what is stem cell research

stem cells we hear a lot aboutstem cells these days, but what are they,where do they come from and what do we reallyknow about them? inside our bodiesthere's a microscopic world, busy and complexlike the world around us. stem cells buildand maintain this world. this is a story of stem cellsand their lives inside and outside our bodies.

life begins with one cell,the fertilised egg. throughout developmentcells divide over and over again to produce the billionsof cells that make up the body. at certain stages, most cellsstop making copies of themselves and start to specialise. when we are fully formedalmost all our cells are specialised. cells are beautiful thingswhen you see them down a microscope. normally they're so minisculewe can't see them, even though they'rewhat make us.

and each type of cellhas its own characteristic. some types of cellgrow very closely together and form beautiful patterns. other types of cellwill move away from one and other. some cells become big,others are always very small. it depends on what type of cell they are. these different cell typeswork in specialised teams. some carry oxygenthrough the blood system, some do the stretchingand contracting in our muscles,

some carry messages between our brainand the rest of our body. stem cells are very special cellsthey act as a resevoir, because the specialised cells can no longer make copies of themselves. so, if they die and get used up,they have to be replaced from somewhere. and this is where the stem cells function. stem cells are usedin the blood system. we need to make millionsof new blood cells every day and these are generatedfrom stem cells.

and these cells actually livein the bone marrow. altogether a blood stem cellcan make eight different types of specialised cell. they're used in the skin. we need to make new skin cellsall the time because we're alwayswearing away our skin. and actually now we knowthey're present even in the brain. we always have to makenew stem cells, so they're not completely exhausted,

because otherwise we'd losethe capacity to make any new cells. so the stem cell has tomake a decision. every time it divides,it produces two daughter cells, and those daughter cellscan be new stem cells, or they can be specialised cells. stem cells in the adult tissuescan normally only make the type of cell in that tissue. so a stem cell in the skin,can make cells in the skin, but it can't make blood cellsand vice versa.

stem cells are already usefulin medicine. one skin stem cell alone can produceenough specialised skin stells to cover the whole body. this produced a breakthroughin the treatment of extensive burns. 1st degree burn... when a person is heavily burnt,we take a sample from an unburnt areaand we take apart the skin sample and we get the cells out of it, and we seed the cellsin a culture flask like this one.

we feed the cells with a special liquid,which is full of protein and sugar. they need to eat like you. at some point, these cells will divide,will multiply. and they will cover the entirebottom of the flask. we remove the cells usinga special chemical and we take this sheet of cellsinto the surgery room and transplant the patient with it. we can do only part of the skin today, which means we can dothe outer most layer of the skin,

which is very important, because withoutthis layer you wouldn't be able to survive. however, we cannot reconstructsweat glands our hair follicles. so these burnt patients have hadtheir lives saved by stem cells, but they have no hairand they don't sweat. that is obviously a problem. they are alive, but i can't saythey have a normal life. that's why many laboratoriesare trying to understand how the skin is built to be ableto reconstruct it in the lab, so we can improve the lifeof these patients.

stem cells are also used to treatpatients with blood disorders, such as leukaemia. a transplant of justa few blood stem cells, is enough to repairthe entire blood system. stem cells for specific tissuesand organs can only make the cellsof that tissue. we know there are stem cellsin skin, blood, guts and muscles, but we don't know whetherother organs have their own stem cells, or how useful they will be.

back along the chain of development,there's another kind of stem cell. it's controversial. it can becomeany specialised cell. the embryonic stem cell. this cell comes from a blastocyst,the stage of development before implantation in the uterus. for fertility treatment, blastocysts areproduced in the laboratory. if they are not used for a pregnancy,they can be donated for research. in the early embryo,there's a group of cells that can give rise toall the tissues of the body.

these are the cellswe're very interested in because we know that we cantake the cells from the early embryo and grow them in culture,and maintain them in a state where they can contributeto all the tissues. what we're seeing hereis the blastocyst stage of development. it's smaller than a pin head. you can't see it withoutthe microscope. so at this stage, the cellsin the embryo - these are the cells - they can make any tissue at all.

what we have to do, is isolate these cells. one way is we can removethe trophectoderm cells so that we're just left with a cleaninner cell mass. so we can grow these in culture,and they'll multiply until we have lots of these cells that still have the capacity to form any tissue at all. embryonic stem cells can becomeheart, blood, brain or skin cells depending on the way they are grown.

these stem cells haveturned into heart cells. when you're working with stem cells,you're always observing the cells and you're trying to understandhow it is they can do what they can do. you're trying, actually, to make them dowhat you want to do. it's almost like a battle of wills. a stem cell goes through a long series of decisions to become a specialised cell. a combination of internal and externalsignals guide each stem cell along the path towards specialisation.

these signals are normallyprovided by the body. by figuring out how to recreatethese signals in the lab, scientists aim to grow pure populationsof almost any cell type. the challenge to us is to understandeach decision and how it's controlled. and then how to provide those signals, to impose the direction on the sytem. and once we get to a pointwhere that begins to happen, then you suddenly see thatyou could use it to address medical conditionsand problems.

work that we havebeen doing recently has been focussed on tryingto make stem cells for the brain from embryonic stem cells.and it turns out we're able to do this. these neural stem cellsare now no longer able to make all cells, they can only make three types of cells,the three types that exist in the brain. so this is an important first stepin creating a useful and powerful system, that can both be applied for drug screeningand perhaps in the end for transplantation. these lab-grown human cells,produced in large numbers, provide improved modelsfor testing new medical treatments

and may reducethe need for animal testing. the same cells may help us understandwhat goes wrong in complex diseases, like alzheimer's, parkinson'sand diabetes. diabetes is a chronic diseasedefined by high blood sugar levels that stay high just becausethere is not enough insulin. we know that the insulin is produced bycells in the pancreas. we call them beta cells. transplantations of those cellsare now done in clinics. those cells are isolated fromdonor organs.

after transplantation with those cells,you can normalise diabetes. you can correct diabetes. the major obstacle to beta celltransplantation in diabetes is the shortage of donor cells. we can transplantonly 25 patients per year, while there are more than 50,000 patientsin belgium that are treated with insulin. we have to look for other techniques to produce insulin-making cellsin the laboratory. what the researchers try to do

is first examine this path,this evolution between the embryonic stem celland the insulin-producing beta cell, and then to also try to isolatethe different stages, the different kind of stem cellson the way to beta cells. if one can then isolate themand let them grow in the laboratory then you can make as manyinsulin-producing cells as you want. and that's the goalof many investigators in the world. the embryonic stem cell areais a very exciting area. it really has opened a new world,that of regenerative medicine.

we have now bridges betweenall the laboratories that have a particular expertise. working together,we will be in a good position to examine, to investigateits enormous potential, but the enthusiasm should not coverall the technical and scientific questions and obstacles that exist and that will haveto be studied very carefully. stem cell research is a fast-moving field. around the world,new findings are constantly reported,

creating new questionsand fresh challenges for scientists seeking to harness these cellsand to shape future medicine. so cells are the building blocksof the tissues and organs of the body. and many people are interested in this. what captured my imagination,was when i realised that in development, cells actuallyhave to make choices and decide to becomedifferent types of cell, and understanding how that is controlled,how that decision is made... if you could understand that,it seems to me,

then you would understandthe most important thing about life.

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what is meant by stem cell

can you imagine a world where one day if youneed a new heart you could just order one made just for you? sound like science fiction?well we’re not so far off. hey guys, julia here for dnews dudes, so something pretty cool just happenedin the wonderful world of science. researchers grew beating hearts from human stem cells.okay fine hyperbole, it’s not the whole heart just a few beating cells. but it’sso cool. in a study published in the journal nature,the researchers used human skin cells, turned them into pluripotent cells and used physicaland chemical signals to coax the cells into forming little cardiac microchambers. whichcould be important for studying how the heart

grows in an embryo or how drugs might affecta fetus’s heart. or… looking way into the future, for growing hearts in a dish.it could be a great way to replace organs. no more waiting for a donor and since it wouldbe perfect match to your body, no more terrible drugs to prevent rejection.so far smaller organs like tracheas and bladders have been grown in a lab using a person’sown stem cells, but a heart is a little more complicated. so let’s take a little lookinto how we got here. first off, what are stem cells? stem cellsare pluripotent, meaning they are undifferentiated cells that can develop into any kind of cell.skin, heart, liver etc. so alright, but what’s the big deal? why do researchers love to studystem cells? even from the earliest inklings

of stem cells, there have been big dreams.researchers have hoped that one day they could be able to grow entire new organs from stemcells that would be a perfect match for the recipient. we’ve come a long way from the early daysof stem cell research. human stem cells were first isolated in 1998 by two independentresearch teams led by james a. thomson of the university of wisconsin and another byjohn d. gearhart of johns hopkins university school of medicine. these early stem celllines were derived from early embryos, which are destroyed in the process and thus stirreda little controversy. okay a lot of controversy. because of the debate that raged in the ussurrounding embryonic stem cell research,

scientists looked to find stem cells in otheradult tissues. so a few years later in 2001 adult stem cells were found in fat tissue.now adult stem cells can be found from almost any tissue. but they are tricky, they takea while to coax into growing in a dish. so they’re not ideal. but in 2007, in a paper published in the journalnature biotechnology, dr. anthony alata discovered that amniotic fluid also contains stem cells.which of course added more fuel to the debate. and the same year, two independent teams ofresearchers pioneered a process to turn adult somatic cells into pluripotent stem cells,naturally called induced pluripotent stem cells. the process involves introducing 4different genes into the cells using a virus

as a carrier. the team from japan led shinya yamanaka, publishedtheir work in the journal cell and the team from by james thomson at university of wisconsin–madisonpublished their work in the journal nature. and it was such a huge deal that, yamanakaactually won the 2012 nobel prize for discovering ips cells. which of course this discovery held a lotof promise, it would sidestep some of the controversy with embryonic stem cells. butthere are more than a few issues with their technique, like low efficiency, it’s difficultto do and when done, only a few cells are reprogrammed. plus there’s weird problemswith rejection and also a problem with tumors

developing. but problems aside, tons of studies have beenand are being done with this technology. with lofty goals, like attempting to cure blindnessand diabetes. the federation of american societies for experimental biology says that ips cellswill also “allow scientists to study complex human diseases in petri dishes, a step towardanalyzing the conditions and developing therapies.” some researchers like dr. alata don’t carewhere the cells come from, just that they work well. no matter where stem cells comefrom, it’s clear that we’re on the road to organs grown in a dish. well i certainlyhope so. but it’s also clear that more research is needed.

and really, lab grown organs can’t comesoon enough! if you wanna know the challenges of living with an organ transplant & why theyfail, check out this recent video i did:

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what is embryonic stem cell research

hello, you've reached placidway, the leadinghealth tourism company where you can compare the most affordable treatments worldwide!subscribe to our youtube channel and get instant access to all of our latest health videos.embryonic stem cell therapy embryonic stem cells are derived from embryonictissues. in most cases, embryonic stem cells are created or procured from embryos thathave been developed from eggs fertilized through in-vitro fertilization procedures, but whatmost people don't know or realize is that many of them are donated for research purposeswith informed consent of the donors. it should be stated unequivocally that embryonic stemcells are not taken from eggs fertilized within a woman's body.embryonic stem cell research

embryonic stem cell research will more thanlikely continue to be embroiled in moral and ethical debates regardless of the fact thatresearching and studying their potential for health and medical research may very wellprovide treatments and cures for disease processes such as alzheimer's, parkinson's,leukemia,other cancers, and forms of diabetes. embryonic stem cell research & treatment ofhuman diseases embryonic stem cell research has been usedfor the treatment of human diseases for many years. since the late 1990s, the universityof wisconsin, among other stem cell research facilities in the united states and aroundthe world, have developed techniques to isolate and grow certain types of stem cells for medicalresearch.the potential of embryonic, adult

stem cell, placenta and umbilical cord stemcells in the treatment of human illnesses and disease processes including diabetes,kidney disease, cancers, mental disease processes such as parkinson's and alzheimer's, as wellas in cardiac care, and spinal cord injury treatment is unlimited. if you want to know more, contact us.

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what is a stem

how do we get around from place to place without having to walk everywhere? how can we communicate with people who live far away? these were problems that people struggled with for a long time, until recently. before there were things like cars, and phones, and computers. and you know who solved those problems? engineers. but do you know what an engineer is? the short answer is that an engineer is someone who wants to know how and why things work. now, i want to know how and why things work, but does that make me an engineer? not quite. besides being naturally curious, an engineer is a person who designs and builds things like machines

or systems, or structures, that help solve a specific problem. there's more than just one type of engineer, too. but no matter what type of engineer someone is, they have to ask themselves three very important questions when they're working. 1. what is the problem that needs to be solved? 2. who has the problem that needs to be solved? and most importantly 3. why is this problem important to solve? let's take a look at some examples.

a really famous example of engineering is the golden gate bridge in san francisco, california. i mentioned that there are different kinds of engineers, and the civil engineer is someone who designs and constructs buildings, roads and, yep, bridges for the person who designed the golden gate bridge, what was the problem that they needed to solve? people couldn't travel in or out of san francisco, which is surrounded on most sides by water, without a boat. who had the problem? residents of san francisco, mostly, but really anybody traveling in the area. why was the problem important to solve? well you didn't want a whole bunch of san fransisco residents trapped in san fransisco forever.

even if it's a super cool city. plus you wanted people outside of san fransisco to be able to travel to the city easily if they needed to. so the golden gate bridge was engineered as a solution to this problem in addition to civil engineers, there are also mechanical, electrical, chemical, computer, nuclear, and software engineers. and the list goes on let's talk about what some of the other types of engineers do. first up, electrical engineers. electrical engineers study electricity. they design electrical systems like circuits and computer chips. think of an electrical object that you use pretty regularly. how about your microwave? what problem was the microwave a solution to?

cold food, right? you have an electrical engineer to thank for the ability to reheat that leftover pizza you just had for lunch. but while you might not have heard of joseph strauss or percy spencer, the engineers responsible for the golden gate bridge and the microwave respectively, you`ve probably heard of henry ford. as in ford cars. henry ford was a mechanical engineer, or someone working in a manufacturing industry, making mechanical things like tools, engines and machines. machines like cars. ford didn`t invent the automobile, but his ford motor company made a lot of them.

his model t car was famous for being affordable for plenty of americans. ford saw that lots of people who wanted to drive cars, just couldn`t. because they couldn`t afford the pricey vehicles that were for sale. so he engineered a cheaper model as a solution to this problem. his fellow engineers started to do the same and now, well, car are everywhere. henry ford`s was not the only big name engineer. a famous engineer around today is marissa mayer. mayer is the president of the internet company yahoo, and is also a software engineer. software engineers work on computers and other products that use software to write programs to make them faster and able to do more things.

no matter what kind of engineer someone is, their job at it`s most basic level is problem-solving. each engineer just specializes in solving certain kinds of problems. while it might seem like there are too many types of engineers to keep track of, just wait 15 years, or 50, or 100. because we will probably have a ton of different types to add to the list by then. think about it. over a 100 years ago we didn`t have jobs in fields like aerospace engineering where people design and construct planes and spacecraft. we didn`t have planes like we do today, or need spaceships. so we didn`t need people to engineer them.

who knows what machines or tools or everyday objects we will have in the year 3015? personally, i`m hoping for underwater cities. but whatever these things are, we will need engineers to make them. so what do you say? who wants to be an engineer?

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what is a stem cell

where we left off after themeiosis videos is that we had two gametes. we had a sperm and an egg. let me draw the sperm. so you had the sperm andthen you had an egg. maybe i'll do the egg ina different color. that's the egg, and we allknow how this story goes. the sperm fertilizes the egg. and a whole cascade of eventsstart occurring.

the walls of the egg then becomeimpervious to other sperm so that only one sperm canget in, but that's not the focus of this video. the focus of this video is howthis fertilized egg develops once it has become a zygote. so after it's fertilized, youremember from the meiosis videos that each of these werehaploid, or that they had-- oh, i added an extra i there--that they had half the contingency of the dna.

as soon as the sperm fertilizesthis egg, now, all of a sudden, you havea diploid zygote. let me do that. so now let me picka nice color. so now you're going to have adiploid zygote that's going to have a 2n complement of the dnamaterial or kind of the full complement of what a normalcell in our human body would have. so this is diploid,and it's a zygote, which is just a fancy way ofsaying the fertilized egg.

and it's now readyto essentially turn into an organism. so immediately afterfertilization, this zygote starts experiencing cleavage. it's experiencing mitosis,that's the mechanism, but it doesn't increasea lot in size. so this one right here will thenturn into-- it'll just split up via mitosisinto two like that. and, of course, these are each2n, and then those are going

to split into four like that. and each of these have the sameexact genetic complement as that first zygote, andit keeps splitting. and this mass of cells, we canstart calling it, this right here, this is referredto as the morula. and actually, it comes from theword for mulberry because it looks like a mulberry. so actually, let me just kindof simplify things a little bit because we don'thave to start here.

so we start with a zygote. this is a fertilized egg. it just starts duplicating viamitosis, and you end up with a ball of cells. it's often going to be a powerof two, because these cells, at least in the initial stagesare all duplicating all at once, and then youhave this morula. now, once the morula gets toabout 16 cells or so-- and we're talking aboutfour or five days.

this isn't an exact process--they started differentiating a little bit, where the outercells-- and this kind of turns into a sphere. let me make it a littlebit more sphere like. so it starts differentiatingbetween-- let me make some outer cells. this would be a cross-sectionof it. it's really going to lookmore like a sphere. that's the outer cells and thenyou have your inner cells

on the inside. these outer cells are calledthe trophoblasts. let me do it in adifferent color. let me scroll over. i don't want to go there. and then the inner cells, andthis is kind of the crux of what this video is allabout-- let me scroll down a little bit. the inner cells-- picka suitable color.

the inner cells right there arecalled the embryoblast. and then what's going to happenis some fluid's going to start filling in someof this gap between the embryoblast and the trophoblast,so you're going to start having some fluid thatcomes in there, and so the morula will eventuallylook like this, where the trophoblast, or the outermembrane, is kind of this huge sphere of cells. and this is all happening asthey keep replicating.

mitosis is the mechanism, so nowmy trophoblast is going to look like that, and thenmy embryoblast is going to look like this. sometimes the embryoblast-- sothis is the embryoblast. sometimes it's also called theinner cell mass, so let me write that. and this is what's going toturn into the organism. and so, just so you know acouple of the labels that are involved here, if we're dealingwith a mammalian

organism, and we are mammals,we call this thing that the morula turned into is a zygote,then a morula, then the cells of the morula startedto differentiate into the trophoblast, or kind of theoutside cells, and then the embryoblast. and then youhave this space that forms here, and this is just fluid,and it's called the blastocoel. a very non-intuitive spellingof the coel part of but once this is formed, this iscalled a blastocyst. that's

the entire thing right here. let me scroll downa little bit. this whole thing is called theblastocyst, and this is the case in humans. now, it can be a very confusingtopic, because a lot of times in a lot of books onbiology, you'll say, hey, you go from the morula tothe blastula or the blastosphere stage. let me write those words down.

so sometimes you'll say morula, and you go to blastula. sometimes it's calledthe blastosphere. and i want to make it veryclear that these are essentially the same stagesin development. these are just for-- you know,in a lot of books, they'll start talking about frogs ortadpoles or things like that, and this applies to them. while we're talking aboutmammals, especially the ones

that are closely relatedto us, the stage is the blastocyst stage, and the realdifferentiator is when people talk about just blastulaand blastospheres. there isn't necessarily thisdifferentiation between these outermost cells and theseembryonic, or this embryoblast, or this innercell mass here. but since the focus of thisvideo is humans, and really that's where i wanted to startfrom, because that's what we are and that's what'sinteresting, we're going to

focus on the blastocyst. now, everything i've talkedabout in this video, it was really to get to this point,because what we have here, these little green cells thati drew right here in the blastocysts, this inner cellmass, this is what will turn into the organism. and you say, ok, sal, if that'sthe organism, what's all of these purplecells out here? this trophoblast out there?

that is going to turn into theplacenta, and i'll do a future video where in a human, it'llturn into a placenta. so let me write that down. it'll turn into the placenta. and i'll do a whole future videoabout i guess how babies are born, and i actually learneda ton about that this past year because a babywas born in our house. but the placenta is reallykind of what the embryo develops inside of, and it's theinterface, especially in

humans and in mammals, betweenthe developing fetus and its mother, so it kind of is theexchange mechanism that separates their two systems,but allows the necessary functions to go onbetween them. but that's not the focusof this video. the focus of this video is thefact that these cells, which at this point are-- they'vedifferentiated themselves away from the placenta cells, butthey still haven't decided what they're going to become.

maybe this cell and itsdescendants eventually start becoming part of the nervoussystem, while these cells right here might become muscletissue, while these cells right here might becomethe liver. these cells right here arecalled embryonic stem cells, and probably the first time inthis video you're hearing a term that you might recognize. so if i were to just take one ofthese cells, and actually, just to introduce you to anotherterm, you know, we

have this zygote. as soon as it starts dividing,each of these cells are called a blastomere. and you're probably wondering,sal, why does this word blast keep appearing in this kindof embryology video, these development videos? and that comes from the greekfor spore: blastos. so the organism is beginningto spore out or grow. i won't go into the word originsof it, but that's

where it comes from and that'swhy everything has this blast in it. so these are blastomeres. so when i talk what embryonicstem cells, i'm talking about the individual blastomeresinside of this embryoblast or inside of this innercell mass. these words are actuallyunusually fun to say. so each of these is anembryonic stem cell. let me write this downin a vibrant color.

so each of these right here areembryonic stem cells, and i wanted to get to this. and the reason why these areinteresting, and i think you already know, is that there'sa huge debate around these. one, these have the potentialto turn into anything, that they have this plasticity. that's another word thatyou might hear. let me write that down,too: plasticity. and the word essentially comesfrom, you know, like a plastic

can turn into anything else. when we say that something hasplasticity, we're talking about its potentialto turn into a lot of different things. so the theory is, and there'salready some trials that seem to substantiate this, especiallyin some lower organisms, that, look, if youhave some damage at some point in your body-- let medraw a nerve cell. let me say i have a-- i won'tgo into the actual mechanics

of a nerve cell, but let's saythat we have some damage at some point on a nerve cell rightthere, and because of that, someone is paralyzedor there's some nerve dysfunction. we're dealing with multiplesclerosis or who knows what. the idea is, look, we have thesecell here that could turn into anything, and we'rejust really understanding how it knows what to turn into. it really has to look at itsenvironment and say, hey, what

are the guys around me doing,and maybe that's what helps dictate what it does. but the idea is you take thesethings that could turn to anything and you put them wherethe damage is, you layer them where the damage is, andthen they can turn into the cell that they needto turn into. so in this case, they wouldturn into nerve cells. they would turn to nerve cellsand repair the damage and maybe cure the paralysisfor that individual.

so it's a huge, exciting areaof research, and you could even, in theory, grownew organs. if someone needs a kidneytransplant or a heart transplant, maybe in the future,we could take a colony of these embryonic stem cells. maybe we can put them in sometype of other creature, or who knows what, and we can turn itinto a replacement heart or a replacement kidney. so there's a huge amountof excitement about

what these can do. i mean, they could cure a lot offormerly uncurable diseases or provide hope for alot of patients who might otherwise die. but obviously, there'sa debate here. and the debate all revolvesaround the issue of if you were to go in here and try toextract one of these cells, you're going to killthis embryo. you're going to kill thisdeveloping embryo, and that

developing embryo hadthe potential to become a human being. it's a potential that obviouslyhas to be in the right environment, and it hasto have a willing mother and all of the rest, but it doeshave the potential. and so for those, especially, ithink, in the pro-life camp, who say, hey, anything that hasa potential to be a human being, that is life and itshould not be killed. so people on that side of thecamp, they're against the

destroying of this embryo. i'm not making this video totake either side to that argument, but it's a potentialto turn to a human being. it's a potential, right? so obviously, there's a hugeamount of debate, but now, now you know in this video whatpeople are talking about when they say embryonic stem cells. and obviously, the next questionis, hey, well, why don't they just call them stemcells as opposed to embryonic

stem cells? and that's because in all of ourbodies, you do have what are called somatic stem cells. let me write that down. somatic or adults stem cells. and we all have them. they're in our bone marrow tohelp produce red blood cells, other parts of our body, but theproblem with somatic stem cells is they're not as plastic,which means that they

can't form any type of cellin the human body. there's an area of researchwhere people are actually maybe trying to make them moreplastic, and if they are able to take these somatic stemcells and make them more plastic, it might maybe killthe need to have these embryonic stem cells, althoughmaybe if they do this too good, maybe these will havethe potential to turn into human beings as well,so that could become a debatable issue.

but right now, this isn't anarea of debate because, left to their own devices, a somaticstem cell or an adult stem cell won't turn intoa human being, while an embryonic one, if it isimplanted in a willing mother, then, of course, it will turninto a human being. and i want to make one sidenote here, because i don't want to take any sides on thedebate of-- well, i mean, facts are facts. this does have the potentialto turn into a human being,

but it also has the potentialto save millions of lives. both of those statements arefacts, and then you can decide on your own which side of thatargument you'd like to or what side of that balance youwould like to kind of put your own opinion. but there's one thing i wantto talk about that in the public debate is neverbrought up. so you have this notion of whenyou-- to get an embryonic stem cell line, and when i saya stem cell line, i mean you

take a couple of stem cells, orlet's say you take one stem cell, and then you put it in apetri dish, and then you allow it to just duplicate. so this one turns into two,those two turn to four. then someone could take one ofthese and then put it in their own petri dish. these are a stem cell line. they all came from one uniqueembryonic stem cell or what initially was a blastomere.

so that's what they calla stem cell line. so the debate obviously is whenyou start an embryonic stem cell line, you aredestroying an embryo. but i want to make the pointhere that embryos are being destroyed in other processes,and namely, in-vitro fertilization. and maybe this'll be my nextvideo: fertilization. and this is just the notion thatthey take a set of eggs out of a mother.

it's usually a couple that'shaving trouble having a child, and they take a bunch ofeggs out of the mother. so let's say they takemaybe 10 to 30 eggs out of the mother. they actually perform a surgery,take them out of the ovaries of the mother, and thenthey fertilize them with semen, either it might comefrom the father or a sperm donor, so then all of thesebecomes zygotes once they're fertilized with semen.

so these all become zygotes,and then they allow them to develop, and they usually allowthem to develop to the blastocyst stage. so eventually all of theseturn into blastocysts. they have a blastocoel inthe center, which is this area of fluid. they have, of course, theembryo, the inner cell mass in them, and what they do is theylook at the ones that they deem are healthier or maybethe ones that are at least

just not unhealthy, and they'lltake a couple of these and they'll implant these intothe mother, so all of this is occurring in a petri dish. so maybe these four look good,so they're going to take these four, and they're going toimplant these into a mother, and if all goes well, maybe oneof these will turn into-- will give the couple a child. so this one will develop andmaybe the other ones won't. but if you've seen john & kateplus 8, you know that many

times they implant a lot ofthem in there, just to increase the probability thatyou get at least one child. but every now and then, theyimplant seven or eight, and then you end up witheight kids. and that's why in-vitrofertilization often results in kind of these multiplebirths, or reality television shows on cable. but what do they do with allof these other perfectly-- well, i won't say perfectlyviable, but these are embryos.

they may or may not be perfectlyviable, but you have these embryos that have thepotential, just like this one right here. these all have the potentialto turn into a human being. but most fertility clinics,roughly half of them, they either throw these away,they destroy them, they allow them to die. a lot of these are frozen, butjust the process of freezing them kills them and then bondingthem kills them again,

so most of these, the process ofin-vitro fertilization, for every one child that has thepotential to develop into a full-fledged human being, you'reactually destroying tens of very viable embryos. so at least my take on it isif you're against-- and i generally don't want to take aside on this, but if you are against research that involvesembryonic stem cells because of the destruction of embryos,on that same, i guess, philosophical ground, youshould also be against

in-vitro fertilization becauseboth of these involve the destruction of zygotes. i think-- well, i won't talkmore about this, because i really don't want to take sides,but i want to show that there is kind of an equivalencehere that's completely lost in this debateon whether embryonic stem cells should be used becausethey have a destruction of embryos, because you'redestroying just as many embryos in this-- well, i won'tsay just as many, but

you are destroying embryos. there's hundreds of thousands ofembryos that get destroyed and get frozen and obviouslydestroyed in that process as well through this in-vitrofertilization process. so anyway, now hopefully youhave the tools to kind of engage in the debate around stemcells, and you see that it all comes from what welearned about meiosis. they produce these gametes. the male gamete fertilizesa female gamete.

the zygote happens or getscreated and starts splitting up the morula, and then itkeeps splitting and it differentiates into theblastocyst, and then this is where the stem cells are. so you already know enoughscience to engage in kind of a very heated debate.

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what is a stem cell research

imagine two people are listening to music. what are the odds that they are listening to the exact same playlist? probably pretty low. after all, everyone has very different tastes in music. now, what are the odds that your body will need the exact same medical care and treatment

as another person's body? even lower. as we go through our lives, each of us will have very different needs for our own healthcare. scientists and doctors are constantly researching ways to make medicine more personalized. one way they are doing this is by researching stem cells.

stem cells are cells that are undifferentiated, meaning they do not have a specific job or function. while skin cells protect your body, muscle cells contract, and nerve cells send signals, stem cells do not have any specific structures or functions. stem cells do have the potential to become all other kinds of cells in your body. your body uses stem cells

to replace worn-out cells when they die. for example, you completely replace the lining of your intestines every four days. stem cells beneath the lining of your intestines replace these cells as they wear out. scientists hope that stem cells could be used to create a very special kind of personalized medicine in which we could replace your own body parts with, well, your own body parts.

stem cell researchers are working hard to find ways in which to use stem cells to create new tissue to replace the parts of organs that are damaged by injury or disease. using stem cells to replace damaged bodily tissue is called regenerative medicine. for example, scientists currently use stem cells to treat patients with blood diseases

such as leukemia. leukemia is a form of cancer that affects your bone marrow. bone marrow is the spongy tissue inside your bones where your blood cells are created. in leukemia, some of the cells inside your bone marrow grow uncontrollably, crowding out the healthy stem cells that form your blood cells. some leukemia patients can receive

a stem cell transplant. these new stem cells will create the blood cells needed by the patient's body. there are actually multiple kinds of stem cells that scientists can use for medical treatments and research. adult stem cells or tissue-specific stem cells are found in small numbers in most of your body's tissues.

tissue-specific stem cells replace the existing cells in your organs as they wear out and die. embryonic stem cells are created from leftover embryos that are willingly donated by patients from fertility clinics. unlike tissue-specific stem cells, embryonic stem cells are pluripotent. this means that they can be grown

into any kind of tissue in the body. a third kind of stem cells is called induced pluripotent stem cells. these are regular skin, fat, liver, or other cells that scientists have changed to behave like embryonic stem cells. like embryonic stem cells, they, too, can become any kind of cell in the body. while scientists and doctors hope to use

all of these kinds of stem cells to create new tissue to heal your body, they can also use stem cells to help understand how the body works. scientists can watch stem cells develop into tissue to understand the mechnanisms that the body uses to create new tissue in a controlled and regulated way. scientists hope that with more research,

they can not only develop specialized medicine that is specific to your body but also better understand how your body functions, both when it's healthy and when it's not.

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what does stem cell mean

where we left off after themeiosis videos is that we had two gametes. we had a sperm and an egg. let me draw the sperm. so you had the sperm andthen you had an egg. maybe i'll do the egg ina different color. that's the egg, and we allknow how this story goes. the sperm fertilizes the egg. and a whole cascade of eventsstart occurring.

the walls of the egg then becomeimpervious to other sperm so that only one sperm canget in, but that's not the focus of this video. the focus of this video is howthis fertilized egg develops once it has become a zygote. so after it's fertilized, youremember from the meiosis videos that each of these werehaploid, or that they had-- oh, i added an extra i there--that they had half the contingency of the dna.

as soon as the sperm fertilizesthis egg, now, all of a sudden, you havea diploid zygote. let me do that. so now let me picka nice color. so now you're going to have adiploid zygote that's going to have a 2n complement of the dnamaterial or kind of the full complement of what a normalcell in our human body would have. so this is diploid,and it's a zygote, which is just a fancy way ofsaying the fertilized egg.

and it's now readyto essentially turn into an organism. so immediately afterfertilization, this zygote starts experiencing cleavage. it's experiencing mitosis,that's the mechanism, but it doesn't increasea lot in size. so this one right here will thenturn into-- it'll just split up via mitosisinto two like that. and, of course, these are each2n, and then those are going

to split into four like that. and each of these have the sameexact genetic complement as that first zygote, andit keeps splitting. and this mass of cells, we canstart calling it, this right here, this is referredto as the morula. and actually, it comes from theword for mulberry because it looks like a mulberry. so actually, let me just kindof simplify things a little bit because we don'thave to start here.

so we start with a zygote. this is a fertilized egg. it just starts duplicating viamitosis, and you end up with a ball of cells. it's often going to be a powerof two, because these cells, at least in the initial stagesare all duplicating all at once, and then youhave this morula. now, once the morula gets toabout 16 cells or so-- and we're talking aboutfour or five days.

this isn't an exact process--they started differentiating a little bit, where the outercells-- and this kind of turns into a sphere. let me make it a littlebit more sphere like. so it starts differentiatingbetween-- let me make some outer cells. this would be a cross-sectionof it. it's really going to lookmore like a sphere. that's the outer cells and thenyou have your inner cells

on the inside. these outer cells are calledthe trophoblasts. let me do it in adifferent color. let me scroll over. i don't want to go there. and then the inner cells, andthis is kind of the crux of what this video is allabout-- let me scroll down a little bit. the inner cells-- picka suitable color.

the inner cells right there arecalled the embryoblast. and then what's going to happenis some fluid's going to start filling in someof this gap between the embryoblast and the trophoblast,so you're going to start having some fluid thatcomes in there, and so the morula will eventuallylook like this, where the trophoblast, or the outermembrane, is kind of this huge sphere of cells. and this is all happening asthey keep replicating.

mitosis is the mechanism, so nowmy trophoblast is going to look like that, and thenmy embryoblast is going to look like this. sometimes the embryoblast-- sothis is the embryoblast. sometimes it's also called theinner cell mass, so let me write that. and this is what's going toturn into the organism. and so, just so you know acouple of the labels that are involved here, if we're dealingwith a mammalian

organism, and we are mammals,we call this thing that the morula turned into is a zygote,then a morula, then the cells of the morula startedto differentiate into the trophoblast, or kind of theoutside cells, and then the embryoblast. and then youhave this space that forms here, and this is just fluid,and it's called the blastocoel. a very non-intuitive spellingof the coel part of but once this is formed, this iscalled a blastocyst. that's

the entire thing right here. let me scroll downa little bit. this whole thing is called theblastocyst, and this is the case in humans. now, it can be a very confusingtopic, because a lot of times in a lot of books onbiology, you'll say, hey, you go from the morula tothe blastula or the blastosphere stage. let me write those words down.

so sometimes you'll say morula, and you go to blastula. sometimes it's calledthe blastosphere. and i want to make it veryclear that these are essentially the same stagesin development. these are just for-- you know,in a lot of books, they'll start talking about frogs ortadpoles or things like that, and this applies to them. while we're talking aboutmammals, especially the ones

that are closely relatedto us, the stage is the blastocyst stage, and the realdifferentiator is when people talk about just blastulaand blastospheres. there isn't necessarily thisdifferentiation between these outermost cells and theseembryonic, or this embryoblast, or this innercell mass here. but since the focus of thisvideo is humans, and really that's where i wanted to startfrom, because that's what we are and that's what'sinteresting, we're going to

focus on the blastocyst. now, everything i've talkedabout in this video, it was really to get to this point,because what we have here, these little green cells thati drew right here in the blastocysts, this inner cellmass, this is what will turn into the organism. and you say, ok, sal, if that'sthe organism, what's all of these purplecells out here? this trophoblast out there?

that is going to turn into theplacenta, and i'll do a future video where in a human, it'llturn into a placenta. so let me write that down. it'll turn into the placenta. and i'll do a whole future videoabout i guess how babies are born, and i actually learneda ton about that this past year because a babywas born in our house. but the placenta is reallykind of what the embryo develops inside of, and it's theinterface, especially in

humans and in mammals, betweenthe developing fetus and its mother, so it kind of is theexchange mechanism that separates their two systems,but allows the necessary functions to go onbetween them. but that's not the focusof this video. the focus of this video is thefact that these cells, which at this point are-- they'vedifferentiated themselves away from the placenta cells, butthey still haven't decided what they're going to become.

maybe this cell and itsdescendants eventually start becoming part of the nervoussystem, while these cells right here might become muscletissue, while these cells right here might becomethe liver. these cells right here arecalled embryonic stem cells, and probably the first time inthis video you're hearing a term that you might recognize. so if i were to just take one ofthese cells, and actually, just to introduce you to anotherterm, you know, we

have this zygote. as soon as it starts dividing,each of these cells are called a blastomere. and you're probably wondering,sal, why does this word blast keep appearing in this kindof embryology video, these development videos? and that comes from the greekfor spore: blastos. so the organism is beginningto spore out or grow. i won't go into the word originsof it, but that's

where it comes from and that'swhy everything has this blast in it. so these are blastomeres. so when i talk what embryonicstem cells, i'm talking about the individual blastomeresinside of this embryoblast or inside of this innercell mass. these words are actuallyunusually fun to say. so each of these is anembryonic stem cell. let me write this downin a vibrant color.

so each of these right here areembryonic stem cells, and i wanted to get to this. and the reason why these areinteresting, and i think you already know, is that there'sa huge debate around these. one, these have the potentialto turn into anything, that they have this plasticity. that's another word thatyou might hear. let me write that down,too: plasticity. and the word essentially comesfrom, you know, like a plastic

can turn into anything else. when we say that something hasplasticity, we're talking about its potentialto turn into a lot of different things. so the theory is, and there'salready some trials that seem to substantiate this, especiallyin some lower organisms, that, look, if youhave some damage at some point in your body-- let medraw a nerve cell. let me say i have a-- i won'tgo into the actual mechanics

of a nerve cell, but let's saythat we have some damage at some point on a nerve cell rightthere, and because of that, someone is paralyzedor there's some nerve dysfunction. we're dealing with multiplesclerosis or who knows what. the idea is, look, we have thesecell here that could turn into anything, and we'rejust really understanding how it knows what to turn into. it really has to look at itsenvironment and say, hey, what

are the guys around me doing,and maybe that's what helps dictate what it does. but the idea is you take thesethings that could turn to anything and you put them wherethe damage is, you layer them where the damage is, andthen they can turn into the cell that they needto turn into. so in this case, they wouldturn into nerve cells. they would turn to nerve cellsand repair the damage and maybe cure the paralysisfor that individual.

so it's a huge, exciting areaof research, and you could even, in theory, grownew organs. if someone needs a kidneytransplant or a heart transplant, maybe in the future,we could take a colony of these embryonic stem cells. maybe we can put them in sometype of other creature, or who knows what, and we can turn itinto a replacement heart or a replacement kidney. so there's a huge amountof excitement about

what these can do. i mean, they could cure a lot offormerly uncurable diseases or provide hope for alot of patients who might otherwise die. but obviously, there'sa debate here. and the debate all revolvesaround the issue of if you were to go in here and try toextract one of these cells, you're going to killthis embryo. you're going to kill thisdeveloping embryo, and that

developing embryo hadthe potential to become a human being. it's a potential that obviouslyhas to be in the right environment, and it hasto have a willing mother and all of the rest, but it doeshave the potential. and so for those, especially, ithink, in the pro-life camp, who say, hey, anything that hasa potential to be a human being, that is life and itshould not be killed. so people on that side of thecamp, they're against the

destroying of this embryo. i'm not making this video totake either side to that argument, but it's a potentialto turn to a human being. it's a potential, right? so obviously, there's a hugeamount of debate, but now, now you know in this video whatpeople are talking about when they say embryonic stem cells. and obviously, the next questionis, hey, well, why don't they just call them stemcells as opposed to embryonic

stem cells? and that's because in all of ourbodies, you do have what are called somatic stem cells. let me write that down. somatic or adults stem cells. and we all have them. they're in our bone marrow tohelp produce red blood cells, other parts of our body, but theproblem with somatic stem cells is they're not as plastic,which means that they

can't form any type of cellin the human body. there's an area of researchwhere people are actually maybe trying to make them moreplastic, and if they are able to take these somatic stemcells and make them more plastic, it might maybe killthe need to have these embryonic stem cells, althoughmaybe if they do this too good, maybe these will havethe potential to turn into human beings as well,so that could become a debatable issue.

but right now, this isn't anarea of debate because, left to their own devices, a somaticstem cell or an adult stem cell won't turn intoa human being, while an embryonic one, if it isimplanted in a willing mother, then, of course, it will turninto a human being. and i want to make one sidenote here, because i don't want to take any sides on thedebate of-- well, i mean, facts are facts. this does have the potentialto turn into a human being,

but it also has the potentialto save millions of lives. both of those statements arefacts, and then you can decide on your own which side of thatargument you'd like to or what side of that balance youwould like to kind of put your own opinion. but there's one thing i wantto talk about that in the public debate is neverbrought up. so you have this notion of whenyou-- to get an embryonic stem cell line, and when i saya stem cell line, i mean you

take a couple of stem cells, orlet's say you take one stem cell, and then you put it in apetri dish, and then you allow it to just duplicate. so this one turns into two,those two turn to four. then someone could take one ofthese and then put it in their own petri dish. these are a stem cell line. they all came from one uniqueembryonic stem cell or what initially was a blastomere.

so that's what they calla stem cell line. so the debate obviously is whenyou start an embryonic stem cell line, you aredestroying an embryo. but i want to make the pointhere that embryos are being destroyed in other processes,and namely, in-vitro fertilization. and maybe this'll be my nextvideo: fertilization. and this is just the notion thatthey take a set of eggs out of a mother.

it's usually a couple that'shaving trouble having a child, and they take a bunch ofeggs out of the mother. so let's say they takemaybe 10 to 30 eggs out of the mother. they actually perform a surgery,take them out of the ovaries of the mother, and thenthey fertilize them with semen, either it might comefrom the father or a sperm donor, so then all of thesebecomes zygotes once they're fertilized with semen.

so these all become zygotes,and then they allow them to develop, and they usually allowthem to develop to the blastocyst stage. so eventually all of theseturn into blastocysts. they have a blastocoel inthe center, which is this area of fluid. they have, of course, theembryo, the inner cell mass in them, and what they do is theylook at the ones that they deem are healthier or maybethe ones that are at least

just not unhealthy, and they'lltake a couple of these and they'll implant these intothe mother, so all of this is occurring in a petri dish. so maybe these four look good,so they're going to take these four, and they're going toimplant these into a mother, and if all goes well, maybe oneof these will turn into-- will give the couple a child. so this one will develop andmaybe the other ones won't. but if you've seen john & kateplus 8, you know that many

times they implant a lot ofthem in there, just to increase the probability thatyou get at least one child. but every now and then, theyimplant seven or eight, and then you end up witheight kids. and that's why in-vitrofertilization often results in kind of these multiplebirths, or reality television shows on cable. but what do they do with allof these other perfectly-- well, i won't say perfectlyviable, but these are embryos.

they may or may not be perfectlyviable, but you have these embryos that have thepotential, just like this one right here. these all have the potentialto turn into a human being. but most fertility clinics,roughly half of them, they either throw these away,they destroy them, they allow them to die. a lot of these are frozen, butjust the process of freezing them kills them and then bondingthem kills them again,

so most of these, the process ofin-vitro fertilization, for every one child that has thepotential to develop into a full-fledged human being, you'reactually destroying tens of very viable embryos. so at least my take on it isif you're against-- and i generally don't want to take aside on this, but if you are against research that involvesembryonic stem cells because of the destruction of embryos,on that same, i guess, philosophical ground, youshould also be against

in-vitro fertilization becauseboth of these involve the destruction of zygotes. i think-- well, i won't talkmore about this, because i really don't want to take sides,but i want to show that there is kind of an equivalencehere that's completely lost in this debateon whether embryonic stem cells should be used becausethey have a destruction of embryos, because you'redestroying just as many embryos in this-- well, i won'tsay just as many, but

you are destroying embryos. there's hundreds of thousands ofembryos that get destroyed and get frozen and obviouslydestroyed in that process as well through this in-vitrofertilization process. so anyway, now hopefully youhave the tools to kind of engage in the debate around stemcells, and you see that it all comes from what welearned about meiosis. they produce these gametes. the male gamete fertilizesa female gamete.

the zygote happens or getscreated and starts splitting up the morula, and then itkeeps splitting and it differentiates into theblastocyst, and then this is where the stem cells are. so you already know enoughscience to engage in kind of a very heated debate.

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