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Nervous & Endocrine Systems: What Really Happens When You Step on a Lego: Crash Course Biology #46
YouTube: | https://youtube.com/watch?v=NKpkU4-Sf9A |
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View count: | 49,646 |
Likes: | 1,860 |
Comments: | 52 |
Duration: | 10:28 |
Uploaded: | 2024-06-11 |
Last sync: | 2024-12-20 19:30 |
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Citation formatting is not guaranteed to be accurate. | |
MLA Full: | "Nervous & Endocrine Systems: What Really Happens When You Step on a Lego: Crash Course Biology #46." YouTube, uploaded by CrashCourse, 11 June 2024, www.youtube.com/watch?v=NKpkU4-Sf9A. |
MLA Inline: | (CrashCourse, 2024) |
APA Full: | CrashCourse. (2024, June 11). Nervous & Endocrine Systems: What Really Happens When You Step on a Lego: Crash Course Biology #46 [Video]. YouTube. https://youtube.com/watch?v=NKpkU4-Sf9A |
APA Inline: | (CrashCourse, 2024) |
Chicago Full: |
CrashCourse, "Nervous & Endocrine Systems: What Really Happens When You Step on a Lego: Crash Course Biology #46.", June 11, 2024, YouTube, 10:28, https://youtube.com/watch?v=NKpkU4-Sf9A. |
If cells and organs never talked to each other, an animal would fall apart faster than a boy band after the popular one goes solo. Thankfully, that’s where the nervous and endocrine systems come in! In this episode of Crash Course Biology, we’ll learn how they use neurons, hormones, and more to keep animals’ bodies coordinated.
Introduction: Internal communication in animals 00:00
Why communication matters 01:01
The nervous system 01:58
What happens when you step on a Lego? 03:48
Hormones 06:19
Fight or Flight 08:01
Review & Credits 09:07
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: Internal communication in animals 00:00
Why communication matters 01:01
The nervous system 01:58
What happens when you step on a Lego? 03:48
Hormones 06:19
Fight or Flight 08:01
Review & Credits 09:07
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
Your heart is racing.
Your breathing is fast. Are you stressing over a big test? Rooting for your favorite team? Getting ready for the most epic rap battle in history!? As it turns out, our bodies have pretty similar responses for both anxiety and excitement, which is why you might feel tense during any of those situations. Those physical reactions are caused by our bodies communicating within themselves. And the more we learn about this internal communication, the better we are at understanding how we’ve survived and evolved long enough to invent pop quizzes. I mean, you’ve gotta be pretty secure as a species to introduce that kind of stressor. Hi!
I’m Dr. Sammy, your friendly neighborhood entomologist, and this is Crash Course Biology. Also, do you feel that tingle on the back of your neck. That’s your body communicating that you’re ready for this funky theme music! [THEME MUSIC] We multicellular organisms are a lot like boy bands. In a boy band, you’ve got singers that need to work together to make one super catchy song. They can’t all be solo artists doing whatever makes each of them look best. If everyone starts singing in their own key things are gonna get weird. No one will be in sync, or going in One Direction. Hehe. The same is true if you’re an organism made of lots of cells. To grow and develop, maintain an immune system, and respond to the ever-changing world around you, your cells and organs have to create some beautiful harmonies, working together for the good of the group – in this case, your body.
Otherwise, things will fall apart faster than the career of a solo Jonas Brother. Vertebrates, or animals with backbones like yours truly, have two main systems for making this happen: the nervous system and the endocrine system. You can learn more about the nitty-gritty of how they work back in episode 25, but right now we’re gonna take more of a bird’s eye view.
Let’s start with the nervous system, which includes the brain, the spinal cord, and the spidery collection of nerves traveling from an animal’s head to its toes. Or its tail fin. This system has three main jobs: Collecting information about the environment inside and outside the body. Processing that information in the central nervous system — aka the brain and spinal cord. And responding to that information by sending signals to various cells. Consider this scenario: You walk into class, and see “pop quiz” written on the board. The sense of sight is one of the ways your nervous system collects information. That information goes from your eyes to your brain, which processes those words and the fact that you definitely didn’t do the reading. In response, your brain sends signals to the rest of your body that it’s panic time, and suddenly, your heart is going so fast, that your smartwatch thinks you’re exercising.
In real time, though, we almost never notice this happening. We read “pop quiz” and, boom: It’s all panic, no disco. That’s because the signals in the nervous system can travel fast — anywhere from half a meter per second to 120 meters per second. This is also why you can usually catch your phone the second it starts to fall, and why a fish doesn’t need to stare at a shark for long before realizing they should bolt. That said, the nervous system is mostly for short-term responses in the body, not long-term ones.
It’s great for a high-five or a thumbs up, not so useful when we need to regulate our hormonal cycles. Additionally, not every cell can talk to the nervous system. This group text is limited to special cellular messengers called neurons, and any cell that can get signals from neurons, like muscle cells. And even then, the neurons are basically whispering: so to actually hear the message, a cell has to be right next door. Let’s see this in action, over in the Thought Bubble… You’ve just stepped on a LEGO. My condolences. The moment your foot landed on that colorful torture device, sensory receptors that branch from neurons in your feet sounded the alarm: This hurts. A lot.
It can seem instantaneous, but for a merciful fraction of a second, your brain doesn’t know about the LEGO. Cue the slo-mo. The signal from your sensory receptors has to first travel along your neurons from your foot to your brain. When the message reaches the end of one neuron, it encounters a tiny gap called a synapse. To keep the message going, neurons release molecules called neurotransmitters, which carry the message across the gap and on to the next neuron. And the next and the next, like a line of dominoes falling over, until the signal hits your brain. Once that last domino falls, it’s goodbye bliss, hello pain. Your brain uses that pain as data and tells your body to move to safety by sending a signal to your muscles, also known as a motor output. And as fast as you can, you escape to a clear patch of floor.
Let’s just hope no one has left a rogue banana peel behind. Thanks, Thought Bubble! Our sensory receptors are always taking in information about what we see, hear, taste, and touch — plus information about things like balance and what’s going on /inside/ our bodies, from our temperature to our blood pressure. Some animals even have sensory receptors that give them information about electric and magnetic fields, like the internal magnetic compass that helps monarch butterflies navigate nearly 3,000 miles each year to Mexico! Though we’re pretty sure humans don’t have those…but, research is ongoing. In any case, this information is all used in more or less the same way. The signals from the receptors travel along neurons, jump synapses, get processed by the central nervous system, and then trigger a response. This kind of communication helps animals survive in some obvious ways, like letting us know if we touch a hot surface or that danger is around if we hear the roar of a predator. And some less obvious ways, like figuring out what foods are safe to eat based on how they taste. So, sweet foods tell us something is rich in energy-packed carbs. Salty equals minerals.
Sour means acids, like in rotting food. And many plant poisons are bitter. When the central nervous system processes these sensations, our brains learn what’s safe to eat and what’s probably bad for us. While the nervous system is all about getting things done fast, like tasting a flavor as soon as it hits your tongue, we know that it isn’t so good at playing the long game. Thankfully, that’s where the endocrine system comes in handy. In humans, it includes glands and organs throughout the body, from the hypothalamus in the brain to the adrenal glands on top of the kidneys, to reproductive organs. It works more slowly than the nervous system, but the results often stick around a lot longer. This is because the endocrine system doesn’t primarily rely on neurons: it sends messages using hormones, instead. Hormones are basically just molecules secreted into the blood, which carries them to organs and tissues to make things happen. You may have heard about estrogen or testosterone, human reproductive hormones – but those are just the tip of the hormonal iceberg.
Others make you sleepy, some respond to stress, and still, others regulate how much glucose and calcium are kickin’ around your bloodstream. Like with the nervous system, not every cell can communicate with every type of hormone. But the ones that can interpret the signal are called target cells. It’s like how if you speak to me in Dothraki instead of English, I just won’t get the message, no matter how many times you repeat yourself. But unlike with the nervous system, a target cell doesn’t have to be right next to the gland releasing the hormone to get the message. Hormones can hop on the bloodstream highway and reach a target cell anywhere in the body. This system takes a little longer to ramp up, but once it does, the changes tend to last longer, too. For instance: the hormone adrenaline helps get your body ready for stressful events by sending a Big Time Rush of blood to up your heart rate and prep your muscles for exertion – among other things. As you’re being strapped in to a roller coaster, it might take a minute for your body to realize what’s about to happen and start sending out adrenaline — and on the flip side, even once you’re off the ride and toddling toward the nearest bathroom, it’ll take your heart a few minutes to come back down.
That’s hormonal communication at work! And you might be wondering, “Dr. Sammy, How does my endocrine system know I’m about to get on that roller coaster anyway?
There aren’t endocrine glands in my eyeballs.” Well, this is where the endocrine and nervous systems team up. They work together to send both fast and slow messages around the body. For example, some hormones can act like neurotransmitters, and vice-versa: the nervous system has cells that can make endocrine glands release hormones. So, say a gazelle smells a lion on the wind. The signal hits the gazelle’s brain and its central nervous system shoots a message to the muscles to get out of there. But a signal also goes to the gazelle’s adrenal glands in their endocrine system, giving them the cue to release adrenaline and get their heart rate and breathing up so they’re ready to escape. Unfortunately, it also kicks in when you have to take a test you haven’t studied for. Your body thinks you’re in danger, and fully opens the adrenaline taps. You might even hear this referred to as your body’s “fight or flight” response. But, uh, don’t try and fight your test, you got this, you got this.
The good news is, like we mentioned in the intro, this system also kicks in when you’re super excited. In fact, some psychologists have suggested that one way to fight anxiety is to think about stuff you’re nervous about as if it’s exciting instead. Our bodies’ internal communication systems, from the nervous to the endocrine, have helped us be aware of, and respond to, our environments, keeping us from feeling like the new kids on the block every time something changes. And we can also learn to use these systems to our advantage, like understanding how to stop pop quizzes from freaking us out… even if only a little. In our next episode, we’re going to find out where babies come from. Yup, we’ll be talking reproduction. I’ll see ya 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. ---
Your breathing is fast. Are you stressing over a big test? Rooting for your favorite team? Getting ready for the most epic rap battle in history!? As it turns out, our bodies have pretty similar responses for both anxiety and excitement, which is why you might feel tense during any of those situations. Those physical reactions are caused by our bodies communicating within themselves. And the more we learn about this internal communication, the better we are at understanding how we’ve survived and evolved long enough to invent pop quizzes. I mean, you’ve gotta be pretty secure as a species to introduce that kind of stressor. Hi!
I’m Dr. Sammy, your friendly neighborhood entomologist, and this is Crash Course Biology. Also, do you feel that tingle on the back of your neck. That’s your body communicating that you’re ready for this funky theme music! [THEME MUSIC] We multicellular organisms are a lot like boy bands. In a boy band, you’ve got singers that need to work together to make one super catchy song. They can’t all be solo artists doing whatever makes each of them look best. If everyone starts singing in their own key things are gonna get weird. No one will be in sync, or going in One Direction. Hehe. The same is true if you’re an organism made of lots of cells. To grow and develop, maintain an immune system, and respond to the ever-changing world around you, your cells and organs have to create some beautiful harmonies, working together for the good of the group – in this case, your body.
Otherwise, things will fall apart faster than the career of a solo Jonas Brother. Vertebrates, or animals with backbones like yours truly, have two main systems for making this happen: the nervous system and the endocrine system. You can learn more about the nitty-gritty of how they work back in episode 25, but right now we’re gonna take more of a bird’s eye view.
Let’s start with the nervous system, which includes the brain, the spinal cord, and the spidery collection of nerves traveling from an animal’s head to its toes. Or its tail fin. This system has three main jobs: Collecting information about the environment inside and outside the body. Processing that information in the central nervous system — aka the brain and spinal cord. And responding to that information by sending signals to various cells. Consider this scenario: You walk into class, and see “pop quiz” written on the board. The sense of sight is one of the ways your nervous system collects information. That information goes from your eyes to your brain, which processes those words and the fact that you definitely didn’t do the reading. In response, your brain sends signals to the rest of your body that it’s panic time, and suddenly, your heart is going so fast, that your smartwatch thinks you’re exercising.
In real time, though, we almost never notice this happening. We read “pop quiz” and, boom: It’s all panic, no disco. That’s because the signals in the nervous system can travel fast — anywhere from half a meter per second to 120 meters per second. This is also why you can usually catch your phone the second it starts to fall, and why a fish doesn’t need to stare at a shark for long before realizing they should bolt. That said, the nervous system is mostly for short-term responses in the body, not long-term ones.
It’s great for a high-five or a thumbs up, not so useful when we need to regulate our hormonal cycles. Additionally, not every cell can talk to the nervous system. This group text is limited to special cellular messengers called neurons, and any cell that can get signals from neurons, like muscle cells. And even then, the neurons are basically whispering: so to actually hear the message, a cell has to be right next door. Let’s see this in action, over in the Thought Bubble… You’ve just stepped on a LEGO. My condolences. The moment your foot landed on that colorful torture device, sensory receptors that branch from neurons in your feet sounded the alarm: This hurts. A lot.
It can seem instantaneous, but for a merciful fraction of a second, your brain doesn’t know about the LEGO. Cue the slo-mo. The signal from your sensory receptors has to first travel along your neurons from your foot to your brain. When the message reaches the end of one neuron, it encounters a tiny gap called a synapse. To keep the message going, neurons release molecules called neurotransmitters, which carry the message across the gap and on to the next neuron. And the next and the next, like a line of dominoes falling over, until the signal hits your brain. Once that last domino falls, it’s goodbye bliss, hello pain. Your brain uses that pain as data and tells your body to move to safety by sending a signal to your muscles, also known as a motor output. And as fast as you can, you escape to a clear patch of floor.
Let’s just hope no one has left a rogue banana peel behind. Thanks, Thought Bubble! Our sensory receptors are always taking in information about what we see, hear, taste, and touch — plus information about things like balance and what’s going on /inside/ our bodies, from our temperature to our blood pressure. Some animals even have sensory receptors that give them information about electric and magnetic fields, like the internal magnetic compass that helps monarch butterflies navigate nearly 3,000 miles each year to Mexico! Though we’re pretty sure humans don’t have those…but, research is ongoing. In any case, this information is all used in more or less the same way. The signals from the receptors travel along neurons, jump synapses, get processed by the central nervous system, and then trigger a response. This kind of communication helps animals survive in some obvious ways, like letting us know if we touch a hot surface or that danger is around if we hear the roar of a predator. And some less obvious ways, like figuring out what foods are safe to eat based on how they taste. So, sweet foods tell us something is rich in energy-packed carbs. Salty equals minerals.
Sour means acids, like in rotting food. And many plant poisons are bitter. When the central nervous system processes these sensations, our brains learn what’s safe to eat and what’s probably bad for us. While the nervous system is all about getting things done fast, like tasting a flavor as soon as it hits your tongue, we know that it isn’t so good at playing the long game. Thankfully, that’s where the endocrine system comes in handy. In humans, it includes glands and organs throughout the body, from the hypothalamus in the brain to the adrenal glands on top of the kidneys, to reproductive organs. It works more slowly than the nervous system, but the results often stick around a lot longer. This is because the endocrine system doesn’t primarily rely on neurons: it sends messages using hormones, instead. Hormones are basically just molecules secreted into the blood, which carries them to organs and tissues to make things happen. You may have heard about estrogen or testosterone, human reproductive hormones – but those are just the tip of the hormonal iceberg.
Others make you sleepy, some respond to stress, and still, others regulate how much glucose and calcium are kickin’ around your bloodstream. Like with the nervous system, not every cell can communicate with every type of hormone. But the ones that can interpret the signal are called target cells. It’s like how if you speak to me in Dothraki instead of English, I just won’t get the message, no matter how many times you repeat yourself. But unlike with the nervous system, a target cell doesn’t have to be right next to the gland releasing the hormone to get the message. Hormones can hop on the bloodstream highway and reach a target cell anywhere in the body. This system takes a little longer to ramp up, but once it does, the changes tend to last longer, too. For instance: the hormone adrenaline helps get your body ready for stressful events by sending a Big Time Rush of blood to up your heart rate and prep your muscles for exertion – among other things. As you’re being strapped in to a roller coaster, it might take a minute for your body to realize what’s about to happen and start sending out adrenaline — and on the flip side, even once you’re off the ride and toddling toward the nearest bathroom, it’ll take your heart a few minutes to come back down.
That’s hormonal communication at work! And you might be wondering, “Dr. Sammy, How does my endocrine system know I’m about to get on that roller coaster anyway?
There aren’t endocrine glands in my eyeballs.” Well, this is where the endocrine and nervous systems team up. They work together to send both fast and slow messages around the body. For example, some hormones can act like neurotransmitters, and vice-versa: the nervous system has cells that can make endocrine glands release hormones. So, say a gazelle smells a lion on the wind. The signal hits the gazelle’s brain and its central nervous system shoots a message to the muscles to get out of there. But a signal also goes to the gazelle’s adrenal glands in their endocrine system, giving them the cue to release adrenaline and get their heart rate and breathing up so they’re ready to escape. Unfortunately, it also kicks in when you have to take a test you haven’t studied for. Your body thinks you’re in danger, and fully opens the adrenaline taps. You might even hear this referred to as your body’s “fight or flight” response. But, uh, don’t try and fight your test, you got this, you got this.
The good news is, like we mentioned in the intro, this system also kicks in when you’re super excited. In fact, some psychologists have suggested that one way to fight anxiety is to think about stuff you’re nervous about as if it’s exciting instead. Our bodies’ internal communication systems, from the nervous to the endocrine, have helped us be aware of, and respond to, our environments, keeping us from feeling like the new kids on the block every time something changes. And we can also learn to use these systems to our advantage, like understanding how to stop pop quizzes from freaking us out… even if only a little. In our next episode, we’re going to find out where babies come from. Yup, we’ll be talking reproduction. I’ll see ya 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. ---