- 4 weeks ago
Discover the magic within your body as we take you on a captivating journey through the fascinating world of your muscles and explore the extraordinary potential of some lesser-known body parts.
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00:00Your muscle system is like a complicated mechanism where every part has its essential role.
00:05When one part breaks, wait, did you just yawn?
00:09I hope that was not a reaction to my storytelling.
00:12But I can tell you this, even something as basic as a yawn is a result of a joint effort
00:17of several muscles in the chest,
00:19diaphragm, larynx in the throat, and palate in the mouth.
00:23Muscles are soft tissues made up of many stretchy fibers.
00:26You have over 600 of them in your body, and they help you move, maintain posture, breathe, digest food, thread
00:34a needle, take selfies with your phone, and many other things.
00:38Time to have some coffee, and now that you're reaching for your cup, you're engaging several groups of muscles.
00:43Let's see how it works on the inside.
00:46First of all, we have the muscles in your arm, like the biceps.
00:50The elbow needs to bend, and the biceps help with that.
00:53And there are also some backup helpers.
00:55In your case, the triceps on the opposite side of the arm.
00:59They relax and lengthen to make the bending happen, just like this.
01:03To keep the movement smooth and controlled, you need to engage the stabilizer muscles.
01:08The rotator cuff in your shoulder can help with that.
01:10It will keep your joint steady and won't let it wobble as you're reaching for the cup.
01:15And that's still not all.
01:17The muscles in your forearm help the biceps in flexing the wrist, making sure your hand reaches the cup just
01:23right.
01:23You can finally enjoy your drink now.
01:26There are three types of muscles in your body.
01:29Skeletal, smooth, and cardiac.
01:32Skeletal muscles are attached to your bones by tendons.
01:35Those are cords made of tough tissue.
01:37Skeletal muscles are responsible for voluntary movements.
01:40They're the only type of muscles you can control to set specific areas of your body in motion.
01:44For example, when you contract a skeletal muscle, you can move your limbs or run and lift weights.
01:49This type of muscle makes up 40 to 50% of your total body weight.
01:54Smooth muscles populate various organs and systems throughout your body.
01:58They line the walls of organs in the digestive system, respiratory system, cardiovascular system, reproductive system, and more.
02:06They have a smooth, non-striped appearance, hence the name smooth muscle.
02:10You cannot consciously control their movements.
02:12Each smooth muscle cell is rounded at the center and tapered at the sides.
02:17They are connected to other neighboring cells, and they form a mesh-like network that allows them to contract in
02:23symphony.
02:24Thanks to this coordinated movement, some important processes in your body work smoothly.
02:29I'm talking about processes like digestion, breathing, and blood circulation.
02:33So it's a big deal.
02:36Cardiac muscles are pretty picky when it comes to accommodation.
02:39They only reside in the heart, and there's just one cardiac muscle per human.
02:43Its other name is the myocardium.
02:46The cardiac muscle looks a lot like the skeletal muscles.
02:49It has long, thin, parallel streaks.
02:51But unlike skeletal muscles, this guy is uncontrollable.
02:55I mean, it works all the time without you making any effort.
02:58The thick muscles of the heart contract to pump the vital fluid out, and then relax to let it back
03:03in after it has run through the body.
03:06If your muscles were to compete in the Muscle Olympics, you'd see some champions among them.
03:11The title of the largest muscle belongs to the gluteus maximus.
03:14It's the main extensor muscle of the hip.
03:17Its job is to support your trunk and keep your posture under control.
03:20Thanks to it, you can walk upstairs.
03:23The smallest muscle in your body is cozily located in your inner ear.
03:27It connects to your eardrum and stabilizes the smallest bone in the body, which is also here, inside your ear.
03:34The medal for being the strongest muscle goes to the masseter.
03:38This little guy is the muscle in your jaw.
03:40But don't let the size trick you.
03:42It can close your teeth with a force of 200 pounds on your molars.
03:47The biggest workaholic among your muscles is the heart.
03:50And yes, your heart is a muscle and an organ at the same time.
03:54A muscular organ, that is.
03:56It pumps about 2,500 gallons of blood per day.
04:01The tongue is another hard worker in your system.
04:04It's made up of muscle groups and never takes a day or even a minute off, just like the heart.
04:08It helps you mix up food and speak, it filters out germs, and even when you're sleeping, it keeps pushing
04:13saliva down the throat.
04:15Nearly 85% of all the heat generated in your body is a result of your muscles contracting.
04:21When you feel cold, your muscles automatically contract.
04:24That's why you start shivering.
04:26It's your body's way of using muscles to generate heat and warm you up.
04:30Your muscles work together, performing different movements.
04:34They do it in pairs.
04:36When one shortens, its partner lengthens.
04:38It's like when you're doing bicep curls.
04:40When you curl your arm up so the bicep gets shorter, the tricep on the other side of your arm
04:45straightens out.
04:46When you bend your arm at the elbow, you're performing flexion.
04:50It's the movement that decreases the angle between two body parts.
04:54Extension is the opposite of flexion.
04:56It increases the angle between two body parts, like when you're straightening your arm after bending it.
05:03Abduction is when you move a body part away from the midline of your body.
05:07Raise your arm out to the side.
05:09That's abduction.
05:10When you turn your head from side to side, you're doing a rotation.
05:14Contraction is the shortening and tightening of a muscle.
05:16When a muscle contracts, it pulls on the bones it's attached to, resulting in movement.
05:21When you bend your knee, the muscles in your thigh contract to bring your lower leg closer to your thigh.
05:26And now my personal favorite, relaxation.
05:28A muscle returns to its resting state after contracting.
05:32It seems like they're capable of anything, but muscles can't push.
05:36So even when the door says push, and you're pretty sure you're doing it,
05:40your muscles are pulling your elbow and shoulder against the door.
05:43Muscles have the superpower of viscoelasticity.
05:47It means they act like a combination of a fluid and an elastic material when they are stretched or compressed.
05:53When you push or pull on a muscle, it can resist the change in shape like a thick liquid, viscous,
05:58or bounce back to its original shape like a rubber band, elastic.
06:02The way muscles respond to forces depends on how fast those forces are applied.
06:06If you stretch or compress a muscle quickly, it makes the muscle stiffer compared to a slower stretch.
06:13You can mostly see this show in passive muscles.
06:16The motor cortex, an area of the frontal lobe, on one side of your brain is responsible for controlling the
06:22muscles on the opposite side of your body.
06:24So the right side controls the movement of muscles on your left side and vice versa.
06:29To make muscle movement happen, the brain sends signals through the spinal cord and into the peripheral nervous system, which
06:35connects to your muscles.
06:37This communication pathway allows your brain to control and coordinate movements throughout your body.
06:43When it comes to more complex activities, where whole groups of muscles need to work hard, like shooting a jump
06:50shot in basketball,
06:51the messages sent from the brain become more complex.
06:56The brain has to activate a series of instructions to engage various muscles and achieve the desired movement.
07:03Before you pack your gym bag to work on your muscles like there's no tomorrow, hold on a sec.
07:08These little guys enjoy bedtime probably even more than you do.
07:12When you enter deep sleep, your hardworking muscles get the opportunity to relax.
07:16Your blood circulation improves, and the hormones that help repair and restore tissues go out to play.
07:23So don't cancel your gym appointment, but don't forget that some good and sound sleep is what really lets your
07:28muscles rejuvenate and expand.
07:33Unlike our primate pals, many people still have these foot arches.
07:37They help us move.
07:39This arch is like a built-in shock absorber for your feet.
07:42It's what allows us to bounce.
07:45There's another one.
07:46It's called the transverse arch, running side to side on the top of your foot.
07:51Think of it like a bridge that helps keep your foot in shape.
07:55Research says this arch is a big deal, too.
07:58It's responsible for about 40% of your foot's stiffness.
08:02Simply put, it's like the scaffolding that holds your foot together.
08:06When scientists snipped the transverse arch, the foot lost a lot of its firmness.
08:11But when they cut the bottom arch, it wasn't that dramatic.
08:15So, is it a modern human thing?
08:18Nope.
08:19These arches didn't just pop up yesterday.
08:21The transverse arch has been around for 3 million years.
08:25The bottom arch showed up about 1.8 million years ago.
08:30We might as well continue with another element of our feet before moving up to other parts.
08:35Our pinky toes are also more important than they seem.
08:39Whether you were born without one or have lost it, you can still walk.
08:43But pinky ones are important for keeping us on our feet.
08:47They provide balance.
08:48Inside your foot, you've got 26 bones that team up to make sure you don't topple over.
08:54Small toe is a part of this balance work.
08:57Our ape ancestors needed their toes to grab, claw, and swing from trees.
09:02Today, we've traded our tree climbing skills for comfy couches and binge watches.
09:08Okay, let's move up a bit and talk about the appendix.
09:11You might think that it's useless, but nope.
09:14When a human is in their mommy's belly, this organ starts to do its job.
09:19Around the 11th week of development, it starts churning out special cells that produce helpful hormones and compounds.
09:27The appendix helps train our immune system's troops, ensuring they're top-notch defenders.
09:32It also collects all sorts of foreign substances, aka antigens, from our digestive tract.
09:38Yet, as diets evolved, this piece shrank like a deflating balloon.
09:44Unlike most other vestigial structures, the appendix isn't always harmless.
09:50It can turn into an angry little fireball.
09:53By the way, vestigial organs are the ones that have lost their primary ancestral function.
10:00These structures mostly lack an apparent purpose.
10:03Another famous vestigial example is wisdom teeth.
10:06Those are pointless, and have been causing us trouble for ages.
10:10Yet, nearly 95% of us have them.
10:13And 90% might even have to deal with the drama of an impacted wisdom tooth at some point.
10:18If you don't have them, you might consider yourself lucky.
10:21Here's an additional interesting fact about wisdom teeth.
10:25Even though your teeth have a mineral softer than what's in shark teeth, new tests show that they're just as
10:31resilient.
10:32The coating on shark teeth is actually similar in hardness to the enamel on a human wisdom tooth.
10:38It's because their surfaces are made of mineral crystals held together by proteins.
10:43These prevent them from shattering easily upon impact.
10:46So the difference in how we and sharks use our teeth comes down to their design, not their toughness.
10:54Anthropologists have examined ancient skeletons.
10:56They think our ancestors needed these extra teeth to chew tough stuff, like roots and raw meat.
11:03Back then, those extra teeth came in handy.
11:07But then, we discovered cooking.
11:09And suddenly, our food got softer, and our jaws got smaller.
11:15Geneticists have their own take on this subject.
11:17It involves a gene called MYH16, which seems to play a role in both brain size and jaw characteristics.
11:26Yet, the exact part it played in our evolutionary story is still a bit of a mystery.
11:32Now, another pointless thing is the eyelid.
11:35Well, not the regular eyelid.
11:38You know, that little pink thing hiding in the corner of your eye.
11:41Birds and some other furry pals use it to fend off dust and debris trying to mess with their eyes.
11:48But in us humans, it's mostly vestigial.
11:52Meet the palmaris longus.
11:54About 85% of us still carry it around.
11:58Maybe you also have it.
12:00You can test it by putting your hand on a flat surface and making your pinky and thumb meet.
12:06If you spot a little tendon band doing the limbo in the middle of your wrist,
12:10then you've found it.
12:12It was there for gripping stuff and swinging around like Tarzan.
12:16We can carry on with the grasping trick.
12:19Even before you're born, around 16 weeks into your time inside your mom's tummy,
12:25you're already practicing your grip.
12:27You start by grabbing onto the umbilical cord.
12:30When you finally arrive in the world,
12:33this reflex helps you hold onto things.
12:35Fun fact, small monkeys can hang on one hand for ages, thanks to a similar trick.
12:42Yet, we humans lose this super grip when we're around 3 months old.
12:47When you're still in your mother's womb, you also have a mini tail.
12:51But as you grow, it disappears,
12:54and those tiny vertebrae become your tailbone or coccyx.
12:58Humans and our ape cousins don't have tails like other animals.
13:02Our ears, too, have vestigial muscles.
13:06They help animals hear better and express their feelings.
13:10But in humans, these ear muscles don't do much.
13:14We've figured out other ways to listen and show our emotions.
13:18Yet, some of us can still wiggle our ears with practice.
13:23Surprisingly, toenails also count as a vestigial thing.
13:27I mean, they function as the initial line of defense.
13:30They protect the body against harmful microorganisms.
13:34In our evolutionary journey, we used our fingernails and toenails for defense,
13:38digging, and climbing.
13:40In the modern world, fingernails still come to our rescue,
13:43whether it's for peeling fruit or that sweet sensation of scratching an itch.
13:48Yet, toenails have retired.
13:50But hey, we can apply nail polish to them.
13:53For fashion's sake, they certainly work for many people.
13:57It's not just humans who have useless limbs or organs.
14:00In 1798, an anatomist examined a peculiar bird incapable of flying.
14:07He documented his observations.
14:10This avian species was none other than an ostrich.
14:14Ostriches and cassowaries are just a few examples of birds possessing vestigial wings.
14:20Anatomically speaking, these are rudimentary wings,
14:23incapable of granting flight to these hefty creatures.
14:27Yet, they aren't entirely devoid of function.
14:31They serve the purpose of maintaining balance during rapid running.
14:34Plus, they elaborate courtship displays, helping birds attract potential mates.
14:39Now, when it comes to animals, a lot of them glow, too.
14:43Around 76% of ocean animals, including jellyfish, worms, sharks, and sea stars, are bioluminescent.
14:50They have a compound called luciferin that reacts with oxygen to create light.
14:55And for them, it serves such purposes as stunning predators, attracting prey, or warning others of danger.
15:02We humans can glow, too.
15:05Unfortunately, this glow is super faint.
15:08Our eyes can't see it.
15:10Our bodies emit light.
15:12But it's about a thousand times dimmer than what our eyes can detect.
15:16Scientists found that our glow changes throughout the day.
15:20It's the faintest in the morning and the brightest in the late afternoon.
15:24Our faces glow more than the rest of our bodies.
15:27They think it's because our faces get more sun exposure and have melanin,
15:31which has components that can boost light production.
15:34Some body tricks distinguish us from the rest of the animal kingdom.
15:38For instance, do you know that humans are the only animals capable of blushing?
15:43It seems we've got the exclusive rights to this rosy-cheeked phenomenon.
15:48When we find ourselves in an embarrassing situation, our blood vessels dilate.
15:55That's what gives us those blushes.
15:58Embarrassment is a pretty complex emotion.
16:01It's all about understanding what others think of us.
16:04This might be too advanced for other animals.
16:08Interestingly, bald-uakari monkeys can also blush, but not in the same sense.
16:14For them, this is a show of their good health.
16:17Speaking of good health, we should honor our gut.
16:21Your gut includes the stomach, liver, and more.
16:24It's often called the second brain.
16:27This second brain has its own nervous system.
16:30It has a hundred million messengers.
16:33They send info to the rest of your body.
16:35Even if the gut-brain connection is cut, it keeps working.
16:39It ensures your digestive system functions on its own.
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