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 your hand 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 and short you my friend are a magnificent beast you are more convoluted and prolific and polymorphously awesome than you probably even dare to think Vern’s dance 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 she’ll 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 that world 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 signs 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 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 and 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 stuff that we either spend most of our time thinking about or try not to think about death and sex and eating and sleeping and even the act of thinking itself all processes that we can understand through anatomy and physiology if you pay attention and if I do my job well enough you come out of this course with a richer more complete understanding not only of how your body works everything from handshakes to heart attacks and I think you’ll also start to see that you really are more than just the sum of your parts [Music] we’ve 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 and slow and often creepy Road the 2nd century Greek physician Galen gleaned what he could about the human form by performing vivisections on pigs DaVinci poked around in 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 anatomist s– 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 the human body by dissecting them and it’s totally legal the cadavers are volunteers which is what people mean when they say that they’re donating their body to science so what of all these dead bodies shown us well one big idea that we see over and over again is that the function of a cell organ or a whole organism always reflects its form blood flows in one direction through your heart simply because it’s valves prevent it from flowing backward in the same way 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 all begins with the smallest of the small atoms just like the chair you’re sitting on you are just a conglomeration of atoms about seven 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 these smallest units of living things cells all cells have some basic 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 five 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 etc that performs 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 and stomach and intestines of your digestive system all unite to take that burrito from Lake de PUE per 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 and nearly constant activity this ability of olivine 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 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 the 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 I thought there isn’t gonna recommend the patient for surgery by telling the surgeon that the patient has an achy belly they’re gonna need to give a detailed description essentially it’s like a verbal map so overtime 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 is 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 slits 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 even 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 a particular parts that attach to the body’s axis everything in 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 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 lowered 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 a centerline running down the axis of a body structures toward that midline are called medial while those farther away from the midline are lateral of 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 the little frilly toothpick at the top and I end up swallowing it with a raft of turkey bacon and toast a fragment of that 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 vertebra 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 the stomach I warned you at the beginning a lot of terms but all those terms might just save my life an a it’s the end of your first lesson and you’ve already started to talk to talk today you learned that anatomy studies the structure of body parts well 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 cafe you [Music]


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

  3. 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.

  4. hey ,if anyone else trying to find out help human anatomy try Laophiaa Cranial Blueprint (search on google ) ? Ive heard some extraordinary things about it and my friend got cool success with it.

  5. hey ,if anyone else wants to learn about meaning of human anatomy and physiology try Laophiaa Cranial Blueprint (search on google ) ? Ive heard some super things about it and my neighbor got cool results with it.

  6. 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.

  7. hi everyone ,if anyone else needs to find out about anatomy the human body try Laophiaa Cranial Blueprint (just google it ) ? Ive heard some unbelievable things about it and my mate got amazing success with it.

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

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

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

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

  13. 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…

  14. 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?

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

  16. 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.

  17. 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

  18. 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.

  19. 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!

  20. 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.

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

  22. 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!!!

  23. 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!!!

  24. 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😅

  25. 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.

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