The Awkward History of Puberty – Let’s Talk About Hormones | Corporis

January 13, 2020 0 By Jose Scott


Nobody likes talking about puberty for adults it reminds us that our first time getting bullied or our first painful heartbreak and for teenagers currently going through it just Everyday is a living nightmare and you can’t blame them for feeling that way all the familiar Anatomy and physiology is changing so quickly that there’s no anchor to place anywhere It’s one of the most turbulent and interesting times and human development Especially when it comes to hormones, so I wanted to learn more but luckily so have people throughout history in fact ancient scholars had been just Fascinated by this beautifully awkward transition from childhood into physical and sexual maturity for a long Long time ancient societies obviously didn’t know about things like hormones or sperm cells But it was kind of difficult for them to ignore certain aspects of teenagers developments, you know Like the unexplained bleeding or the beards popping up overnight So, you know They had to explain that they use certain biological events to mark the start of a life transition from childhood into adulthood And then made a bunch of completely wrong guesses about what was happening anatomically the ancient Greeks used menarche or a girl’s first period as her marker and then what they thought was a Comparable event in boys what aristotle called the first seed but how would you know when that was old roman, dude? Lucretia’s had an answer semen would start diffusing throughout a boy’s body And then when he reached a mature age, he would have a sexy dream, which would then cause him to discharge? Yep The answer for the first period for girls was the first wet dream for a boy and that’s partly because for a long time Those old school physicians were obsessed with bodily fluids specifically what they called the four humors of the body Phlegm yellow bile black bile and blood if you were sick it was because your humors were out of whack That was their way of explaining most of medicine and Anatomy, right? This is way before the first microscope or cell theory was even a thing like clearly they had no idea what menses were made of This is the blood and other material that comes out during menstruation they thought the body was just trying to lose some excess moisture because again, Everything was humors or according to hypocrite ‘yes semen and menses were just spread throughout the body and they traveled around through the circulatory system But because kids blood vessels were so small Only blood could get through then when they finally got bigger all that stuff could travel down to the genitals and do its thing. Or maybe not. Some people thought that semen could also be a Residue of blood. Humoral theory would be good enough at explaining things that happen on the inside of the body But clearly some things happen to the outside of the body during puberty also like the voice getting deeper or breast development Or muscle growth still everything including the secondary sexual characteristics were attributed to humors At least they were right when they made the observation that girls tended to go through puberty before boys Something that still rings true today and according to the times puberty ended at around 21 to 25 Depending on which society you were asking and what counts is the end of puberty and that’s a tricky definition for any society throughout history partially because puberty takes on such a larger role than just a Physiological change and that might be why when I was researching for this video I found such little information on puberty between the time of Galen and the Renaissance like seriously I couldn’t find anything that actually moved our anatomical understanding of puberty forward over the course of fifteen hundred years But I did find plenty about what it meant Socially to be a child versus an adolescence and that’s something to remember for the next part of this story Puberty isn’t just hormones and anatomical changes It’s also a psychological change and it changes how you’re seen within your family and society and for a lot of cultures It marks the transition from childhood into the adult working life. And of course each culture is different So how they view this transition time into adulthood is going to be different too Now while there wasn’t a big push on our understanding of puberty Specifically there were a few big efforts during the Renaissance and our overall understanding of anatomy We finally started transitioning from that humoral based medicine to the more traditional Western medicine with the modern anatomy that you’re used to today a big shout-out goes to my dude Andreas Vesalius who in 1543 Literally wrote the book on modern anatomy in De Humani Corporis Fabrica or On The Fabric of the Human Body Which you guessed it is where I got the name for this channel prior to Vesalius, Human dissection was pretty taboo So doctors would dissect animals and infer human anatomy from these pig or sheep Cadavers and while a lot of the anatomy crosses over just fine Vesalius corrected a lot of these long-held Misunderstandings like but the big blood vessels actually originate in the heart and not in the liver His book marked a transition from the old school to the new school Anatomy which caused doctors to rethink how certain diseases function including the old humoral theory So with Anatomy rewritten and our invention of the microscope Right around the corner our knowledge of the reproductive system was about to get a huge overhaul But puberty itself would remain a mystery for centuries Remember hormones weren’t discovered until the early 1900s and we didn’t start experimenting on puberty until get this 1948 Literally the same year that Samuel L Jackson was born probably the most influential work came from James M Tanner a British pediatrician whose book growth at adolescence was super important in our understanding Of puberty Tanner was planning on studying the effects of malnutrition in children And as part of his study He would periodically measure and photograph a bunch of tweens going through puberty and he measured everything height and weight, of course But also stuff like genital size and pubic hair and muscular growth Which I know sounds kind of messed up and ethically questionable but Tanner was really interested in the growth spurt that happens during puberty He still measured all the private stuff because he liked the Greeks thousands of years before him knew it was all supposed to develop during Adolescence he had to make sense of this growth spurt with the as he put it spectacular development of the reproductive system which takes place at this time Tanner called this the adolescent growth spurt and described it his growth of Everything including the face heart pelvis everything. It wasn’t just a stretching out in height and Tanner collected a ton of data he was able to take the timing of a child’s growth spurt their current height where they were at in physical maturity and make really Accurate predictions about their end maturity Tanner had so much data and observational power to work with that He came up with a scale for physical and sexual maturity in puberty that he called the Tanner stages a scale that pediatricians still used today Tanner stages let doctors use an individual child’s Anatomy to determine where they’re at in puberty that way it wasn’t just Oh, you’re 13 and you don’t have a beard yet? You could have just been a late bloomer and only been at stages one or two on the Tanner scale and that’s all fine But that really just doubles down on the idea that puberty is the time when people reach sexual maturity. It doesn’t offer any explanation Physiologically and it doesn’t bring hormones into the picture at all And while he wasn’t a hundred percent accurate for everything Tanner did correctly credit puberty to a cascade of hormonal changes Not just a single hormone. Again. This is bonkers considering the technology available to him Remember all of this is during the 1950’s so important medical tools like the radio immunoassay hadn’t been invented yet Tanner was measuring all this stuff off of metabolic byproducts He was finding enduring low-tech stuff by today’s standards Plus while key hormones like growth hormone had been discovered some of the big chemicals involved in puberty like Hypothalamic peptides or insulin like growth factors or IGFs hadn’t been discovered yet. What Tanner did know was that the Hypothalamus the gland that sits just above the pituitary gland in the brain Needs to mature before the pituitary so that the cascade of hormones can happen So researchers started diving into the Cascade if you saw the last episode in the hormone series Then you might remember that the pituitary gland controls just about every other endocrine gland in the body Including the gonads the testes and ovaries, but the hypothalamus controls the pituitary so back in 1980 a team of researchers did a series of experiments on rhesus monkeys a monkey that gets Experimented a lot on in science. They showed that if the hypothalamus released pulses of ganado trope and releasing hormone or GnRH It would kick off a chain of events that triggered the release of adult levels of ganado tropen from the pituitary Which would stimulate adult level responses from the gonads real quick language sidebar here? I know I just threw in a bunch of big science words But breaking them down makes them simpler the go natto part just refers to the gonads the testes and ovaries Well the trope in part just means that it triggers the release of other hormones So good nod at rope ins job is to release hormones from the gonad so GnRH s job is just to release gennady tropen and all of that is to say is that researchers found that the hormonal response of the testes and ovaries Starts in the brain and that’s all well and good in monkeys But good luck getting approval doing an experiment that literally triggers purity in human children Well at least in healthy human children It might be a little bit of a different story if we were experimenting on someone with a disease Which is exactly what we got around the same time research was looking at a condition called calman syndrome a condition where GnRH doesn’t work properly in the Hypothalamus the child never really starts puberty and sure enough by stimulating the release of GnRH like they had done with monkeys People with calleman’s syndrome were induced into puberty and that seemed like the nail in the coffin right there Kanata trope and releasing hormone acted like a puberty on switch but like all things hormones You don’t just sprinkle on a little gnrh, and that’s puberty. Nope. It’s all feedback Loops and puberty is controlled by something called the hypothalamic pituitary. Gonadal axis these two are in the brain while this one is not although I know plenty of dudes who think more when they’re GnRH is released from the hypothalamus and as it keeps rising for sure Gennady tropen will increase but so will hormones like Luteinizing hormone which kicks off ovulation and the development of the corpus luteum as well as follicle stimulating hormone Which regulates? Development growth and some reproductive processes in the body like making sperm and egg cells Then the testes and ovaries talk back to the HP part of the HPG axis with androgens progesterone x’ and esther owns so at the end of puberty The biggest change is that now you’re a teenager with the anatomical frame of an adults and you can have a baby But don’t bad for the environment. You’re also set up with different levels of hormones than before including the all-important and fascinating estrogen and testosterone But there’s another hormone that doesn’t get enough credit after puberty Supposedly known as the love or trust hormone oxytocin and that’s the subject of next week’s episode Thank you so much for watching this episode. If you somehow stuck around would you mind sharing this video with a friend? I really appreciate it. Otherwise say hi in the comments subscribe if you haven’t already like the video have fun be good