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Animal Infrastructure: Why You’re More Than Goo: Crash Course Biology #44
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Duration: | 12:23 |
Uploaded: | 2024-05-21 |
Last sync: | 2024-11-29 02:15 |
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MLA Full: | "Animal Infrastructure: Why You’re More Than Goo: Crash Course Biology #44." YouTube, uploaded by CrashCourse, 21 May 2024, www.youtube.com/watch?v=gAWYROgu4JU. |
MLA Inline: | (CrashCourse, 2024) |
APA Full: | CrashCourse. (2024, May 21). Animal Infrastructure: Why You’re More Than Goo: Crash Course Biology #44 [Video]. YouTube. https://youtube.com/watch?v=gAWYROgu4JU |
APA Inline: | (CrashCourse, 2024) |
Chicago Full: |
CrashCourse, "Animal Infrastructure: Why You’re More Than Goo: Crash Course Biology #44.", May 21, 2024, YouTube, 12:23, https://youtube.com/watch?v=gAWYROgu4JU. |
When you think about the body’s infrastructure, you probably think of bones. But what about the heart, the blood vessels, and the lymphatic system? In this episode of Crash Course Biology, we’ll tour the cardiovascular, lymphatic, and musculoskeletal systems, learning how all of them keep a vertebrate’s inner workings connected, powered up, and ready to move.
Introduction: The Body's Infrastructure 00:00
Blood Vessels & Capillaries 01:23
The Heart 04:05
Vivien Thomas 05:29
The Lymphatic System 07:03
The Musculoskeletal System 08:36
Review & Credits 11:04
This series was produced in collaboration with HHMI BioInteractive, committed to empowering educators and inspiring students with engaging, accessible, and quality classroom resources. Visit https://BioInteractive.org/CrashCourse for more information.
Are you an educator looking for what NGSS Standards are covered in this episode? Check out our Educator Standards Database for Biology here: https://www.thecrashcourse.com/biologystandards
Check out our Biology playlist here: https://www.youtube.com/playlist?list=PL8dPuuaLjXtPW_ofbxdHNciuLoTRLPMgB
Watch this series in Spanish on our Crash Course en Español channel here: https://www.youtube.com/playlist?list=PLkcbA0DkuFjWQZzjwF6w_gUrE_5_d3vd3
Sources: https://docs.google.com/document/d/1GLDtAXE6ekg4Chk2qN3TYbNt0pJbyaHqTqRd6QY8pd4/edit?usp=sharing
***
Crash Course is on Patreon! You can support us directly by signing up at http://www.patreon.com/crashcourse
Thanks to the following patrons for their generous monthly contributions that help keep Crash Course free for everyone forever:
Leah H., David Fanska, Andrew Woods, DL Singfield, Ken Davidian, Stephen Akuffo, Toni Miles, Steve Segreto, Kyle & Katherine Callahan, Laurel Stevens, Burt Humburg, Perry Joyce, Scott Harrison, Mark & Susan Billian, Alan Bridgeman, Breanna Bosso, Matt Curls, Jennifer Killen, Jon Allen, Sarah & Nathan Catchings, team dorsey, Bernardo Garza, Trevin Beattie, Eric Koslow, Indija-ka Siriwardena, Jason Rostoker, Siobhán, Ken Penttinen, Nathan Taylor, Barrett & Laura Nuzum, Les Aker, William McGraw, Vaso, ClareG, Rizwan Kassim, Constance Urist, Alex Hackman, Pineapples of Solidarity, Katie Dean, Stephen McCandless, Wai Jack Sin, Ian Dundore, Caleb Weeks
__
Want to find Crash Course elsewhere on the internet?
Instagram - https://www.instagram.com/thecrashcourse/
Facebook - http://www.facebook.com/YouTubeCrashCourse
Twitter - http://www.twitter.com/TheCrashCourse
CC Kids: http://www.youtube.com/crashcoursekids
Introduction: The Body's Infrastructure 00:00
Blood Vessels & Capillaries 01:23
The Heart 04:05
Vivien Thomas 05:29
The Lymphatic System 07:03
The Musculoskeletal System 08:36
Review & Credits 11:04
This series was produced in collaboration with HHMI BioInteractive, committed to empowering educators and inspiring students with engaging, accessible, and quality classroom resources. Visit https://BioInteractive.org/CrashCourse for more information.
Are you an educator looking for what NGSS Standards are covered in this episode? Check out our Educator Standards Database for Biology here: https://www.thecrashcourse.com/biologystandards
Check out our Biology playlist here: https://www.youtube.com/playlist?list=PL8dPuuaLjXtPW_ofbxdHNciuLoTRLPMgB
Watch this series in Spanish on our Crash Course en Español channel here: https://www.youtube.com/playlist?list=PLkcbA0DkuFjWQZzjwF6w_gUrE_5_d3vd3
Sources: https://docs.google.com/document/d/1GLDtAXE6ekg4Chk2qN3TYbNt0pJbyaHqTqRd6QY8pd4/edit?usp=sharing
***
Crash Course is on Patreon! You can support us directly by signing up at http://www.patreon.com/crashcourse
Thanks to the following patrons for their generous monthly contributions that help keep Crash Course free for everyone forever:
Leah H., David Fanska, Andrew Woods, DL Singfield, Ken Davidian, Stephen Akuffo, Toni Miles, Steve Segreto, Kyle & Katherine Callahan, Laurel Stevens, Burt Humburg, Perry Joyce, Scott Harrison, Mark & Susan Billian, Alan Bridgeman, Breanna Bosso, Matt Curls, Jennifer Killen, Jon Allen, Sarah & Nathan Catchings, team dorsey, Bernardo Garza, Trevin Beattie, Eric Koslow, Indija-ka Siriwardena, Jason Rostoker, Siobhán, Ken Penttinen, Nathan Taylor, Barrett & Laura Nuzum, Les Aker, William McGraw, Vaso, ClareG, Rizwan Kassim, Constance Urist, Alex Hackman, Pineapples of Solidarity, Katie Dean, Stephen McCandless, Wai Jack Sin, Ian Dundore, Caleb Weeks
__
Want to find Crash Course elsewhere on the internet?
Instagram - https://www.instagram.com/thecrashcourse/
Facebook - http://www.facebook.com/YouTubeCrashCourse
Twitter - http://www.twitter.com/TheCrashCourse
CC Kids: http://www.youtube.com/crashcoursekids
Bones are great.
Lots of animals have them. And the ones that don’t are either blobs, like jellyfish, or rockin’ a hard outside coating, like most insects.
But animals need a lot more than a skeleton to keep their goo sacks gooin’. Inside us, there are incredible systems that act as the body’s roads, bridges, and structures. Like, take blood vessels.
Humans have 60 thousand miles of them inside our bodies for oxygen and nutrients to travel along. That windy internal passage is long enough to wrap all the way around the earth twice! I think my brain is really just now coming to grips with just how astounding that is!
This is really what parents should tell kids when they won’t eat their veggies. “Eat your broccoli now Thurston, so your blood vessels can grow long enough to wrap around the earth twice.” So, today we’re going to sing the praises of the cardiovascular and lymphatic systems, give our muscles the chance to flex, and sure, we’ll talk some more about bones, too. All systems that serve as infrastructure for these soft bundles of tissues and organs we call bodies. Hi, I’m Dr.
Sammy, your friendly neighborhood entomologist, and this is Crash Course Biology. Speaking of flexing, y’all mind if I flex my theme music? [THEME MUSIC] After our respiratory and digestive systems have done the job of bringing energy into our bodies, we multicellular organisms need a system to transport life-giving oxygen and nutrients to all the cells. A meal delivery service, if you will.
For that, we can thank the cardiovascular system, home to our heart and blood vessels. See, inside of all us animals with backbones and skeletal systems, or vertebrates, are those miles and miles of vessels that make up our bloodstream. The bloodstream flows like a river, and there are a lot of boats on this river, including hormones, gases, specialized cells, and more, all traveling to wherever they’re needed.
But perhaps the most important boat in the bloodstream is the SS Red Blood Cell, which carries oxygen from the lungs to the rest of the body—and picks up carbon dioxide on the return trip to be exhaled. Blood also helps deliver nutrients from the digestive system to cells, and removes waste products from those cells to be released through the urinary system. So, the next time you have to pee halfway into a movie, you can thank the efficient rivers of the cardiovascular system.
Now, red blood cells usually don’t leave the system. If they do, it probably means something’s gone wrong and you’re bleeding. Thankfully, animals don’t have to bleed to get nutrients and waste in and out of the bloodstream.
Instead, we have special vessels called capillaries that are found all over the body. You can think of it like this: if the bloodstream is a river; capillaries are the ports. They’re the points of departure or arrival along the bloodstream for vital nutrients, gases, or waste.
And they’re littering the shores of your bloodstream, popping up anywhere that’s in need of resources. Like, after a good brunch, capillaries in your intestines pick up nutrients that then travel through your bloodstream to where they’re needed. And when you breathe, capillaries in your lungs pick up and drop off oxygen and carbon dioxide.
Capillaries are so good at this because they’re typically super thin, so blood is forced to slow down as it passes through them. This allows time for nutrients and other important stuff to pass out of the capillary’s thin wall and into the body’s cells. Often, molecules flow automatically from areas of high concentration to areas of low concentration in a process called diffusion.
Diffusion also explains why you can sometimes smell your neighbor’s cooking. The molecules carrying the smell were highly concentrated in their kitchen, and they spread out from there. It’s the same principle in many of your body’s internal systems — including your capillaries.
If there’s a high concentration of carbon dioxide in the blood and a low concentration in your lungs, that CO2 will pass out of the capillary and spread into your lungs to be exhaled. The same goes for oxygen and most nutrients. That’s pretty cool, but the beating heart of your cardiovascular system is — well, it’s your heart.
And all that blood is kept flowing by a muscle about the size of your fist. The human heart pumps blood along two circuits: one from the heart to the lungs and back, which provides oxygen to the blood and removes CO2 from it. And a second circuit goes from the heart to everywhere in the body and back again, to transport oxygen, nutrients, and waste.
Hearts look different in different animals. For instance, bird and mammal hearts have four chambers for sending and receiving blood, but reptiles have three, and fish have two. Then there are invertebrates, which don’t have our fancy backbones, and their hearts can vary even more wildly from ours.
For example, octopuses have three /entire hearts/! Just one reason why I’m low-key obsessed with these cephalopods! I’m an official card-carrying member of the OctoNation fandom.
Regardless of spine status, all those different hearts are doing the same thing: pumping blood throughout the body. And this is an all-important task. Without the heart beating, the rest of the system is kind of like an abandoned waterpark.
The tubes are all in place, but nothing’s flowing through ‘em. So, unsurprisingly, a lot of research focuses on how to fix the heart when things go wrong. And on that note, would you join me for an interlude as I’ve got two tickets to the Theater of Life… [CHAPTER 4 - VIVIEN THOMAS] When Vivien Thomas graduated high school in 1929, he knew he wanted to be a doctor.
But that was easier said than done. Because, in the 1920s, Black Americans were banned from many medical schools and careers. But Thomas still managed to get a foot in the door, when a surgeon named Dr. Alfred Blalock hired him as a research technician just a year out of high school.
This move would change the world of heart surgery forever. Thirteen years later, Blalock was approached by a cardiologist interested in blue baby syndrome—a heart complication that prevents a baby from getting enough oxygen, so their skin turns blue. At the time, 25 percent of babies born with this condition died before their first birthday, and 70 percent by age ten.
Thomas came up with a procedure to fix this heart issue and spent two years demonstrating its safety. Then, in 1944, he coached Blalock through the surgery, which worked perfectly. Except, when this discovery was published in a major scientific journal, Thomas’s name was left out.
It was just called the “Blalock-Taussig” procedure after Blalock and the cardiologist. But many people are now starting to call it the “Blalock-Taussig-Thomas” procedure, to correct the erasure of Thomas’s major role in saving lives. Thomas went on to become a surgery instructor and supervise labs, and in 1976, he received an honorary doctorate degree.
The cardiovascular system — and the heart that powers it — might be the body’s biggest transportation network, but animals have another transportation system. And to understand it, we have to circle back around to those capillaries. You see, fluids from the bloodstream are always leaving through the capillaries and traveling into the space between cells.
Here, they’re considered interstitial fluid. Cells take up what they need from the interstitial fluid, but they don’t use it all. Kind of like how your house plant sucks up some of the water that you pour into its soil.
But it often doesn’t use all the water; some ends up in the tray beneath the plant. If too much water ended up in that tray, the roots could become waterlogged and the plant would be in trouble. And there’s a similar risk with too much interstitial fluid.
You see, about three liters of the stuff trickles from your capillaries into your tissues every day. And if that extra fluid doesn’t get back into your blood, your tissues are going to swell up, and your blood is going to be short on fluid. So, something has to regulate this system, making sure that extra interstitial fluid high-tails it back into the bloodstream.
That “something” is the lymphatic system: the cardiovascular system’s quieter—but equally important—coworker. Through a series of vessels and tubes all throughout your body, the lymphatic system takes the extra interstitial fluid and dumps it back into the bloodstream. But it’s not just the off-ramp for extra fluids.
The lymphatic system also absorbs fat from the digestive system, which is too big for nearby capillaries to pick up. And it plays an important role in the immune system, but we’ll get into that next episode. So, overall, the lymphatic system is a key player that keeps multiple other systems running.
Sure, it’s not as marketable as the skeletal system or as flashy as the cardiovascular, but without it, those others would be in a world of trouble. Now, when it comes to us vertebrates, there’s one system that helps everything from blowfish to buffalo make their way through the world. That’s right, we’ve finally made our way back to bones—the bones and muscles of the musculoskeletal system.
This is a mash-up of two other systems that work super closely together: the muscular system, aka muscles, and the skeletal system, aka the skeleton. And this combo is what allows vertebrates to move and gives them structure. The structure part is easy enough to see…or at least, conceptualize.
If your bones are actually visible right now, pause the video and go see a doctor! In any case, bones provide a firm support system for the big sack of water and salts that is you, so that you don’t collapse into a pile of mush. But there’s more to bones than meets the eye.
Like, they can help store excess minerals in the body and protect our squishy internal organs – but, they’re also the birthplace of blood cells! Yeah, blood cells! When you visit a skeleton in a museum, it can be easy to think of bones as biology’s rocks.
But they’re made of living cells surrounded by a super hard exterior. Just like other organs, bones have lots of stuff inside them, like blood vessels, tissues, and more. They’re filled with a specific kind of tissue, called bone marrow, that’s soft and spongy — and it’s where most red blood cells are made!
But unlike the animatronic skeletons in your neighbor’s Halloween decor, bones can’t move on their own. They need muscles to get anywhere. Many muscles attach to bones, and they’re basically playing tug-of-war with your skeleton any time you try to move.
You see, muscles can contract and relax, but they’re generating force only when they’re contracting, or bunching up. In other words, they only pull to move your body, not push. So, when you move your arm up, like this, your muscles are pulling it up.
But when you put it back down, those same muscles aren’t pushing it down. Different muscles are pulling it down. That’s because our muscles work in pairs.
When one contracts, the other relaxes, allowing for some pretty coordinated movements. And most of our biggest movements happen at joints, where two bones come together. There, groups of muscles contract and relax, allowing you to do, well, all kinds of stuff.
I think I smell a montage. [Rocky-style training montage] Bones and muscles get a lot of the glory for keeping our complex bodies together. But we’re so much more than that! Animals work because all of these systems — cardiovascular, lymphatic, musculoskeletal, and more — work together.
They’re the foundation that our bodies are built on — not just stopping us from being sacks of motionless goo, but also providing our bodies with oxygen and vital nutrients while helping us get rid of waste. On top of that, our bodies have systems for healing and warding off infections. But more on that next time.
I’ll see you then. Peace! This series was produced in collaboration with HHMI BioInteractive.
If you’re an educator, visit BioInteractive.org/CrashCourse for classroom resources and professional development related to the topics covered in this course. Thanks for watching this episode of Crash Course Biology which was filmed at our studio in Indianapolis, Indiana, and was made with the help of all these nice people. If you want to help keep Crash Course free for everyone, forever, you can join our community on Patreon.
Lots of animals have them. And the ones that don’t are either blobs, like jellyfish, or rockin’ a hard outside coating, like most insects.
But animals need a lot more than a skeleton to keep their goo sacks gooin’. Inside us, there are incredible systems that act as the body’s roads, bridges, and structures. Like, take blood vessels.
Humans have 60 thousand miles of them inside our bodies for oxygen and nutrients to travel along. That windy internal passage is long enough to wrap all the way around the earth twice! I think my brain is really just now coming to grips with just how astounding that is!
This is really what parents should tell kids when they won’t eat their veggies. “Eat your broccoli now Thurston, so your blood vessels can grow long enough to wrap around the earth twice.” So, today we’re going to sing the praises of the cardiovascular and lymphatic systems, give our muscles the chance to flex, and sure, we’ll talk some more about bones, too. All systems that serve as infrastructure for these soft bundles of tissues and organs we call bodies. Hi, I’m Dr.
Sammy, your friendly neighborhood entomologist, and this is Crash Course Biology. Speaking of flexing, y’all mind if I flex my theme music? [THEME MUSIC] After our respiratory and digestive systems have done the job of bringing energy into our bodies, we multicellular organisms need a system to transport life-giving oxygen and nutrients to all the cells. A meal delivery service, if you will.
For that, we can thank the cardiovascular system, home to our heart and blood vessels. See, inside of all us animals with backbones and skeletal systems, or vertebrates, are those miles and miles of vessels that make up our bloodstream. The bloodstream flows like a river, and there are a lot of boats on this river, including hormones, gases, specialized cells, and more, all traveling to wherever they’re needed.
But perhaps the most important boat in the bloodstream is the SS Red Blood Cell, which carries oxygen from the lungs to the rest of the body—and picks up carbon dioxide on the return trip to be exhaled. Blood also helps deliver nutrients from the digestive system to cells, and removes waste products from those cells to be released through the urinary system. So, the next time you have to pee halfway into a movie, you can thank the efficient rivers of the cardiovascular system.
Now, red blood cells usually don’t leave the system. If they do, it probably means something’s gone wrong and you’re bleeding. Thankfully, animals don’t have to bleed to get nutrients and waste in and out of the bloodstream.
Instead, we have special vessels called capillaries that are found all over the body. You can think of it like this: if the bloodstream is a river; capillaries are the ports. They’re the points of departure or arrival along the bloodstream for vital nutrients, gases, or waste.
And they’re littering the shores of your bloodstream, popping up anywhere that’s in need of resources. Like, after a good brunch, capillaries in your intestines pick up nutrients that then travel through your bloodstream to where they’re needed. And when you breathe, capillaries in your lungs pick up and drop off oxygen and carbon dioxide.
Capillaries are so good at this because they’re typically super thin, so blood is forced to slow down as it passes through them. This allows time for nutrients and other important stuff to pass out of the capillary’s thin wall and into the body’s cells. Often, molecules flow automatically from areas of high concentration to areas of low concentration in a process called diffusion.
Diffusion also explains why you can sometimes smell your neighbor’s cooking. The molecules carrying the smell were highly concentrated in their kitchen, and they spread out from there. It’s the same principle in many of your body’s internal systems — including your capillaries.
If there’s a high concentration of carbon dioxide in the blood and a low concentration in your lungs, that CO2 will pass out of the capillary and spread into your lungs to be exhaled. The same goes for oxygen and most nutrients. That’s pretty cool, but the beating heart of your cardiovascular system is — well, it’s your heart.
And all that blood is kept flowing by a muscle about the size of your fist. The human heart pumps blood along two circuits: one from the heart to the lungs and back, which provides oxygen to the blood and removes CO2 from it. And a second circuit goes from the heart to everywhere in the body and back again, to transport oxygen, nutrients, and waste.
Hearts look different in different animals. For instance, bird and mammal hearts have four chambers for sending and receiving blood, but reptiles have three, and fish have two. Then there are invertebrates, which don’t have our fancy backbones, and their hearts can vary even more wildly from ours.
For example, octopuses have three /entire hearts/! Just one reason why I’m low-key obsessed with these cephalopods! I’m an official card-carrying member of the OctoNation fandom.
Regardless of spine status, all those different hearts are doing the same thing: pumping blood throughout the body. And this is an all-important task. Without the heart beating, the rest of the system is kind of like an abandoned waterpark.
The tubes are all in place, but nothing’s flowing through ‘em. So, unsurprisingly, a lot of research focuses on how to fix the heart when things go wrong. And on that note, would you join me for an interlude as I’ve got two tickets to the Theater of Life… [CHAPTER 4 - VIVIEN THOMAS] When Vivien Thomas graduated high school in 1929, he knew he wanted to be a doctor.
But that was easier said than done. Because, in the 1920s, Black Americans were banned from many medical schools and careers. But Thomas still managed to get a foot in the door, when a surgeon named Dr. Alfred Blalock hired him as a research technician just a year out of high school.
This move would change the world of heart surgery forever. Thirteen years later, Blalock was approached by a cardiologist interested in blue baby syndrome—a heart complication that prevents a baby from getting enough oxygen, so their skin turns blue. At the time, 25 percent of babies born with this condition died before their first birthday, and 70 percent by age ten.
Thomas came up with a procedure to fix this heart issue and spent two years demonstrating its safety. Then, in 1944, he coached Blalock through the surgery, which worked perfectly. Except, when this discovery was published in a major scientific journal, Thomas’s name was left out.
It was just called the “Blalock-Taussig” procedure after Blalock and the cardiologist. But many people are now starting to call it the “Blalock-Taussig-Thomas” procedure, to correct the erasure of Thomas’s major role in saving lives. Thomas went on to become a surgery instructor and supervise labs, and in 1976, he received an honorary doctorate degree.
The cardiovascular system — and the heart that powers it — might be the body’s biggest transportation network, but animals have another transportation system. And to understand it, we have to circle back around to those capillaries. You see, fluids from the bloodstream are always leaving through the capillaries and traveling into the space between cells.
Here, they’re considered interstitial fluid. Cells take up what they need from the interstitial fluid, but they don’t use it all. Kind of like how your house plant sucks up some of the water that you pour into its soil.
But it often doesn’t use all the water; some ends up in the tray beneath the plant. If too much water ended up in that tray, the roots could become waterlogged and the plant would be in trouble. And there’s a similar risk with too much interstitial fluid.
You see, about three liters of the stuff trickles from your capillaries into your tissues every day. And if that extra fluid doesn’t get back into your blood, your tissues are going to swell up, and your blood is going to be short on fluid. So, something has to regulate this system, making sure that extra interstitial fluid high-tails it back into the bloodstream.
That “something” is the lymphatic system: the cardiovascular system’s quieter—but equally important—coworker. Through a series of vessels and tubes all throughout your body, the lymphatic system takes the extra interstitial fluid and dumps it back into the bloodstream. But it’s not just the off-ramp for extra fluids.
The lymphatic system also absorbs fat from the digestive system, which is too big for nearby capillaries to pick up. And it plays an important role in the immune system, but we’ll get into that next episode. So, overall, the lymphatic system is a key player that keeps multiple other systems running.
Sure, it’s not as marketable as the skeletal system or as flashy as the cardiovascular, but without it, those others would be in a world of trouble. Now, when it comes to us vertebrates, there’s one system that helps everything from blowfish to buffalo make their way through the world. That’s right, we’ve finally made our way back to bones—the bones and muscles of the musculoskeletal system.
This is a mash-up of two other systems that work super closely together: the muscular system, aka muscles, and the skeletal system, aka the skeleton. And this combo is what allows vertebrates to move and gives them structure. The structure part is easy enough to see…or at least, conceptualize.
If your bones are actually visible right now, pause the video and go see a doctor! In any case, bones provide a firm support system for the big sack of water and salts that is you, so that you don’t collapse into a pile of mush. But there’s more to bones than meets the eye.
Like, they can help store excess minerals in the body and protect our squishy internal organs – but, they’re also the birthplace of blood cells! Yeah, blood cells! When you visit a skeleton in a museum, it can be easy to think of bones as biology’s rocks.
But they’re made of living cells surrounded by a super hard exterior. Just like other organs, bones have lots of stuff inside them, like blood vessels, tissues, and more. They’re filled with a specific kind of tissue, called bone marrow, that’s soft and spongy — and it’s where most red blood cells are made!
But unlike the animatronic skeletons in your neighbor’s Halloween decor, bones can’t move on their own. They need muscles to get anywhere. Many muscles attach to bones, and they’re basically playing tug-of-war with your skeleton any time you try to move.
You see, muscles can contract and relax, but they’re generating force only when they’re contracting, or bunching up. In other words, they only pull to move your body, not push. So, when you move your arm up, like this, your muscles are pulling it up.
But when you put it back down, those same muscles aren’t pushing it down. Different muscles are pulling it down. That’s because our muscles work in pairs.
When one contracts, the other relaxes, allowing for some pretty coordinated movements. And most of our biggest movements happen at joints, where two bones come together. There, groups of muscles contract and relax, allowing you to do, well, all kinds of stuff.
I think I smell a montage. [Rocky-style training montage] Bones and muscles get a lot of the glory for keeping our complex bodies together. But we’re so much more than that! Animals work because all of these systems — cardiovascular, lymphatic, musculoskeletal, and more — work together.
They’re the foundation that our bodies are built on — not just stopping us from being sacks of motionless goo, but also providing our bodies with oxygen and vital nutrients while helping us get rid of waste. On top of that, our bodies have systems for healing and warding off infections. But more on that next time.
I’ll see you then. Peace! This series was produced in collaboration with HHMI BioInteractive.
If you’re an educator, visit BioInteractive.org/CrashCourse for classroom resources and professional development related to the topics covered in this course. Thanks for watching this episode of Crash Course Biology which was filmed at our studio in Indianapolis, Indiana, and was made with the help of all these nice people. If you want to help keep Crash Course free for everyone, forever, you can join our community on Patreon.