What is the deal with anuses?
Is it true that, at one point in our development, we were all nothing more than an anus?
What exactly is it even for?
What is it made of?
And how is this all connected to an unexploded WWI artillery shell?
Well, hold onto your butts because we’re about to answer all of those burning questions
– and more!
Hey, you in the back! Stop giggling, this is a serious scientific video!
The word ‘anus’ is actually derived from Latin and translates to ‘ring’ or ‘circle’
in English.
We’ve all got one, and – let’s be honest here – we all know what they’re for.
The anus, for humans and most animals alike, plays a vital role in our digestive systems,
as well as…
well, let’s just say ‘what comes after’ for now.
Despite everyone on the planet owning one, talking about the anus and its functions can
often be considered something of a taboo and even disgusting topic to some.
That can lead to some of us even feeling shame or disgust at ourselves if we develop certain
disorders or conditions that affect the anus, which in turn can cause it to become a difficult
topic to broach when seeking medical assistance for those problems.
Just like developing our understanding of any other part of our bodies, getting to grips
with the anus can allow us to better appreciate its significance and eliminate any misconceptions
we might have.
As somebody who owns an anus, you might already know the primary bodily function of the anus
is to regulate the exit of feces from the body.
In order to do this, an anus is located at the end of the rectum.
Hold on a moment, aren’t those the same thing?
Well, while you might have heard them used interchangeably – as either insults or for
some high-brow jokes – the anus and rectum are actually two distinct parts of the digestive
system.
Speaking of which, let’s take a look at that whole process, to get an idea of exactly
how the anus functions as part of this important bodily function.
You see, as you may already be aware, your digestive system has both a small and a large
intestine; those are the two large tubes that perform a process known as peristalsis.
This is the name given to the movement of the inner walls of these hollow internal organs.
Both the small and large intestines contain a layer of muscle in order to move food and
liquid through your gastrointestinal tract.
As the muscle behind all the food you consume contracts, it squeezes all that food forward
while the portion of the muscle in front relaxes, allowing everything you’ve eaten and drank
to pass through it.
Once you have eaten or drank something, you might not give much thought to where it goes
once it’s no longer in your mouth.
But from there, it travels down your esophagus, which also performs this process of peristalsis.
The reason you have never noticed it is because it's completely automatic!
Your brain sends electrical signals through your body to the relevant parts involved in
specific biological and physiological processes, meaning it all takes place without you ever
having to think about it.
That is also how food passes from your esophagus through your lower esophageal sphincter, a
ring of muscle that is essentially the door to your stomach, designed to let what you
eat in while also preventing your potentially harmful stomach acid out.
Your stomach, as you probably know, is responsible for mixing your eaten food acids that break
it down as part of the digestive process.
These resultant contents are known as chyme, and that is what then gets passed through
your small intestine.
There, the muscles of your small intestine add further digestive juices from certain
other organs like your pancreas and liver.
They will also extract and absorb water and nutrients from your food, then add those to
your bloodstream.
Next, the leftover waste products are moved onto your large intestine as the process of
peristalsis continues.
Any of the waste going through the large intestine – normally consisting of undigested food,
excess fluid, and even your own old cells from the lining of your gastrointestinal tract
– changes into…
well, the end result.
That waste continues from your intestines to your colon, which is made of much the same
stuff, namely, layers of muscle and tissue, with glands that can absorb and secrete different
substances.
After going through the length of the colon, food waste then heads to the rectum – and
now you are going to find out the difference!
You see, the rectum is located at the lower end of your large intestines, which are long,
continuous tubes that also include your colon and the anus.
The rectum is where food that has been reduced to solid waste is stored.
Once it arrives, the rectum stores the waste and absorbs any remaining water until the
time comes to release it.
Think of it as the last stop, right at the end of the line, before the train then leaves
and heads off towards its shed.
It’s a journey that starts when your food enters your mouth and terminates when it gets
to the last six inches or so of your large intestine.
Once it arrives there, it just has to wait for one last signal before it’s able to
make its final departure.
Your rectum is connected to an anal canal, where your food makes its eventual exit from
your body.
As the remaining waste passes from your colon and then into your rectum, it collects there
until your nerve endings trigger your urge to… well, there are no nice ways to say
this, but your urge to poop.
When that waste matter moves into the rectum, nerve receptors located there will send signals
to the brain, alerting you if you need to evacuate that waste or if it’s just gas.
If it’s the latter, then you’re brain knows it’s safe for you to expel it without
issue – well, it’s not always a basket of roses for whoever happens to be sitting
next to you.
If it’s time to get rid of waste, those same nerves will let you know to get moving
to the nearest bathroom!
Similarly, the anus has a high concentration of nerve endings, making it a highly sensitive
area of the body.
This sensitivity can vary from person to person, but typically the anal canal continues on
from your rectum, making up the last few centimeters of the large intestine.
The anus consists of a ring of muscle and actually has several other important muscles
that aid its function.
The anal canal is surrounded by these ring-like muscles that are called sphincters that are
designed to control your bowel movements.
Both of these – the external and internal sphincters – are located at the anus.
The external one is voluntary, meaning it can be contracted or relaxed at will, while
the internal sphincter does so involuntarily.
The canal is also lined with a mucus membrane, a thin layer of moist tissue containing glands
that produce mucus – a slippery fluid that can help that waste make its dramatic exit.
From there, well… you don’t need us to tell you what happens.
Let’s instead talk about some other things you might not know about the anus!
The anus is actually a part of your body’s most powerful group of muscles, along with
the gluteus maximus, the gluteus medius, and the gluteus minimus.
Much like other muscles in the body, the anus possesses a degree of elasticity, meaning
it can stretch and then return to its original state.
This allows our muscles to carry out their specific function, and the anus is no exception.
That also means that – again, just like other muscles - the more you exercise it,
the stronger it can get.
Pilates is actually a great way to strengthen your pelvic floor muscles, which the anus
is connected to!
Now, as we mentioned before, largely given the role it plays in our digestion, the anus
is socially considered to be a taboo part of the body.
As a result, you might often hear some people refer to it using it using slang terminology.
There are well over fifty different colloquial terms for the anus, many of which are considered
to be so vulgar that they’re actually considered curse words, which means that we can’t cite
a lot of them as examples for this video (we’re already on thin ice as it is right now!)
Some of the slightly more esoteric ones are phrases like ‘ring piece,’ and ‘starfish’.
We’ll stop with those two before we get ourselves demonetized!
Depending on the context, some of these slang terms can be considered positive, negative,
or even downright nasty and vitriolic.
While to some, it’s often considered to be something of a funny body part, hence the
use of profane slang to refer to it, it’s also an incredibly important part of our anatomy
and shouldn’t be joked about in a scientific context.
Speaking of how important the anus is, did you know that without one, you could possibly
die?
If not, you would certainly live in a lot of discomfort.
You might have heard that the anus is normally one of the first parts of the body to develop
when humans begin as embryos in the womb, meaning that at some point, everyone was an
asshole!
Joking aside, that is not strictly true.
Humans are similar to an evolutionary branch of animals known as deuterostomes.
The defining characteristic of deuterostomes is that their anus does form before their
mouth while they are an embryo.
This can be found in a number of creatures in the animal kingdom, including any vertebrates
– animals with a spinal column – and, in particular, starfish, sea urchins, and
sea cucumbers.
In the case of sea cucumbers, their anus isn’t just an exit for digestive waste; it’s also
a mouth that it uses for eating algae, a defensive weapon that can launch a stringy web of internal
organs at underwater predators, and its main way of breathing.
Sea cucumbers are considered to just be a multi-function Swiss army knife-style anus
that just happens to have a body around it.
On the other hand, human beings, evolved in such a way that we no longer follow the same
pattern of deuterostomes.
In human embryos, the mouth forms first during the fourth week of development.
Four weeks later, this is then followed by the anus, and the two are connected by a gut
tube that would have already formed between them.
However, sometimes human babies can, in fact, be born without an anus as a result of a birth
defect known as an imperforate anus.
This affects one in around every five thousand newborn babies and can occur alongside other
abnormalities that affect the rectum and anus.
While we don’t exactly know what causes an imperforate anus, it can manifest in a
number of alarming ways.
Some imperforate anuses result in a complete absence of an anal opening, while others cause
the formation of an anus but in the wrong place on the body, usually a lot smaller than
it needs to be.
In some instances, something called a cloaca develops, which is when the anus, urethra,
and other openings are all combined into a singular one.
Naturally, this can lead to a whole host of problems for a newborn, with the most worrying
one being that, without an anus, an infant can’t expel their waste, which – if you
or anyone you know has kids, you’ll know – happens a lot.
This, alongside possible infections as a result of the birth defect, can lead to early health
complications and even death if the newborn isn’t treated ASAP.
This is a good time to mention the waste-expelling process and how we learn about it.
During our earliest stages of life, our brains haven’t learned how to properly control
our digestive and excretory systems yet.
For older children and adults, this is like second nature.
We know when our bodies are telling us we need to go, and we can even control the muscles
of the anus to stop ourselves if we aren’t able to get to a bathroom quickly.
For infants and even some adults who develop certain neurological or muscular disorders
as they grow older, that level of control just isn’t possible.
This is a big problem for someone born with an imperforate anus, as their large intestine
doesn’t end with an opening; it essentially becomes just a pouch.
This can cause the waste to collect internally within the large intestine.
If it stays there, it can cause vomiting or even make the abdomen swell up.
The only way to treat an imperforate anus is with urgent surgery, which will create
a new opening for waste to pass through.
While this surgery can differ, it typically involves three stages.
The first is a procedure called a colostomy, where a stoma needs to be created.
This is an external opening that brings the intestine out from under the skin.
Waste is passed through the stoma into a bag that has to be worn outside the body.
Yes, we know how unpleasant that sounds, but try to remember: it has to be even more uncomfortable
for those unfortunate enough to have to live with one.
The second part of the surgical process is called an anoplasty.
This involves creating a new opening, a new anus in the usual place, and pulling the rectum
down to meet it.
If someone with an imperforate anus also has a fistula – a connection between the intestine
and bladder or urethra – then that also needs to be closed off.
Then, after several months, once the new anus has healed, a third procedure is performed
to close the stoma.
While this is normally done while the person is still a baby in order for their body to
adjust and for the digestive system to begin functioning properly as soon as possible,
that doesn’t always happen.
One man in China had to go a whole fifty-five years without an anus in the proper place!
A farmer from Hubei Province named Wu was unable to afford the necessary operation until
he reached his later years, which means that for half a century, he had to… ‘make do’
with a small surgical hole around half a centimeter in diameter.
He only had a stoma, part of the colostomy that makes up the initial surgical fix for
an imperforate anus.
Wu also had to squeeze waste out by hand, which of course, sounds like a horrific and
messy way to use the bathroom.
He had to pay close attention to exactly what foods he ate in order to avoid constipation
and use laxatives to evacuate his bowels thoroughly.
In something of a happy ending, though, not only did his condition not prevent Wu from
getting married and having children, but he did also undergo surgery to fix the defect
after five decades without proper treatment.
As the anus is an orifice that leads directly into your body, naturally, it makes it a site
for potential infection.
There are a number of diseases that can potentially affect this part of your body, including anal
cancer, anal fissures (which is when the lining of the anus tears), anal warts or abscesses,
sexually transmitted infections, and hemorrhoids – dilated, twisted blood vessels in the
wall of the anus or rectum.
Given just how easy it can be to develop illnesses and infections like these, it's important
to practice good hygiene when it comes to the anus.
Cleaning it should be done with care, either by wiping the exterior or rinsing it with
water.
Occasionally, some people decide to remove the naturally occurring hair that develops
around the anus during puberty.
Brazilian waxing, trimming, or even shaving are all ways to do this, as well as bleaching
that can lighten the darker look of the anus.
Speaking of showing your anus some appreciation, it often has an essential role in sexuality.
For many consenting adults of varying gender identities and sexual orientations, sexual
activity that involves stimulating the anus is considered an enjoyable experience.
For some, the anus is actually an erogenous zone – the areas of the body most affected
by enjoyable sensations.
Not everyone’s erogenous zones are the same, but the anus is among one of the most common.
But be careful what you do down there because, according to a study conducted by some scientists
in New York, a staggering four thousand Americans are taken to hospital each year with objects
lodged up their anus and stuck in their rectum.
This isn’t exclusively related to sexuality either, with objects ranging from marbles
and bottles to stationary – and even drugs!
Further examples include a shampoo bottle, chicken bones, an oven mitt, a light bulb,
and a water balloon.
The analysis these scientists carried out revealed that almost forty thousand people
were admitted to hospital emergency departments for injuries like this between the years 2012
and 2021.
In eight out of ten cases, the patients were men, with those in their twenties and early
thirties making up a third of all these visits to the emergency room.
But we know you want to hear about the craziest story like this.
Well, in 2022, an elderly man was admitted to hospital…
with an undetonated World War One bomb lodged up his anus and in his rectum.
No, really – we’re not making this up!
The man was 88 at the time when he was admitted to the Hospital Sainte Musse in Toulon, southern
France, with an eight-inch artillery shell that had found an unlikely target.
It even triggered a bomb scare at the hospital, but luckily, bomb disposal experts were able
to determine that the shell was unlikely to explode while it was still lodged inside the
man.
Fortunately for him, the doctors were able to remove the bomb from its confinement without
any explosive incident occurring.
After all, we’ve said thus far you might think that the anus is an inherently dirty
or germ-ridden part of the body, but it’s very much worth remembering that, as long
as you maintain a good standard of hygiene, then that simply won’t be the case.
In fact, it’s worth remembering that there are actually more germs and bacteria present
in your mouth than in your anus.
No, really!
It’s actually a misconception that the types of harmful bacteria that can cause diseases
are found in supposedly ‘dirtier’ places on the body.
For one, not all bacteria feed on waste matter, but for another, thanks to all the food that
we intake, which could be carrying innocuous bacteria and airborne bacteria breathed in
through the mouth, we actually do have more bacteria in our mouths than anuses.
Before you panic, that’s not always a bad thing either!
Oral bacteria also perform a lot of important functions, and most of the bacteria that enter
your gut and reach the anus, harmful or otherwise, only get there because they enter through
the mouth.
Now watch “Weird Facts About Testicles.”
Or check out “Weird Facts about the Male Body”