Introduction to Anatomy & Physiology: Crash Course A&P #1


Introduction to Anatomy & Physiology: Crash Course A&P #1

I’d like you to take a second and really
look at yourself. I don’t mean take stock of your life, which
really isn’t any of my business, but I mean just look at your body. Hold up a hand and wiggle it around. Take a sip of
water. Hold your breath. Sniff the air. These things are so simple for most of us
that we don’t give them a moment’s thought. But each one of those things is, oh, SO much
more complex than it feels. Every movement you make, every new day
that you live to see, is the result of a collection of systems working together to
function properly. In short, you, my friend, are a magnificent
beast. You are more convoluted and prolific and
polymorphously awesome than you probably even dare to think. For instance, did you know that, if they were all stretched out, your intestines would be about as long as a three story building is tall? Or that by the time you reach old age, you’ll
have produced enough saliva to fill more than one swimming pool? Or that you lose about two-thirds of a kilogram
every year in dead skin cells? And you will lose more than 50 kilograms of them in your lifetime?
Just tiny, dried-up pieces of you, drifting around your house, and settling on your bookshelves,
feeding entire colonies of dust mites. You’re your own little world. And I’m here to help you get to know the
body that you call a home, through the twin disciplines of anatomy – the study of the
structure and relationships between body parts, and physiology – the science of how those
parts come together to function, and keep that body alive. Anatomy is all about what your body is, physiology
is about what it does. And together, they comprise the science of us. It’s a complicated science – I’m not gonna
lie to you – and it draws on a lot of other disciplines, like chemistry and even physics.
And you’ll have to absorb a lot of new terms – lots of Latin, gobs of Greek. But this course isn’t just gonna be an inventory of your individual parts, or a diagram of how a
slice of pizza gives you energy. Because these disciplines are really about
why you’re alive right now, how you came to be alive, how disease harms you, and how
your body recovers from illness and injury. It’s about the big-picture things that we
either spend most of our time thinking about, or trying not to think about: death, and sex,
and eating, and sleeping, and even the act of thinking itself. They’re all processes that we can understand
through anatomy and physiology. If you pay attention, and if I do my job well
enough, you’ll come out of this course with a richer, more complete understanding not
only of how your body works, to produce everything from a handshake to a heart attacks, but I
think you’ll also start to see that you really are more than just the sum of your parts. We have come to understand the living body
by studying a lot of dead ones. And for a long time, we did this mostly in
secret. For centuries, the dissection of human bodies
was very taboo in many societies. And as a result, the study of anatomy has followed
a long, slow, and often creepy road. The 2nd century Greek physician Galen gleaned
what he could about the human form by performing vivisections on pigs. Da Vinci poked around dead bodies while sketching
his beautifully detailed anatomical drawings, until the pope made him stop. It wasn’t until the 17th and 18th centuries
that certified anatomists were allowed to perform tightly regulated human dissections
— and they were so popular that they were often public events, with admission fees,
attended by the likes of Michelangelo and Rembrandt The study of human anatomy became such a craze
in Europe that grave-robbing became a lucrative, if not legal, occupation … until 1832, when
Britain passed the Anatomy Act, which provided students with plentiful corpses, in the form
of executed murderers. Today, students of anatomy and physiology
still use educational cadavers to learn, in person and hands-on, what’s inside a human
body by dissecting them. And it’s totally legal. The cadavers are
volunteers — which is what people mean when they say they’re “donating their body
to science.” So what have all of these dead bodies shown
us? Well, one big idea we see over and over is
that the function of a cell or an organ or a whole organism always reflects its form. Blood flows in one direction through your
heart simply because its valves prevent it from flowing backward In the same way, your your bones are strong
and hard and this allows them to protect and support all your soft parts. The basic idea — that what a structure can
do depends on its specific form — is called the complementarity of structure and function. And it holds true through every level of your
body’s organization, from cell to tissue to system. And it begins with the smallest of the small:
atoms. Just like the chair you’re sitting on, you are
just a conglomeration of atoms — about 7 octillion of them, to be precise. Fortunately for both of us here, we’ve covered
the basics of chemistry that every incoming physiology student needs to know, in Crash
Course Chemistry. So I’ll be referring you there throughout the course, when it comes
to how things work at the atomic level. But the next level up from the chemistry of
atoms and molecules includes the smallest units of living things — cells. All cells have some basic functions in common,
but they also vary widely in size and shape, depending on their purpose. For example! One of the smallest cells in
your body is the red blood cell, which measures about 5 micrometers across. Now contrast that
with the single motor neuron that runs the length of your entire leg, from your big toe
to the bottom of your spine, about a meter from end to end.
Typically, cells group with similar cells to form the next level of organization: tissues,
like muscles, membranes and cavity linings, nervous, and connective tissues.
When two or more tissue types combine, they form organs — the heart, liver, lungs, skin
and etcetera that perform specific functions to keep the body running. Organs work together and combine to get things
done, forming organ systems. It’s how, like, the liver, stomach, and intestines of your
digestive system all unite to take that burrito from plate to pooper. And finally, all those previous levels combine
to form the highest level of organization — the body itself. Me and you and your dog — we’re all glorious
complete organisms, made from the precise organization of trillions of cells in nearly
constant activity. This ability of all living systems to maintain
stable, internal conditions no matter what changes are occurring outside the body is
called homeostasis, and it’s another major unifying theme in anatomy and physiology. Your survival is all about maintaining balance
— of both materials and energy. For example, you need the right amount of
blood, water, nutrients, and oxygen to create and disperse energy, as well as the perfect
body temperature, the right blood pressure, and efficient movement of waste through your
body, all that needs to stay balanced. And by your survival depending on it? I mean
that everyone’s ultimate cause of death is the extreme and irreversible loss of homeostasis. Organ failure, hypothermia, suffocation, starvation,
dehydration — they all lead to the same end, by throwing off your internal balances that
allow your body to keep processing energy. Take an extreme and sudden case — your arm
pops off. If nothing is done quickly to treat such a severe wound, you would bleed to death,
right? But … what does that really mean? What’s
gonna happen? How do I die? Well, that arterial wound, if left untreated,
will cause a drastic drop in blood pressure that, in turn, will prevent the delivery of
oxygen throughout the body. So the real result of such an injury — the
actual cause of death — is the loss of homeostasis. I mean, you can live a full and healthy life
without an arm. But you can’t live without blood pressure, because without blood, your
cells don’t get oxygen, and without oxygen, they can’t process energy, and you die. With so many connected parts needed to make
your life possible, you can see how we need a hyper-precise language to identify the parts
of your body and communicate what’s happening to them A doctor isn’t gonna recommend a patient for
surgery by telling the surgeon that the patient has an “achey belly.” They’re going to need to give a detailed
description — essentially, it’s like a verbal map So, over time, anatomy has developed its own
standardized set of directional terms that described where one body part is in relation
to another. Imagine a person standing in front of you
— this is what’s called the classic anatomical position — where the body is erect and facing
straight ahead, with arms at the sides and palms forward. Now imagine slicing that person into different
sections, or planes. Don’t imagine it too graphically though. The sagittal plane comes down vertically and
divides a body or organ in left and right parts. If you imagine a plane parallel to the sagittal
plane, but off to one side, that plane is the parasagittal. The coronal, or frontal plane splits everything
vertically into front and back. And the transverse, or horizontal plane divides
the body top and bottom. Look at that body again and you’ll notice
more divisions, like the difference between the axial and appendicular parts. Everything in line with the center of the
body — the head, neck, and trunk — are considered axial parts, while the arms and legs — or
appendages– are the appendicular parts that attach to the body’s axis. Everything at the front of your body is considered
anterior, or ventral, and everything in the back is posterior, or dorsal. So your eyes are anterior, and your butt is
posterior, but you’d also say that your breastbone is anterior to, or in front of, the spine,
and that the heart is posterior to, or behind the breastbone. Features toward the top of your body, like
your head, are considered superior, or cranial, while structures that are lower down are inferior,
or caudal. So the jaw is superior to the lungs because
it’s above them, while the pelvis is inferior to the stomach because it’s below it. And, there’s more: if you imagine that center
line running down the axis of a body, structures toward that midline are called medial, while
those farther away from the midline are lateral. So the arms are lateral to the heart, and
the heart is medial to the arms. Looking at the limbs — your appendicular
parts of your body — you’d call the areas closer to the center of the trunk proximal,
and those farther away distal. In anatomy-talk, your knee is proximal to
your ankle because it’s closer to the axial line, while a wrist is distal to the elbow
because it’s farther from the center. Okay, so pop quiz! I’m eating a club sandwich — I’m not, I
wish I was, but imagine I am. I’m so ravenous and distracted that I forget to take out that
little frilly toothpick at the top, and I end up swallowing it with a raft of turkey,
bacon, and toast. A fragment of the toothpick gets lodged somewhere
in here, and my doctor takes an x-ray, and says I need surgery. Using anatomical language, how would she direct
the surgeon to that tiny wooden stake inside of me? She might describe it as being “along the
medial line, posterior to the heart, but anterior to the vertebrae, inferior to the collarbone,
but superior to the stomach.” That would give the surgeon a pretty good
idea of where to look — in the esophagus, just above to the stomach! I warned you at
the beginning: Lots of terms! But all those terms might have just saved
my life. And it’s the end of your first lesson, and you’ve already started to talk
the talk. Today you learned that anatomy studies the
structure of body parts, while physiology describes how those parts come together to
function. We also talked about some of these disciplines’ central principles, including
the complementarity of structure and function, the hierarchy of organization, and how the
balance of materials and energy known as homeostasis is really what keeps you alive. And then we
wrapped it all up with a primer on directional terms, all held together with a toothpick. Thank you for watching, especially to our Subbable
subscribers, who make Crash Course available not just to themselves, but also everyone
else in the world. To find out how you can become a supporter, just go to This episode was written by Kathleen Yale,
edited by Blake de Pastino, and our consultant, is Dr. Brandon Jackson. Our director and editor
is Nicholas Jenkins, the script supervisor is Valerie Barr, the sound designer is Michael
Aranda, and the graphics team is Thought Café.

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100 thoughts on “Introduction to Anatomy & Physiology: Crash Course A&P #1”

  1. Solomon Richmond says:

    Wow if I was smart enough to understand all of what he said… I could be making a tone of money… But I has no clues as to what hes a'talking about. I'm to hill-billy for all this yall 😋😂

  2. Jaimee Price says:

    damn you're definitely way better than my lecturer! thank you, you're going to help me so damn much

  3. Deedra Taylor says:

    Slow down!!

  4. ABARTH ABARTH says:


  5. SullyHD says:

    i love this guy

  6. GalaxyGrl23 says:

    Anyone else watching this playlist for revision for exams? I know I am!

  7. Kimberly Almanzar says:

    This is really free education, and people rather watch game of thrones

  8. cypress mc says:

    THANK YOU SO MUCH FOR YOUR VIDEOS! They have changed my learning experience. It helps so much! THANK YOU!

  9. 11cassie29 says:

    So excited to learn from this!!!! I have been wanting to learn about anatomy recently!

  10. ImJustA Human says:

    I hate how my class instructor make it seem so serious when it could be this fun. Tbh I get more things into my head when i enjoy the topic beause its actually memorable.

  11. Chris Atha says:

    Pls help me

  12. Chris Atha says:


  13. kim sandoval says:

    Any chance you are willing to take on pharmacy courses next?

  14. Maria Holloway says:

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  15. Ricardo Ortiz says:

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  16. Anisah Abdullah says:

    I wish I had 7 octillion dollars…

  17. Andrew Parrish says:

    interesting points ,if anyone else wants to learn about anatomy of the entire human body try Laophiaa Cranial Blueprint (do a search on google ) ? Ive heard some awesome things about it and my neighbor got excellent success with it.

  18. Milan Goranovic says:

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  19. Ancient History says:

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  20. Markus Descheneaux says:

    play at 0.75 speed. your welcome.

  21. Sniper Fist says:

    lol was that mike tyson?lol

  22. thisgirlaira _ says:

    Thank you crash course for existing

  23. Ryan Robert Ventolero says:

    Any nursing student out there? HAHAHAHA

  24. Tony Tay says:

    From hand shakes to hearth attack LMAO

  25. valleyify says:

    I just wanna say thank you!! Your content is amazing and effective!

  26. browndd says:

    6:40 – I gotta admit that got a little chuckle out of me.

  27. Tania Spiegel says:

    Omg i got it! Had to watch it about 3 times because he talks super fast but i got it now! Thank you!

  28. Marcie Breelyn says:

    studying now before I enroll to nursing school and I'm seriously going to replay this playlist every chance I get,

  29. Kou-Lai Chang says:

    This is what every kid needs. Entertainment and Education.

  30. Jae Chung says:

    Great! Thank you so much!

  31. Anse Krekshi says:

    you r the best

  32. Kylekiller5826 0-0 says:

    I Have ADHD

  33. Abel Orain says:

    this is our lecture from the first day of class nursing

  34. Roselyn T says:

    Thank you!!!! 🙏🏾

  35. Davygreat says:

    Challenging myself to watch one of these each day for the rest of summer i’ll be back when I finish!

  36. BaBeBoBs Beauty & Fitness Consultancy says:

    I love this host. He is beautiful.

  37. Henry_Ballins says:

    Thanks crash course! Very interested in anatomy.

  38. Nightcore_ Ricktor says:

    This channel has always been the reason why I started loving subjects or topics that I never thought I'd love

  39. Sean John says:

    Good info but the guy talks too fast

  40. Le Nap says:

    5:57 tupac – changes is one of his songs
    Thats his tatoo and chain .

  41. Jenny Crenshaw says:

    Why is he better at lecturing this content in 11 minutes than my professor is with an hour and a half?

  42. Jose David 1507 says:

    This is just art in its pure state

  43. Åce The Åłien says:

    "Gobs of Greek."
    I'm stealing that.

  44. Black White says:

    I'm using this online crash course to assist me on becoming a fitness instructor. Thanks

  45. Crazy Best Friend Forever says:

    If all my classes were like this and at the end, for example you get like a 15min talk about this.
    That’s y im watching this right now…

  46. Kai Wen Deng says:

    typo at 9:03 caudal not caudial

  47. Shalyn Palmateer says:

    Anyone else get a warm fuzzy feeling hearing Hank call you a magnificent beast?

  48. Stuffed Panda says:

    I’m going to go through homeostasis in anatomy and physiology class… wish me luck

  49. Robert Rose says:



  50. Estefano Megerdichian says:

    Would the penis be appendicular or axial?

  51. Lo-Ruchama Hilaire says:

    Nursing students have entered the chat

  52. MadJester says:

    This is gonna help me through EMT, and Paramedic school

  53. chloé says:

    Thank you!!!

  54. Salman Ahmed says:

    I come from the future
    A year called…

  55. Sui says:

    my cat woke up at 6:42

  56. Ali Sa says:

    Batuhan Bensoy eline sağlık dostum:)

  57. sylvia njau says:

    He is my current most favorite person on Youtube. Saving me time

  58. eca 2001 says:

    I love this chanel

  59. Uzair Saeed says:

    6:41 This is what you came here for.

  60. Baconbread Productions says:

    I’m taking this class as a sophomore in highschool wish me luck

  61. SARAH Ba says:

    I likke youuu i likkee I LIKE YOUUU ♥️♥️♥️♥️♥️♥️♥️

  62. Michael Gossman says:

    Dude wtf. You record a woman dying at 6:41 and then just… move on? Jesus. Is she okay‽ Also, what is that cool spinny thing on your desk?

  63. kill frenzy says:

    6:39 – 6:55 LMAO

  64. Zetsuke4 says:

    this guy is extra

  65. Weissmargaux says:

    me at the start of the video

    oh, this was easy… not (the directional terms came in)

  66. Joseph Virtucio says:

    You’re so gifted. Wisiki kos imong ka bright 😂😂

  67. Dóra Rácz says:

    Suggestion: Crash Course Astrology

    Number of people interested

  68. Jasmine N says:

    Im 13 and i want to be ahead of the game and his youtube videos are really educational🙃Free education😂🙃

  69. Jean Ryee says:

    I am just a typical teenager who took nursing bcs of my parents, tho I don't even know if i would graduate or what. Thanks for this video bcs now i know what will be the death of me. Wish me luck.

  70. Taylor Watson says:

    Taking notes for med school 📝

  71. Richard Gledhill says:

    This guy need to slow down and not talk so fast, for some people in my course it makes them not take on any of the information or very little

  72. Kandi Undi says:

    0:50 got deep really quick

  73. mycatisromeo says:

    My knowledge of anatomy and physiology is inferior to this guy's. Pun intended.

  74. mycatisromeo says:

    Funny how medical professionals along with any other professional in their profession, come up with fancy terms to try to make them seem special. Here's a term from my field of study; business; the allocation of resources. The world is a business. Consumers use up resources. And now I cross over two Fields of study. Humans are like a parasite. They consume resources on planet Earth making it inhospitable for other life. Any questions? The state of the economy, and the homeostasis of Earth are in peril. How to fix it? Consume less. Don't spread your genetic material.

  75. Precious Thandi says:

    I love your person

  76. Amiriam Watson says:

    Taking this class in 2 weeks any advice people please 😭😭

  77. Fashionably Me says:

    Thanks for the lesson I needed this

  78. Flyawayandbe free says:

    Will this series help with a Uni degree. Or is it too basic?


    u making the whole library in holland just turn heads on my lap top,

  80. ramesh naidu says:

    Telugu lo ledha

  81. Hussein Ali says:

    Thank u crash course team

  82. josh stout says:

    This guy is trash and probably raped someone

  83. Clark TKD says:

    Im starting physiotherapy bachelor in 3 weeks.
    I'm so happy with this videos, they will help me a lot. In fact, because I laugh, and that's my best way of learning. With my ADHD makes it really boring just sit down with an open book. Everything I learn much better in this way. Thanks a lot!

  84. Nicole Crockett says:

    I took anatomy last year and I learned nothing because my teacher sucked. Now I'm going to spend my free time watching these videos and taking notes to learn anatomy so I can be a successful nurse. So thank you.

  85. ErenTheBombJaeger says:

    Almost everyone here is in college and here I am a simple high school senior in Anatomy & Physiology class XD

  86. Y G says:

    I'm still in middle school but I want to be a doctor. This video helps a lot and it's so fun. Thank you for this video!!!

  87. Joe Pineapples says:

    My teachers were like useless scarecrows., this one is not. 🙂

  88. Omar Martinez says:


  89. Saphira Peridot says:

    I'm only 13 and this really interests me……. Is that weird?

  90. Morgan Montgomery says:

    Danggg thanks for this

  91. hyuna seon says:

    If there's one thing bad about crash course is that it made me want to self study with Hank and just skip school XD iloveyou!!!

  92. William Weaver says:

    What she said ⤵️⤵️

  93. Zomberz -04 says:

    I’m 15, and I’m reading anatomy flash cards and watching anatomy and physiology videos. Is that weird?

  94. Neurolang Centre says:

    why do you speak sooooooo fast?

  95. Majestically Savage says:

    I'm here 'cause my friend who is taking nursing wants help in understanding this so I had to look for videos she could watch😅

  96. Raven Kunz says:

    i’m taking this class junior year with chem and i’m gonna kms

  97. Zach says:

    5:56 Is that supposed to be Tupac? Lmao

  98. Alyssa Kwiecinski says:

    You’re helping me get through college. Thank yiu

  99. Robin Sanchez says:

    I'm glad my A&P professor recommended these videos. They've helped me so much is my first term of LPN school. I recommend them to other nursing students. It's a great tool and resource.

  100. Krysty Gomez says:

    So I decided self torture of taking this class although I don't care for being a nurse or doctor. 🙂

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