Reproductive System, Part 4 - Pregnancy & Development: Crash Course Anatomy & Physiology #43

We've reached the grand finale of our four-part series on human reproduction: BABIES! Today Hank walks you through the stages of pregnancy, beginning with how a zygote develops into blastomeres to a morula to a blastocyst, and finally to an embryo and a fetus. He also explains some of the amazing anatomical changes that take place in the mother and the hormonal sequence of events that lead to labor.
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: How Did You Get Here? 00:00
Cleavage Stage: Zygote, Blastomeres, Morula, Blastocyst1:34
Implantation 3:08
The Placenta 4:50
Embryonic Stage 5:07
Female Anatomical Changes During Pregnancy 5:30
Hormonal Sequences Leading to Labor 7:12
Stages of Labor: Dilation, Expulsion, Placental Delivery 8:35
Review 9:34
***
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[@crashcourse]

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

[@user-yb3zs6lf3l]

CrashCourse AMAZING MY FINAL IS TOMORROW THIS COULD NOT HAVE BEEN BETTER TIMING

[@annalloyd4418]

The way that Hank Green and John Green are the back bone of the American public school system is UNREAL. Thank you, from the bottom of my heart. The impact you and your brother have made on the world is unreal.

[@stephimarie317]

These videos are LIFE SAVERS for finals

[@asparagusman4481]

me right now lol

[@PoisonJuke1]

Haha, so true, i have my exam next week

[@mmalph]

Same! haha

[@404bidden]

Have my final tomorrow LMAO

[@kassemwahid163]

Same

[@EntrE01]

what do you mean you don't know me hank?! We've shared all these great times together! Like, remember when I watched all your videos? Hell that was pretty sweet now wasn't it. Don't you say you don't know me, it hurts.

[@zoryfahringer210]

is it sad that this channel has taught me more than my science teacher had? 😂

[@alyssamsipe9123]

o be honest, yes. There's so much shame on sex and reproduction in school.

[@EvilNeonETC]

i had health class, but these videos are much better at explaining things, even though my teacher was highly entertaining.

[@joergsprachsprechen8214]

+EvilNeon * entertaining *

[@EvilNeonETC]

+Enzo Ciarlini no puns, he literally was a great teacher.

[@damonsalvatore269]

Zory Fahringer why do u think I'm here? LOL 😂

[@lizzysilvers2119]

Its nearly 1am on the day of my A+P 2 final... It's a 4-year-old video and still reviewed everything I needed to review for this concept... I'm a college student. Crash Course has always been a blessing for finals!!!!

[@macitotom]

You Know,I never find what he's saying in my textbook....but I still watch it anyway, because it's THAT GOOD I'm a 3rd year medical student,and still watch his videos because Everytime I do,I learn something new....he... along ninja science nerd....made me feel that I actually understand medicine somehow.... Good luck with your exams by the way 👍👍

[@strivingwithsteph1649]

"Learn how you're gonna put the little thing through college" 😂

[@-._.-KRiS-._.-]

Children aren't going to need college in 18 years from now with all this free education online.

[@saluthigh1676]

@@-._.-KRiS-._.- They will still need certificate and do you think online learning is good enough. It would be if we all follow some good lecturers but when my lect try to make a vid LOL

[@ThatAnnoyingBird]

0:00 "Who are ya callin' Pinhead?"

[@mo-te6uy]

I'm Dirty Dan >:^0

[@neilpateldpt]

lmao

[@nathanw8622]

+Mount MC what is a "dirty dan"?

[@nathanw8622]

o! o git it!

[@bethyboop1496]

no i'm dirty dan

[@realmoz3057]

Mothers are amazing! They have to go through temporary pain for a lifetime of happiness. Thank you mothers!

[@GingeredHonii]

sometimes i feel bad for my mommy ;w;, she had to go through the pain with me for 10 months.

[@agirlwithdreams15]

TheCraftingCookie lol at you thinking motherhood is happiness

[@summerbella-yi4cw]

TheCraftingCookie I wish I still had mines... :(

[@Paprikaah]

Amber Nougat 9 and a half

[@-._.-KRiS-._.-]

It's not exactly temporary pain. Being a parent offers a lot of wear-and-tear on the body, especially when the child is in infancy. There's a lot of isometric-like exercise going on with constantly lifting and carrying someone that goes from ~5-9lbs to ~12-16lbs in just six months.

[@furzekake1]

All this pain and tears from all mothers in the world has created us. Thanks to all mommys in the world! With your altruistic behaviour we can live.

[@wehavnoidea]

+Nathan Pattison Some women aren't ready to have babies. No reason to shame them for not being ready to go through this long, difficult process.

[@mightyNosewings]

+Nathan Pattison The human population is going to hit 9 billion this century (assuming all goes well, and hopefully it will peak there).

[@spindash64]

+Emily Ericson I'm not shaming them, I'm shaming us for telling them it's ok to murder another human being just because that human being can't speak for his or herself. I feel anger, yes, but I don't hate anyone. A person's a person, no matter how small

[@wehavnoidea]

+spindash64 We have never been told that it's okay. Women are mocked, shamed, and humiliated for simply not being at a point in their life where they are able to give birth to a baby. And by that logic, the millions of eggs inside my body right now are already people. A zygote is a zygote, not a person. Of course it's not an easy decision, but it's a decision that women should have the right to make.

[@wehavnoidea]

+Nathan Pattison I'm sorry, but would you, as a man, be willing to put your life on hold for nine months for a child that you don't even want? To experience all of the horrible symptoms told about in the above video, to have to switch your entire life around? No. You wouldn't. What you have to say about what a woman does with her body does not matter, because you are not a woman. Just like you can't force a person to donate blood or organs against their will, you most certainly can't force a woman to go through this life altering experience because you believe a fertilized egg is a person.

[@flynnkay]

This youtube channel is amazing. it teaches children on youtube (which is where ALL kids are) about science and space etc. which is the real and good interesting stuff in life!

[@zachruhl6008]

+GreenShot They also have to more kiddish version.

[@zachruhl6008]

***** Well they never had a reason too.

[@TheReaper569]

Im not s child but i watch it all. My county lacks reproduction and sex ed because.. Religion.

[@zachruhl6008]

Hakan Karaağaç what country do you come from?

[@TheReaper569]

Turkey. Formally secular but going more and more religious conservative by the leadership. Im the last generation that finished highschool with reproduction lessons in humans in biology.

[@AlexTheMary]

I shall save this video so that everytime I have baby fever I can rewatch this and be reminded as to why that is a bad idea.

[@alexisreyes4179]

Right exactly

[@ItsMzPhoenix]

?

[@bravanator551]

Girl I got it bad too, so I just watch as many scary delivery videos as possible & pay close attention to how evil the little things can potentially be at 3 & that helps me remember to wait till I have a degree before becoming a mother.

[@gremistaoloco8881]

Of course you shall save it, you are American. and what Americans know best then put a baby in the world every nine months???

[@bravanator551]

Gremistao Loco actually America has a slower repopulation rate than many other countries. Not sure where you got the idea from that we pop out babies on a regular basis but that’s really not how it is here.

[@taylorbarnett1199]

I have had 2 vaginal births can’t wait for my next little buddy. I love being a mom

[@zerogravity245]

"You don't make a car by carving it from a single chunk of metal..." I dunno... Apple might...

[@electrosthefella]

*CHALLENGE ACCEPTED*

[@chillsahoy2640]

It sounds like the fetus and the mother are having a pleasant biochemical conversation but consider this: the fetus can make a special kind of hemoglobin that has a higher affinity for oxygen than adult hemoglobin, which means that the fetus is pretty much wrenching oxygen away from the mother's hemoglobin. Still, the reason it evolved is because it works. Go biology!

[@yasminakatebi9265]

Im happy,finally hearing a man to say:i really don't know how emotionally ladies bare someone,a whole new person growing in them. Yup,happy to hear someone respecting women.. With all respect to hank green for the sake of the respect he gave females with this very sentence.

[@abdulaleem712]

hank is so proud of us for growing up. me too hank, me too.

[@Dymphna1990]

I think it would be cool to have a crash course "What to expect" series. Lots of pregnancy sites have week by week calendars where they tell you what's up with baby. But Crash Course is so fun, I think it would be cool to see what they had to say about the 40 weeks of Pregnancy!

[@michellesasser2897]

Happy Mother's Day! And good luck with everyone on their AP biology exam tomorrow!!

[@arushramteke730]

"After that, all you have to worry about is how to put the little thing through college" 😂😂😂😂😂😂😂

[@thoryne]

0:21 was that Shia LaBeouf clapping? :D

[@crashcourse]

+Thoryne Sure was! Good catch :D -Nicole

[@dbartholemewfox]

+Thoryne Weird that they didn't animate Orson Wells as Citizen Kane clapping...

[@Redlin5]

+Thoryne I saw it too. :)

[@kAshley92]

+Thoryne I literally laughed out loud when I saw the cartoon clapping because I had read your comment beforehand. That was a good one.

[@thoryne]

+kAshley92 I made someone laugh? Good, it means that my job here is done :P Also... I'm watching the original Shia video over and over again, where this clapping was taken from >.> :D

[@yolandasandoval1352]

The reproductive episodes have been hilarious, and of course informative :) Thanks for all your great videos, you have definitely helped me out a lot in my anatomy class! Final is tomorrow!

[@KJHutchinsMusic]

Please make a comprehensive Crash Course Sex Ed. Lots of people really need it.

[@StevenEveral]

And that is literally how all of us got here.

[@sailingthesouls]

These videos are extremely helpful! He keeps them interesting and explains complex topics so any level can understand them!

[@TheJoyannika]

I'm 7 years old but I want to be a good doctor

[@Scerttle]

If you're already watching stuff like this, you're well on track. Keep it up.

[@lucianalove9492]

Omg, kid you can spell better than most adults, it's a lot of work to be a doctor, but my advice is to study and never give up! Good luck!

[@deardarlingdollies5851]

My advice is to start looking at chemistry videos now and get good at chemistry as well. You're off to a good start. Good luck!

[@blugaledoh2669]

Luciana Love Your comment just make me feel sad, is it true.

[@victoriaamabile7575]

Keep it up!! You´ll have a long journey but it will be worth it!

[@rjfaber1991]

Or, in Gaius Julius Caesar's case: "It involves a system of hormonal signals that, as sophisticated as they are, get interpreted by the very earliest human cells into two simple instructions: Divide, and Conquer."

[@blackmesa232323]

That applies more to cancer than fetuses.

[@MakeMeThinkAgain]

+Robert Faber I thought you were headed toward Caesarean Section. It would be interesting to do another episode on all the things that can go wrong during this process.

[@venkatramancv812]

Thank you so much. Your human reproduction videos are excellent. I am glad you don't feel awkward talking about it because your videos really helped me to understand it.

[@vaishnaviramakrishna265]

That's what I need for my finals!! thanks 😘....love this channel!! keep it up!!

[@merryissac8265]

Great teaching. I never felt more interested. Thank you.

[@BunnyFett]

I still love how he credits everyone at the end of each video.

[@alliegriffin1274]

I was introduced to your videos last semester in A&P1 and have watched you since! But this semester I was introduced to your history lessons AND I saw you in some art assignment videos! You've changed a lot in the years! Good for you, can't wait to see what you teach next ;)

[@car-azy_tm]

Finally. An answer to the age old question: How is babby formed?

[@takingitright]

how girl get pragnant?

[@shar371]

+Sugoi Hands sex

[@siongy6726]

Is she Bregnant

[@inflexibleprick1709]

Be getting pregante

[@ScareSans]

6 months plus 2 weeks...... PREGANANANT!?!?!?

[@carno0729]

I watch the CC video before I watch my professor's lecture videos. They are THAT GOOD! Thank you for helping me ace A&P1&2!!!

[@edwardtempelii162]

Thank you so much Crash Course! The way you explain things help me understand what the textbook is trying to explain. I have enjoyed learning A&P very much. Sometimes this course is down right tough, confusing, and hard to understand. Thank you for helping me make my light build came on! Those realization moments have happened many times Crash Course. I watch the videos after I have read the textbook because the host talks extremely quick and uses big words that are going to be used to explain steps in physiological processes. I guess that's why they called A&P. My thanks and best wishes go out to you.

[@regitarahmamaharatri3410]

It helps me so much to understand my subject class, thank you CC!

[@liliumjade]

This is what I'm gonna show my son when he asks me where babies come from.

[@TheNoa36]

I laughed out loud when he said the baby will combine aleles with someone

[@raiden6318]

You've help me pass my A&P Essential class. Thank you. 😇

[@M_Chen333]

Hank must've gone through a lot of... LABOR!!!!! making this episode!!! HA HA HA HA :) :) :) :)

[@huckleberryhuckle9934]

M. Chen very funny 😂

[@sarahkuder5018]

Lol

[@leanejoubert8517]

Me writing a test on embryology: I bet this video will help Hank: So we won't focus on that

[@Alex-uf3lh]

I'm watching this while on Mother's Day

[@alyssamsipe9123]

I'm currently in Child Development right now, so all this solidifies what I've learned already and then some

[@shade7405]

this is sooo helpful! I love this channel! I recommend it to all my classmates

[@Champion_Trainer]

Thank you for these videos; what a time-saver!

[@someone-ub7hg]

Thanks a lot. Your videos are amazing and interesting. I watch them after studying each system in my textbook. They are more beneficial than the silent pictures in the book. Thank you!

[@rowbinegamergirl]

thank you for all the videos you make it really helps while studying for biology

[@chiralhome]

i like how Thought Cafe did the illustrations. . . . They described it well enough and still kept it tasteful and entertaining... less is sometimes more

[@loisbaker6922]

these videos have been sooo helpful because i have a science test on this subject and i didn’t know how to revise and then i found this and it was sooo helpful thank you

[@sallycrow1494]

Starting to feel prepped for my exam, this has helped a lot!

[@reymystorioable]

Your videos should get a lot more of attention then they do. Keep up the good work!

[@K.S.Khunkhao]

Superbly done! *Slow clap*

[@toniaa-y3559]

Ok seriously Hanks first minute before the theme song almost always cracks me up

[@graceolowu699]

I love how you make fun and easy to comprehend.

[@zarlsx2216]

Thanks for all the videos! Youre getting me through school

[@rowanreads1118]

i have a science test tomorrow, thanks so much dude you’re a lifesaver!

[@ignatiusjoseph1676]

THESE GUYS DESERVE TO BE MILLIONAIRES MABY MORE THEY HELPED ME SO MUCH

[@georgetello2203]

THAT WAS AWESOME! I NEVER STOP LEARNING!

[@nandhan6637]

Great explanation.. Thank you so much

[@maricis96]

I love your content. It has been a great help with my A & P courses.

[@peternouwen]

Excellent episode, especially the last remark after the summary…

[@sumitmohapatra4924]

Thank u sir and your team... its a great help in studying the chapter

[@chrisnunez1947]

Thank you for making this :)

[@TheJoyannika]

I appreciate your work on this 😇

[@naumanlal1548]

I watched ur videos while preparing for my medical college admission test and now when I finally got admission (thank God) I’m still watching ur videos. ✌🏻😍

[@ibitsola]

Thank you CrashCourse

[@laurellion3567]

I took my A&P2 final today and I miss Hank already.

[@rita_fcortez]

I have an exam today about that! that helped me A LOT!

[@RNH2O]

Hank is awesome 👏🏼

[@tanyamedrano184]

Yayyy WE'RE DONE WITH AP2 CONGRATULATION EVERYONE YALL DID IT WOOT WOOT

[@victorious4701]

You are Gods! Seriously your channel thought me more than 10 encyclopedias worth of information! And you deliver the most important stuff if the subjects of the videos so than anyone can understand. No matter of they're a nerd or a regular! Thanks for keeping learning fun and awesome for me and everybody else! And, as always, DFTBA!

[@victorious4701]

And I think that this channel is waaaaay more underrated than it should be! I mean you guys deserve to be shown to EVERY school there is and yet you have only what, 7mil?! I'm so grateful that I found this channel and that I was able to share it to more than 100 people. Keep doing your best!

[@tinkerelsa2882]

Let me tell u man ! U r simply awsome ...and ur videos ...i just got addicted to them 😄

[@chiralhome]

you're the best hank

[@Canadianezhik]

awesome course - thank you

[@melissahall7009]

Thank you so much for these videos! I will donate soon!

[@yuta2349]

Well explained !

[@srehaviswanathan1434]

I love my mum a whole lot more than I already did now :)

[@erikpinochet7655]

Loving the episode! Not to be a pain in the ass, some things are wrong: the two cell stage is reached approximately 30 hours after fetilization. four-cell stage at 40 hours, and 12 to 16-cell stage is reached after 3 days and it is this 16-cell stage that is called morula. Besides this, good job guys!

[@chiangui24]

that animation was amazing

[@annidee]

Isn't the head of a pin the non-pointy side? As opposed to the point of a pin? 😐

[@Plystire]

+anni dee if you zoom in far enough -- they're *all* non-pointy sides. ;)

[@Quotenbrtchen]

+Mohammed Samiwala Not quite, electron orbitals sometimes have freaky shapes that are not round at all.

[@gato815]

+Mohammed Samiwala You can't zoom in into the molecular level.

[@RanaKamikaze]

+anni dee well you were also that size

[@rynsawyer4185]

+anni dee that's what I thought...

[@ProggresiveArt]

Next week i have an oral exam on gynecology and obstetrics, and i need this info, its not like i dont know this, but when i see these vids i can memorize the facts a lot better and longer so... . Thank you for making the material so vivid and easy :)

[@-._.-KRiS-._.-]

Please don't induce your patients unnecessarily, especially if it's just because you want to deliver the baby a week early because you're going on vacation the week it's supposed to be born. That is all I ask of a future obstetrician.

[@natalia5189]

me encantó, lo amé

[@reemamer6946]

Wow! Thank you 💛

[@saurabh2693]

really hank, great. you are the best

[@cindyoneill5800]

AWESOME!!

[@sagirkhankhan6099]

These videos are life

[@annweshamandal875]

great explanation...

[@coffincoffee1]

These videos have been very helpful for me! However, maybe you can add to it by doing something about preventative birth control and contraception? Maybe about the different options available and how to prevent unwanted pregnancies as well as std prevention and how it works? I think that would really complete the sex education you have going on here.

[@robm6726]

almost done, just have A and P 2 lab for the fall semester, taking lecture over the summer lol.

[@island-wind]

That angler fish on your desk,where are it's eyes? :3

[@GingeredHonii]

your profile picture is messing with me

[@benitapitt1199]

i thought it was moving haha

[@TimmyIAm]

Alex Friesen its your mind making it look like its moving threw your eyes

[@987werther]

New Crash course video!!!

[@mohamad.hamdihamdi9475]

You are just a legend

[@kanchanaashok9094]

i like the way he teaches. and i wish he was my bio teacher.

[@kanchanaashok9094]

very true

[@umkalthoomahmadzarouq6464]

tthis is soo good thank you

[@user-yb3zs6lf3l]

please make a video series dedicated to microbiology !!!!

[@MuhammadRafy]

1:31 Divide and Rule

[@shakilaasad7368]

BEST VIDEO

[@parvinkazi7962]

Very Helpfull

[@spr35441]

As a geology and geography major, all of this biology talk kinda freaks me out

[@SASRosco03]

Awesome Video! Please make a math course.