The Skeletal System: Crash Course Anatomy & Physiology #19

Today Hank explains the skeletal system and why astronauts Scott Kelly and Mikhail Kornienko are out in space studying it. He talks about the anatomy of the skeletal system, including the flat, short, and irregular bones, and their individual arrangements of compact and spongy bone. He'll also cover the microanatomy of bones, particularly the osteons and their inner lamella. And finally, he will introduce the process of bone remodeling, which is carried out by crews of osteocytes, osteoblasts, and osteoclasts.
Pssst... we made flashcards to help you review the content in this episode! Find them on the free Crash Course App!
Download it here for Apple Devices: apple.co/3d4eyZo
Download it here for Android Devices: bit.ly/2SrDulJ
Chapters:
Introduction: Astronaut Bones 00:00
Structure of the Skeletal System: Axial & Appendicular Bones 2:33
Bone Shapes: Long, Short, Flat, and Irregular 3:11
Internal Bone Structure 3:47
Osteons and Their Lamellae 5:05
Osteoblasts and Osteoclasts 5:54
Bone Remodeling: Resorption & Apoptosis 7:28
Review 9:28
Credits 10:13
***
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[@youtubequeen4251]

Bones: Made of active connective tissue Stores calcium phosphate and minerals Hematopoiesis~blood cell production 206 bones Axial or perpendicular | | Vertical. Appendages/others Shape: Long bones longer than wide Short bones short cube like Flat bones thin ones Irregular bones can't classify Compact bone smooth Spongey porous: cross hatching supports (trabeculae)~resist stress & bone marrow red=blood cells yellow =fat Flared ends=epiphyses Middle=dialysis Middle layer=medullary cavity Osteons: cylindrical/weight baring/cented of bone (animation of bone being cut in half they are outside the center hole of bone, and appear to be like frog eggs) Each "frog egg" is a lamellae and filled with collagen fibers that run in same directions. Central canals: hold nerves and blood vessels~nutrients Lucanae spaces by central canals~astrocytes: mature bone cells that monitor and maintain your bone matrix Bone remodeling~ Osteo blasts & Osteo clasts #1. O. Blasts: bone makers Cartilage is framework for bone #2. O. Clasts: bone breakers ~resorption, apoptosis (self destruct)

[@ryja3z]

you ma'am are amazing

[@swagcat7779]

Chad

[@eileenbvanmerk2700]

As a nursing student, we constantly have to go back to anatomy and physiology to understand what happens during disease processes. These videos are super helpful and so much more convenient compared to flipping books open. Thanks so much for these! I was super impressed by how detailed and accurate your A&P videos are.

[@eileenbvanmerk2700]

+Don Blanket thank you! :)

[@sarahnaji4746]

U should make a website and u should invent exams and quizes for students!!

[@shriyasai7521]

Yes please 🙏

[@sweeflyboy]

YASSSSS!

[@iffathfatima9248]

Sarah Naji that would be awesome

[@dinhkhanh_11_21]

@@nathanyoder2379 thanks much appreciate that

[@lynns4122]

Khan Academy has quizzes on similar stuff

[@sadielikesyou]

I'm finally going to reach out and thank you via a comment... little do you know, I am a nursing student and I have used your videos for every biology course I've had to take as a quick refresher before exams. I cannot thank you enough for these videos! You explain it in a language that I can understand as opposed to the boring lull of the borderline medical journal of a textbook that I have! (why do they insist on being so sleep provoking?!) So, THANK YOU, your channel rocks and I recommend them to all my fellow students that need a quick rehash. :)

[@naomisamantha822]

Because studying anything to do with health or medicine can actually get boring but it's people like us that eventually save lives. (that's my motivation)

[@Michaliey]

I’m going through the same thing right now

[@vinsmith890]

I have a test for LPN tomorrow on integumentary and muscular/skeletal. Open book luckily but these videos help so much

[@mackenziepark5593]

This is how I'm studying for my test in biology.

[@motokid413]

+Mackenzie Park You're gonna fail

[@mackenziepark5593]

+evanups I know...

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I'm doing this to study to xD

[@Mustafa2219]

did u fail? I honestly want to know.

[@scoobty4449]

hahanice name

[@ericgonzalezmusic]

You are a life saver. U are the reason i pass anatomy

[@Juldaniacanal11]

Eric Gonzalez same

[@marvelousmimi9165]

I hope I pass this class is hard

[@LovelyyAubrey]

Eric Gonzalez That’s why I’m here trying to pass lol

[@XxXxmusicnhorsesXxXx]

I am a current A&P student in college and I couldn't understand this from my own teacher. This video definitely helped me and broke it down in a way she couldn't. Keep up with these videos! They help so much

[@julie3368]

Who else is watching this because of their teacher in quarantine

[@elinascott]

Me!

[@bakesbynoor]

lol mee

[@amyburke5867]

Or are a teacher, looking for videos for e-learning!!!! :)

[@nicolboys6958]

absolutely me!!

[@jacksonharley8550]

me

[@jordanwoods146]

You should do a video on Intramemberous and Endochandral Ossification!

[@kary2783neto]

What the heck you saying Jordan????

[@juandavila2999]

I

[@phillipanthonymeeks1997]

I'm so thankful for wonderful people like you. I can stare about my books for hours feeling frustrated about the point not getting through. Y'all make learning easy and fun! If only I could get my BS from Crash Course instead of my college.

[@chrisbailey5713]

I always do studying up before the Skeleton War I need to learn their weaknesses.

[@kid14346]

Chris Bailey According to this video, send them to space. They will consume themselves!

[@eternalaether8463]

Chris Bailey We will defeat you fuccbois

[@JoseJose-sh7fr]

Find the necromancer controlling them, without him the entire skellymen army will just be reduced to some not-so-spooky normal skeletons.

[@kid14346]

joseph clisham Plot twist! The Necromancer is a skellyman!

[@julli4821]

??? XD

[@taiipotatoie]

6:25 I can't unsee the menstrual pad 😂

[@Glaerdrune]

"We also have to figure out how to keep their bodies from consuming their own skeletons" is the most hardcore phrase I've heard all week

[@kaylaarmani1762]

Currently pulling an all nighter watching your videos for my exam tomorrow. I wish i found you at the beginning of the semester. You simplify everything greatly. Idk why professors teach a whole bunch of other junk that wont even be on the test. You get straight to the point. Love it

[@Amberhhhh]

This makes me feel like I'll be okay for my test

[@rozhinhamidizareh1076]

As a 14-year-old Iranian student, your videos really really help me to improve my English and knowledge of Biology at the same time. I watch your videos before my classes & they help me to stay on the top of my studies. Thank U!

[@tsirbuts]

I'm cramming for an anatomy test so I'm watching all the videos that I need for the test 😂

[@notPalores]

How’d it go?

[@kenny7539]

Sebastian Honores I think your a few years to late 😂😂

[@corbinmarion4616]

"Bones, well, their pretty clutch!" Without a doubt the best quote I have heard this week.

[@GabeNewellDFTBA]

This video is 2spooky4me. May Mr. Skeltal bless you with calcium

[@GabeNewellDFTBA]

Jetfuel Steelbeams Your name is 2dank4me.

[@DarkLordToturials]

Lord GabeN There is a skeleton inside you RIGHT NOW Spooked enough

[@GabeNewellDFTBA]

DarkiLordito Warn me before you spook me so hard.

[@DarkLordToturials]

Lord GabeN You must always be aware of the spookyness

[@cyanidegiraffe615]

Jetfuel Steelbeams but im not a rappa

[@LilDaz690]

Thank you for creating these classes! A&P online is pretty difficult, you make it a bit more interesting and helps a lot!

[@GuerreroAnthrax]

Currently studying to receive my NASM personal traininer certification, I'm terrible at studying but I have not only found but also understood all the material on the test through your videos, thank you so much I will definitely be contributing to the channel through patreon!

[@officerpoopnugget9989]

Crash course is probably one of the greatest channels on yt. your bio and a&p videos are gonna be my study tools for the ap

[@anthonyfosu6354]

Keep these awesome videos coming. Thank you CrashCourse A&P for being the spine to my KZbin education.

[@joanmubea5469]

This is my favorite "professor"..... Thank you!!! CrashCourse has become my favorite learning site. You explained it so well!!! Thank you!!!

[@christofferenfors3676]

Just got 5 out of 5 in my A&P Test. Is there anyway I can have a very long and seemingly akward 3way hug with u and ur dog? U guys are something else!

[@sameersheikh7603]

I'm a year late but congratulations! :D.

[@livelifeandlaff2412]

im 2 years late but congraats

[@user-zu8lq8qe2y]

Im 3 years late but yay you!

[@kimberleysinclair5904]

Thank you Hank. I am a AP Psych and Health teacher and am currently studying RHIT for a certificate from ELAC. Your videos were informative, entertaining, fast and I learned things I did not know before. I will change how I teach Health and AP Psych thanks to Hank. You are a live saver!

[@Bossyglossy1]

I can't thank you enough...Excellent analogies!!!

[@x612x]

I have waited for this SO long! Being a physical anthropologist my self I loved how you dealt with this subject :)

[@HiThere-yy8zk]

I have to do a 20 slide "slideshow" for a final. My textbook is so confusing. literally bolds and italicizes everything that is important. Crash course is the only reason I'll be passing this year. I'm just watching these videos. I won't even bother reading. Thank you Crash Course! You guys are the absolute best!

[@jrogue3710]

Hank you honestly are my favourite everything! You are helping me through SO many classes where my teacher sounds like hes speaking friggin German when explaining anatomy. When I become an RMT, you have a free massage ready for you as a thank you!!!! I had NO idea just how medical this profession is going to be or the training to get there. You are saving me!

[@jesserobin3689]

I think I'm literally crash course's biggest fan. I love this channel! If it wasn't for crash course I probably wouldn't be doing as well at varsity as I am. The visuals are also a big help. Thank you, Hank.

[@mellissamcpartland740]

Probably my favorite A&P episode so far! It was adorable yet informative!

[@unusedspacesr2740]

Im done with school and still watching crash course just for the heck of it

[@KnightsOfBellamy]

THANK YOU SO MUCH FOR THIS COURSE YOU HAVE NO IDEA HOW IMPORTANT THIS WAS FOR ME!!!

[@NykolXOXO]

I love Crash Course. Not only is it informational, it's diverting to watch and it makes learning fun

[@vanessahernandez8524]

I love watching these videos before an exam, thanks a bunch for summarizing key points to keep me focused :)!

[@shayna1182]

LOL! I live how fast you talk. I makes getting info way easier

[@mcjohnkarshavski1953]

I like the way he talks fast. It doesn't make it look long and boring to watch and learn. Good skills

[@runfreeparkour3241]

this is by far the best study resource ive ever had. Cant even describe how helpful these videos have been to me. Thanks crashcourse.

[@chrisberggren2700]

I never knew there was this much to bones. This video has greatly educated me and will definitely help as an EMT. After watching I have a much better understanding on why bones can be strengthened and how they regenerate. Thanks to osteoclasts and osteoblasts bones can become stronger!

[@barbiet2806]

I just wanted to say thank you for all your videos, and making them interesting and funny while teaching. I home school my 10 year old son, and he absolutely enjoys watching your channel

[@aarushigrover6674]

Dude you are amazing!!!! U make me love the subject! Don't listen to any negative feedback! Keep going! Love the way u talk so fast! So don't give it up!

[@sijalshrestha605]

yes.. feel same here

[@julli4821]

Yesssssss~ I fully agree!

[@brendaolson5181]

agree! make me smile while learning

[@yourroyalhighness6297]

Yes. Maximizing time is most appropriate when creating videos, and perhaps, the viewers shall adjust the speed into 0.75x if they can't understand fully because the channel never asked them to watch their videos. Hahaha, This is just my opinion.

[@pragyapandey2517]

Ekdm Sahi boli.. ❤❤

[@thelostchurches9366]

As a visual learner, I have watched over and over and over again and believed or not, it did help me a lot. Thank you so much for it.

[@deemaahmed941]

i swear you are just soooo good with explaining and representing visual models to help us understand the material ! thank you

[@childrenofthelightvelichat6074]

Any 2024 related😂😂

[@m3gal0z3r]

thank mr skeltal for calcum and strong bone

[@gracebrewer4281]

These videos are fantastic as a preview for new material and an overview before exams. The pace is perfect.

[@charlottesienna]

The osteoblasts and osteoclasts are so cute- Thank you to the graphics team for personifying Anatomy and physiology! I love it

[@geraldellis1177]

6:28 YOU GOTTA SEE IT #YOUR INSIDES WILL SHED WHEN YOU SEE IT

[@loudejesus5973]

I was supposed to make a pun about the skeleton, but none of them seemed "humerus".......... I'll be here all week.

[@geraldellis1177]

THAT WAS A OST-EONTASTIC PUN

[@micanikko]

@@geraldellis1177 That was even worse.

[@mariacyrilbaldovino1373]

Lol 😂

[@shaymaasuhair8223]

I'm here and its been 4 years... lol

[@zazhiita]

I can't believe I read a whole chapter of several pages and it took me an hour and like 15 min to kind of understand it, and then you come and BANG! in 10 minutes you explained it better than any book could ever have.

[@amandarushlow8808]

I love these videos, you guys really do a great job. Thank you for your time and effort in making these understandable.

[@twisttv4030]

Outstanding video!

[@teresaroach5677]

West boulevard rock

[@shwetakhade6531]

Thank youbso much. You made me interested into the topic.

[@kristenschmid5383]

Love Hank! He makes learning fun. I have used several videos to help teach health during distance learning. I create a Q&A to go along with the videos. Please keep making these educational videos! Thank you!

[@sintinglb]

This video is awesome! So much clearer and more interesting than real lectures

[@LizardaWizard]

There needs to be a crash course statistics because a lot of students in AP Stats are not doing so hot

[@karinaidiyatullina6897]

facts

[@pelecranileboi9011]

There is one

[@riversong7818]

Even though certain life circumstances prevented me from pursuing my lifetime goal of becoming a physician, I still love learning all I can about our miraculous human form! I am especially interested in diseases and rare diseases that can, and do, afflict our mortal selves and the advances (and failures) that so many dedicated researchers, scientists, physicians and nurses have devoted their careers to understand, and to hopefully discover the treatments and cures so many us are looking forward to! Kudo's to you all!

[@CrispyFriedPickles]

Wow, this video saved my life 😂😅 I’m definitely a visual learner because I have gained more from this short 10 minute video than I did from a 2 hour lecture in my Anatomy class! 💯🙌🏾 Thank you for making these!!!

[@jessicapyles181]

I love Crash Course!! Hank makes learning fun. Keep up the good work!!

[@SintaMukti]

thank you crash course...

[@babyz1218]

I wish you would slow down when you speak, sometimes I'm trying to process what you'd just finished saying and in that span of time you've already moved on to two other things. Thanks so much for these videos though they're really helping me with my anatomy class, I'm a visual learner xx

[@christofferenfors3676]

Seeing as they need to cram a lot of information into a concise but informative video, speed is important. You can always pause it and re watch it! :D

[@henryl3734]

baby z OMG this is same af

[@Glaerdrune]

You can change the speed of the youtube video in Settings if that helps!

[@davidschmidt6013]

Glaerdrune, you'er right, you can....it would be nice if they'd include a .75 setting though. (After all, they offer more options to speed up than to slow down.) At .5, he's just as hard to listen to but for the opposite reason. ...lol....I'm an American but teach Science here in Thailand, and would like such an option, as most of my kids are non-native speakers. Ya hear, that, KZbin admins? We want 75% playback speed!!

[@dorony1983]

You want to slow down read a book for few hours and study. Once you feel you ok with topic and need a quick refresh, watch it.. And it's going to be a great review. English is my second language and I understand him perfectly. That's actually a good practice, because in med school that's how studying should be.. Very very fast

[@Leopr1]

Very mind opening video, didn't knew the skeletal system was so complex.

[@mesmarriott127]

These crash course videos are fascinating. I'm hooked.

[@nocturne.op9]

this is sooo weird but you guys are kinda synced up with my biology class lessons...you uploaded this video on the week we started learning about bones and stuff,and the same was with the nervous system and the "vision" one,where we started learning about eyes.... reaaalllyyy curious

[@OmarZakiTopics]

co co coool

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This has got to be the best one yet! I don’t even think I have to know this stuff but I was just enthralled

[@shadooow2370]

Your way of teaching is on point. An excellent very relaxed and engaging way to teach a subject.

[@Technowhy]

This is super helpful~~ :3 (more helpful than my actual teacher...XP)

[@intertain595]

Hello- ur video really help me understand but can you please make a video more about the bone the endochondral ossification and intramembranous ossification about there formation of steps:)

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I don't usually watch stuff like this, but it was super engaging. Great content!

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This method of teaching/lecturing really works for me.

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Yay I'm not going to fail my science project after all :D

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Encouraged me to not imagine what a torsion fracture may feel like... Paused the video to take a couple of minutes to recollect myself

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These videos make me so happy ! I fangirled.....

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I LOVE CRASH COURSE SERIES THANK YOU ALL!

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Please make historical video about middle asia

[@MzShonuff123]

I wish I'd seen this before I took my test.

[@alishacarter3916]

Brilliant video! I'm a first year nursing student here in the UK and have my anatomy and physiology exam tomorrow, so its great for some last minute revision. Thanks!

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I am so grateful to have access to such a high quality for video. The free access to the knowledge is one of the most important thing in the world. And each of your Videos is a great treasure! Many Thanks for all these videos.

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I wish your my Professor

[@pragyapandey2517]

Same here... My wish too

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His haircut is so cute!

[@maddiedhiya9659]

randomgirl013 He's cute :)

[@Lily-si6uo]

o.O

[@kary2783neto]

@@maddiedhiya9659 Nope he is not cute in my opinion he looks like idk can't explain ;-;

[@LeweRG]

How helpful to have this video appear the day before my physiology exam, thanks crash course!

[@elliottedow6370]

Thank you for this great video. I have a kinesiology test tomorrow and this video is a great way to review for it! Please make more!

[@iman1922]

"Hormone hotline" I'm writing that on my test for sure.

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friking finals making me study this

[@snoopsxi]

I'm still here and I still love every video you've posted, THANK YOU

[@jeanneemmanuel9049]

You are so helpful. I love how you break this complex information down into such plain English. It's great! please keep them coming (:

[@omsafeya]

Thanks for the Arabic translation 💟 and you are a great teacher 😊👍

[@tahaahmed9722]

Nice name.

[@MetalPcAngel]

Spooky, scary skeletons ♫♪ send shivers down your spine♫♪ Shrieking skulls will shock your soul ♫♪ Seal your doom tonight ♫♪ Spooky, scary skeletons ♫♪ speak with such a screech ♫♪ You'll shake and shudder in surprise ♫♪ when you hear these zombies shriek ♫♪ We're so sorry, skeletons♫♪ You're so misunderstood ♫♪ You only want to socialize ♫♪ (but I don't think we should) 'Cause Spooky, scary skeletons ♫♪ shout startling, shrilly screams ♫♪ They'll sneak from their sarcophagus ♫♪ and just won't leave you be ♫♪ Spirits, supernatural ♫♪ are shy, what's all the fuss? ♫♪ But bags of bones seem so unsafe ♫♪ It's semi-serious! ♫♪ Spooky, scary skeletons ♫♪ are silly all the same ♫♪ They'll smile and scrabble slowly by ♫♪ and drive you so insane! ♫♪ Sticks and stones will break your bones ♫♪ They seldom let you snooze ♫♪ Spooky, scary skeletons ♫♪ will wake you with a BOO! ♫♪♫♪♫♪♫♪♫♪♫♪♫♪♫♪♫♪♫♪♫♪♫♪♫♪♫♪♫♪♫♪♫♪♫♪♫♪♫♪

[@Flaggirl1204]

MetalPcAngel i love this song it is awesome

[@abbiedaydreamr636]

YAY THE SKELLI SONG :D :D

[@ianpleake6682]

that table of contents is AWSOME I wish every video had that

[@rnj117]

oh my god ! this is on the syllabus for my exam in 9 hours time !!! Once again I say thank goodness for Crash Course, cannot express how many times this series has saved me !

[@patrickwilson3835]

It's sad when a Ph.D. professor cant explain something this easily!

[@mgs1398]

so is that why people say they aren't fat, they're 'big boned'?

[@amelia5665]

mgs1398 denial

[@melissalouis1680]

A!

[@PranamyaPradeep]

@@amelia5665 heavy bones are a thing- but they don't make you LOOK fat, they make your actual weight heavier than what you look to be

[@jaelipeterson8746]

These videos are so helpful! I should be paying my tuition to you! Thank you!

[@rachelcox8420]

These are amazing!! Seriously put everything into perspective when I'm studying for my anatomy exams!

[@katiexu7785]

0:17 skeleton's doing a t-pose.

[@kary2783neto]

Soo....???

[@raven2269]

Anyone catch the Harry Potter reference at 2:09

[@udayininamineni3210]

yup harry's 2nd year

[@rahulpillai2669]

Yeah

[@kehwie12]

yes, it made me so happy

[@pingreee9811]

This channel is so much better than my school sometimes, because you only use 9 to maybe 12 minutes to learn what you need, in school my teacher uses like an hour just go over 2 main topics which can be explained like this guy.