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Welcome to the lab everyone. Today, we're going to cover five crazy myths about the
human body and we've done myth busting videos in the past but this list of myths continues to grow
and the list actually came from you as we've asked people to post
old wives tales or things they've been told throughout their life that they're not sure
are necessarily true and you delivered and there are some definite doozies out there.
You would not believe some of the things have been told throughout our life
and more importantly, we need to talk about why they're not true because
figuring out what's real versus what's fake will help us with our health and wellness and
making informed decision. So, let's put those myth busting caps on and jump right into this.
Myth number one, period cramps or menstrual cramps stopping when someone gets in the water.
Now, full disclosure, I do not come equipped with female reproductive parts
and I'm not going to pretend that I know what period cramps feel like but I do think we can
go over the accurate anatomy and physiology to help us understand what's going on here.
So, let's take a look at this cadaver dissection. This is a cut through the midline
like so and we're going to take a look at the lower abdomen
and the pelvic anatomy here. Specifically, let's start with the actual uterus here.
So, this is the area that I'm probing on the uterus, this thicker area here is called the
myometrium of the uterus or the smooth muscle of the uterus and that smooth muscle is what's
responsible for the contractions and therefore, the cramping pain during period cramps.
At the same time, the inside lining here where the probe is inside
is called the endometrium and that endometrial lining is being sloughed off and as those
uterine contractions occur, that's going to expel that endometrium and the blood
out through the vaginal canal and that's what's responsible for the menstrual bleeding.
So, go back to this smooth muscle idea just for a second here. Smooth muscle is under
involuntary control, meaning we can't control it on demand, say like we can with skeletal muscle,
we can contract that whenever we want to. So, it's not like someone on their period
jumps into the water and the uterus is like, "Okay, I'll leave you alone for now but as soon
as you get out of the water, be prepared for my wrath." That just doesn't happen. I mean,
could you imagine if it did? I mean, we'd be having period pool parties all of the time.
Period pool parties aside, there may be a couple of reasons why this myth gains some traction.
One of which may be centered around a potential treatment option or a home remedy
and that is the use of say a warm compress or a heating pad
and that may have translated to getting in say like a hot tub or a warm bath.
The problem with that is there's a lot of variability in the amount of relief
someone will feel. Someone may get no relief all the way up to someone
getting some decent relief in everywhere in between. That also does not account for
the different temperatures in different bodies of water say like a swimming pool
versus a lake or a river and as we know, that uterus is under involuntary control and it's
going to continue to contract regardless the temperature of the water you get in.
Another reason why the myth may have gained some traction is sometimes people will report
that they've had less blood flow or at least they felt like they've noticed less blood flow
while in water. Now, there may actually be some truth to that and that's because water
exerts a force or a pressure and when someone fully submerges themselves in water,
there's going to be that pressure exerted on the body and that may slow the external flow
of the blood and the sloughing endometrium outside of the body or getting out of the body.
The uterus will still contract and create that sloughing endometrian in blood but again,
that external flow could be mitigated or slowed by the external pressure of the water but as again,
as we know, the wrath of the uterus from what I've been told will continue to be felt and heard.
Myth number two, shaving making your hair grow back thicker.
The biggest influences on hair growth, thickness, and distribution are genetics and hormones. There
are some other factors like nutritional deficiencies or other diseases or disorders
that can affect the hair but shaving, not so much and let's figure out why.
So, we'll use this skin model and talk about some relevant anatomy here. The portion of the
hair that's outside of the skin is referred to as the hair shaft but the portion of the hair
that's pushed down into the skin and therefore in the follicle is referred to as the hair root.
Now, when we cut our hair or shave the hair, we're mostly getting rid of that hair shaft but
if we are to pluck the hair out, that would actually pull out the hair root as well
and that's associated with pain because there's a nerve ending down here.
Now, when we're talking about this whole idea about hair thickness, let me give you kind of this
different perspective. Let's say we shrank ourselves down to the size where we could
walk on top of the skin and we'll go over to this hair that we plucked out and look down
in the follicle, what we would see if we pluck the hair is this this hollow bag or this hollow shaft.
Some follicles might have a size like so.
Another follicle might be larger in size and you can probably get the idea of comparing those
that if the follicle was larger, the hair would be thicker and that is kind of this
influence on hair thickness again, influenced by genetics and hormones.
If we take a razor across the top and take off the hair shaft,
we're not going to magically increase the diameter of the follicle and therefore,
the hair just from shaving. Some other things that influence like the appearance of
the thickness of the hair is if we were to look at like say a square centimeter
of the skin and we were to count the number of hair follicles in that given square centimeter.
If this area has more hair follicles versus another area that has less
follicles, the one with more follicles is again going to
appear like it's thicker because there's more hair in that given unit of area.
Again, if I were to drag a razor across the skin, I'm not going to magically increase the number of
hair follicles. Just not happening. When we talk about the development of hair follicles,
that actually happens in the 12th week of embryonic development where the epidermis,
this top layer of the skin invaginates inward and we create the follicles. Shaving isn't going to
magically jump us back to this developmental stage and create more of those follicles.
Now, we often will get some push back on this still and that's because when people shave,
a given area of the body, say like the arms or the legs, they'll often say, when the hair
starts to grow back, it just feels more coarse or thicker and we need to look at that from a couple
of different perspectives. One is that your hairs go through certain growth cycles or growth phases.
They'll go through an active growth phase then a regression phase then a resting phase. So,
if we go to those areas, say we're shaving the arms or the legs again,
many of those hairs will be in the active growth phase and if they're in that active growth phase,
they'll be growing close to the same rate even though maybe this hair follicle here
is on day two of its active growth phase but this one's on day 20.
This one on day 20 is just closer to getting to its regression phase than say this one that's on
day two but if I shave them all and now make them all the same length, all of those hairs
that are in the active growth phase are going to kind of have this feeling of that they're
all growing at the same rate now even though they were already in their active growth phase.
Another perspective is, when the hair first starts to erupt, you can see that little nubby
is much less flexible. And the base of the hair coming right out of the skin
actually is a little bit thicker than the tip of the hair and even as the hair grows in length,
it just becomes more flexible and also has that sensation of feeling more soft.
Myth number 3, developing hemorrhoids from sitting on cold cement or cold surfaces.
Well, what is a hemorrhoid? A hemorrhoid is a dilated, stretched, or bulging vein in the
anus. You could kind of think of these as the varicose veins of the anus but
what causes these or what are some of the risk factors for developing an actual hemorrhoid?
Well, one of the common risk factors you'll hear about is pushing or straining too hard
during bowel movements. So, constipation could influence this.
Another risk factor is sitting for prolonged periods of time, especially on the toilet. Now,
this may be where the myth gains some traction, this whole idea of sitting for prolonged periods
of time but this has nothing to do with the temperature of the surface you're sitting on.
Another risk factor is pregnancy. During pregnancy, the pressure inside the pelvic
and abdominal cavities increases but even during labor with the pushing,
that could possibly influence the development of a varicose vain. Another risk factor is just aging.
We all know that as we get older, we get a little more loosey goosey and things are more prone
to stretch so, those veins might be a little bit more risk for stretching as we get older.
So, instead of worrying about the temperature of the surface we're sitting on, we might be better
served thinking about having a high-fiber diet, not straining while we're having bowel movement
and if you're one of those that has to sit a long time at work,
getting up periodically and walking around and definitely avoiding that
trap of sitting on the toilet and playing some game on your phone for about an hour.
Myth number four, a tampon getting stuck inside the abdominal cavity.
Not the vagina but all the way up into the abdominal cavity. No, just no. Let me explain
a couple things here. There actually is a pathway from the vaginal canal into the abdominal cavity.
We're going to see there's some major size issues if we're referring to a tampon case.
Let's say you're an egg or a sperm cell, these tubes and pathways may be just for you. So let's
pretend in this dissection here that you're a happy little sperm cell swimming at your heart's
content up the vaginal canal. You'll eventually make it to the cervix of the uterus, enter into
the body of the uterus and then you could make it into this structure here called the uterine tube.
Now you have to look closely because it's embedded in that tissue there.
But this uterine tube is also known as the fallopian tube. And as we continue up,
it kind of funnels out the end of the uterine tube here and the funnel shape or this end of the
uterine tube is referred to as the infundibulum. If you look closely, kind of teasing out these
little finger-like projections and those are called fimbriae. I going to mention those more
in just a second but I have to say hello to this amazing structure called the ovary here.
So, again, when we're talking about reproduction, let's pretend this fist of mine is the actual
ovary and these my fingers are these finger like injections that are called the fimbriae
and here's the uterine or the fallopian tube, I know, totally looks exactly like
it is in the human body but during ovulation, an egg - if I go back to here, will rupture out
of the actual ovary here and those fimbriae will sweep the egg or attract it and pull it
into the uterine tube, so there is an actual opening in the uterine tube called the ostium
and that egg will move down and again, coming back to this actual section here, inside the uterine
tube here is typically where fertilization takes place or where the egg and the sperm cell unite.
But again, just coming back to this,
you see a major size issue here, tampon is definitely not making it into
the uterine tube, let alone going to have much luck passing through the cervix there.
Now, have I had patients come into the clinic where they've had
a tampon get stuck in the vaginal canal? Yeah and it can happen maybe they forgot and
put a second tampon in and typically what can happen is that initial tampon can get stuck
in these corners or what we call the fornix or the fornices and it's relatively luckily simple
procedure to remove that tampon, not so comfortable but relatively simple.
And so you can kind of think from this idea of getting a tampon pass this point
again, just no, just not happening.
Myth number five, catching a cold from going outside in a cold environment
with wet hair or even going to bed with wet hair. So many of us can relate to this as may
be our parents or grandparents or other family members may have told us that this could happen.
Now in order for us to catch a cold or what we refer to as an upper respiratory tract
infection in the clinic, we have to have a pathogen, most typically a virus,
get inside our bodies and then if it's a virus that virus will get inside the cell,
try to replicate so it can infect other cells.
It's not like these viruses are selective to people with wet hair. It's not like they're
picking us out in the crowd - "Oh this person's got wet - that person's got wet hair - oh this
person went to bed with wet hair, let's just infect them" that's not how it works.
And when we talk about people getting their hair wet in cold environments,
it happens all the time and there's some crazy people, not to point any fingers,
who do it and don't immediately get sick from something like this.
[Screaming]
"Jonathan, Jonathan is going to explain why we do this"
"Oh my gosh!"
"In a YouTube video"
-And to be honest, this is a little bit of a plug for a future video we're going to do
and it's going to be about what cold plunges do to the human body so stay tuned for that. It'll
be a fun one but speaking of future videos, go ahead and go nuts in the comment section below
and let us know some of the myths that you've heard about with the human body and we may use
those in a future myth busting video. If you enjoy using critical thinking
skills and logic like Geoffrey and I do to help us with our myth busting,
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If you're interested in developing these amazing skills, visit brilliant.org/IHA
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20% off their yearly subscription. Thanks for watching and we'll see you in the next video.