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!

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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[youtubequeen]

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)

[eileenbvanmerk]

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.

[sarahnaji]

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

[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

[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. :)

[ericgonzalezmusic]

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

[mackenziepark]

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

[rozhinhamidizareh]

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!

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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.

[kaylaarmani]

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

[julie]

Who else is watching this because of their teacher in quarantine

[jordanwoods]

You should do a video on Intramemberous and Endochandral Ossification!

[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

[corbinmarion]

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

[kimberleysinclair]

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!

[christofferenfors]

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!

[chrisbailey]

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

[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!

[joanmubea]

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

[LilDaz]

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