's been refined much closer to one-to-one, so the current estimate is you're about 43% human if you're counting up all the cells," he says.

But genetically we're even more outgunned.

The human genome - the full set of genetic instructions for a human being - is made up of 20,000 instructions called genes.

But add all the genes in our microbiome together and the figure comes out between two and 20 million microbial genes.

Prof Sarkis Mazmanian, a microbiologist from Caltech, argues: "We don't have just one genome, the genes of our microbiome present essentially a second genome which augment the activity of our own.

"What makes us human is, in my opinion, the combination of our own DNA, plus the DNA of our gut microbes."

It would be naive to think we carry around so much microbial material without it interacting or having any effect on our bodies at all.

Science is rapidly uncovering the role the microbiome plays in digestion, regulating the immune system, protecting against disease and manufacturing vital vitamins.

Prof Knight said: "We're finding ways that these tiny creatures totally transform our health in ways we never imagined until recently."

It is a new way of thinking about the microbial world. To date, our relationship with microbes has largely been one of warfare.

-via BBC News, April 10, 2018

[er-cryptid]

Human corneas are incredibly similar to shark corneas

[turquoiseeyesandsilverskies]

Day 2 of 100 days of productivity

°• Went through important topics in biochem and anat

°• Watched videos to cover topics in reproductive and endocrine Physiology that I didn't have the energy to read through

Kinda starting to get concerned if I can finish revising everything before the models,but thankfully there's a full month left till the uni finals lol, so yayy?

Days left until the Model exams :4

[stone-cold-groove]

The human heart, apparently unbroken.