Today's video is sponsored by Keeps.
Find the link in the description below.
When I was a little kid, I used to have this fear that my bladder would explode if I helped
my pee in for too long and I remember that my big sisters one day decided to exploit
this and lock me out of the house when I desperately needed to pee.
So, there I was pounding on the door super viciously, screaming at them to be let in
but of course, they didn't because they're big sisters but luckily for me, my bladder
did not explode.
Instead, I aggressively peed my pants on the front porch, but it begs the question, has
I just been an irrational seven year old or is it actually possible for your bladder to
rupture?
In today's video, we're going to use the cadavers to take a look at the urinary system to answer
that very question.
So, if you haven't used the restroom lately, now might be a good time to do so.
Let's do this...
[Intro]
Let's start off by taking a look at the urinary system and discussing some of the basic functions
of the organs and structures inside of it.
So here, we have a kidney that's been cut in the frontal or coronal plane, meaning that
it's just been divided into front and back portions.
Now, the kidney's job is to filter your blood as well as adjust hydration levels.
So, this outer rim of the kidney that I'm tracing with the probe here is called the
renal cortex and this is going to be filled to the brim with tiny little filtration units
that will filter the blood and drop waste into these darkened portions here called renal
pyramid.
These renal pyramids will then transport the waste with water, which we now call urine
into the actual urinary tract which is going to begin in this area here and then, it's
going to transport that urine down this really long tube called the ureter.
Now, this is going to transport that urine to the urinary bladder and we can see a urinary
bladder right here.
That's what this is right here.
So you're looking at a cross section of a female pelvis.
We can see the pubic bone, you can see the vaginal canal right there, you can see the
uterus but this structure here is going to be the urinary bladder that has been cut in
the mid sagittal plane.
Now, the bladder is going to be a storage organ for urine, obviously, and it can store
at maximum around one liter of urine but that's at maximum.
Normally, most people around 4 to 500 milliliters, which is around two so cups of urine.
At that level that's when you're like you know, maybe I should probably go ahead and
urinate.
But do remember that one litre maximum capacity because that'll be important later.
But it's also important to understand that the urinary bladder is a convenience organ.
Meaning you don't actually need to have a urinary bladder and some, more of many creatures
on this planet don't.
They simply produce urine and then the urine leaves their body.
But the reason why most people think we have a urinary bladder is to help mark our territory.
So, we can pee on things and say, "Hey, this is mine" or "this is my space" or "I've been
here" or "This is a warning, you're entering my territory" so you'll save up all this urine
and then, you can expel it as you choose but you can also do it at the right time and that's
going to be important also coming up later.
But the bladder will then have another extension coming off of it called the urethra.
Now, we can't see that in this cross section but you can kind of picture that there would
be this short muscular tube coming off of the bladder.
Now, how short depends on whether you're a male or a female.
Females are obviously going to have shorter urethra than a male would but this is simply
going to evacuate or empty the bladder.
So, it's going to take that urine and it's going to leave the body.
Speaking of leaving the body, you may have noticed that the hair on the top of my head
is leaving my body.
Look, I was in denial about my hair loss for years.
I can't tell you how many times I would defend myself when my friends would make jokes about
my receding hairline by saying that no, I just have a really high forehead but eventually,
you see enough pictures of yourself that you can't really do that anymore and you just
have to start accepting the fact that you are losing your hair but here's the thing,
it doesn't have to be that way all of the time for everyone and that's why I'm excited
about the sponsor of today's video, Keeps.
Keeps is a subscription service devoted to helping men keep their hair.
They do this through clinically proven treatments with most customers seeing results around
six months or so after starting treatment.
These treatment plans are affordable and they're delivered straight to your door.
The fact is, two out of three men will experience hair loss by the time they're 35 years old
which is why if you're starting to see those early signs of hair loss, now is the best
time to jump on this and take advantage of these doctor-recommended treatment plans without
ever having to visit a doctor's office or a pharmacy.
Plus, you'll even get refill reminders so you'll never run out of the products you need
to take care of your hair.
Hair loss stops with Keeps.
To get 50% off your first order, visit keeps.com/anatomy or you just click the link in the description
below.
That's K-E-E-P-S.com/anatomy.
Alright, let's get back to it.
Let's start by discussing what's called the Micturition Reflex.
Now, that's a big word but Micturition just means the desire to urinate.
So, if we go back to this mid sagittal section of the pelvis.
Again, this right here is that urinary bladder.
The inside lining of the bladder itself as well as other aspects of the urinary tract,
there is a specialized type of epithelium called transitional epithelium and the reason
it's called transitional is because depending on how much urine is inside of the bladder
and urinary tract, it will stretch and transition to different thicknesses.
So, less urine, it's thicker.
More urine, it's more flat and stretched out.
Thus, transitional epithelium.
Next, we have the muscle of the bladder itself.
This is called detrusor muscle.
That's its name but it's really just a type of smooth muscle.
Now, smooth muscle is involuntary.
Meaning, you are not in charge of when this muscle here contracts.
Instead, that is going to be reflexive.
Now, we can't see the urethra coming off of here but the urethra is going to have two
sphincters which are just really thick and tight muscular rings.
The first sphincter is called the internal urethral sphincter and again, this is involuntary.
You're not in charge of contracting or relaxing this sphincter.
We'll see why that's important in a moment but you are in charge of the more distal sphincter
called the external urethral sphincter.
This one is made of skeletal muscle which means you can decide when it contracts and
when it relaxes but what you need to understand is that inside of this detruser muscle, there
are stretch receptor neuron and what they're doing is they are monitoring how much urine
is filling inside of the bladder and what they're going to do is send that signal so
they're going to send their signal up the spinal cord and that spinal cord will then
send a motor neuron back or a signal back to the detruser muscle telling it to contract.
That's right.
S
o, once you reach about around like, I think it's 200 milliliters or so of urine, what's
going to happen is those stretch receptors will send a neuron and they'll get another
neuron and signal back saying "contract" and that's also going to tell that internal urethral
sphincter to relax.
So, this is that initial urge to pee.
Alright?
When you're like, "oh I got - I gotta pee here".
What's happening is the bladder is actually contracting and the first sphincter is opening
letting urine down but you are in charge of that external urethral sphincter and that's
because at the exact same time, signals are going up the spinal cord, they're going to
this region of the brain stem here called the ponds.
Inside of the ponds, there's something called the pontein micturition center and the signals
going to go to that PMC as well as go to higher areas of the brain specifically this medial
prefrontal cortex in this area here and what's going to happen is you are able to decide,
"Hey, this is not a good time to urinate".
I mean, think about it.
Imagine you're in like a, you're in a social, right?
You're among friends - if you didn't have control of that external erythral sphincter,
well your body would just start urinating on your own and you just be peeing your pants.
So, the decision to keep it contracted comes from the cerebral cortex up here, right?
You can actually make the decision.
What you have to understand though is the PMC and the cerebral cortex are working together
to kind of not only figure out how or when we should be peeing but how to actually do
it because when you decide to pee, then the signal's going to go back down that same pathway
and it's going to be reflexive again.
It's going to cause this detruser muscle to contract.
That internal urethral sphincter to open and now the external urethral sphincter will also
open and this creates a pressure gradient and the urine is going to then be released.
So, knowing all this, is it possible for the bladder to rupture or explode?
And the short answer is, yes.
The long answer is, it's very unlikely to happen simply from you holding your urine
unless you had something else already wrong with the bladder.
So, let's look at this.
If the bladder ruptures, there are two different types of bladder ruptures.
If it ruptures into this space here, into the pelvic cavity, this is called the peritoneal
space.
If it ruptures, say on the top of the bladder here, it goes in here.
We call that an intraperitoneal rupture.
In this event, the urine will be reabsorbed by the body which will then kind of cause
havoc and chaos with your bloodstream 'cuz it's - the urine is literally reabsorbed into
it but it's also going to require surgery to close off that rupture, but if it ruptures
at another point, let's say deeper down in this tissue here, we call that an extraperitoneal
rupture and this is actually easier to manage because you can just administer a catheter
and drain out the urine from that space but you may be asking, "Well, how does happen
though", right?
If I'm saying that there needed to be something else wrong with the bladder, well, most cases
of bladder ruptures happen due to this bone here.
This is the pubic bone and if this breaks due to some kind of trauma, that can cause
ruptures to the bladder and the most common cause of those ruptures are going to be automobile
accidents.
Picture the steering wheel hitting your pelvis, hitting the pubic bone and then it ruptures
some aspect of the bladder.
But other things that can happen are like bladder cancer, right?
If you have bladder cancer, that can weaken the wall of the bladder and then it makes
it more likely for a bladder rupture to occur.
Uh, vaginal birth.
Simply putting the child through there, there have been instances where that has actually
caused a bladder rupture to occur.
Maybe someone is administering a catheter to you, right?
They're going to drain the bladder and they don't do it correctly and they cause an injury.
Those are all pre existing conditions or some kind of trauma event that is weakening the
bladder which is causing that to occur - the bladder rupture to occur.
Simply you holding your urine, it's really not all that likely.
I mean, I looked - in preparation for this video, I was looking in the published literature
looking for case studies of spontaneous bladder ruptures and finding them without some kind
of pre-existing condition, I couldn't find any that were really reliable if - it was
more just mysterious.
As in, we saw happen, we saw this individual, this happened to them but when you trace back
their history, it does seem like they had some kind of inciting event.
Something else happened to their bladder at some other point.
The reason why this is so unlikely is because as that bladder is reaching that maximum capacity
of one liter, it makes far more sense for the urine to go up the ureters, to go head
towards the kidney and that can and does happen.
That can create urinary tract infections, kidney infections, you can send you into kidney
failure, you can actually die from urine going back up the kidneys, but a far more likely
result, instead of your bladder just rupturing is exactly what happened to seven-year-old
Justin when your external urethral sphincter just opens and you aggressively pee your pants.
See, that makes more sense from a body's perspective, right?
Like, would you rather have the bladder rupture and urine go into this body cavity or into
the tissues or would you just rather pee your pants and suffer a little bit of humiliation?
Again, both are not ideal but I'm pretty sure I know which one I would choose.
Thanks again to the sponsor of today's video, Keeps.
Be sure to click the link in the description below or just visit Keeps.com/anatomy and
get 50% off your first order today.
As always, be sure to Like, comment, subscribe if you feel so inclined.
We really do appreciate those subscriptions.
They really do help our channel perform better so we can get in front of more people so we
can teach them about their bodies.
So, it is very much appreciated if you feel so inclined but thanks again for watching
and I will see you in the next video.