Reproductive System, Part 3 - Sex & Fertilization: Crash Course Anatomy & Physiology #42

After weeks of discussion of human reproduction, today we arrive at the main event: THE SEX. Hank explains the four phases of the human sexual response, how fertilization happens, and how different contraceptive methods work.
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
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Chapters:
Introduction 00:00
Four Phases of Human Sexual Response Cycles 0:53
Fertilization 3:01
Contraceptive Methods 6:59
Review 8:58
***
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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

[@charlidameli3200]

Pis my sexy plis aaaaaaaa

[@Starlight2097]

we're gonna keep as sfw as possible *inserts loud sex noises*

[@ivanhps5498]

rolled my eyes at that

[@ronaldojones8370]

Universal LITERALLY

[@FlissHearts]

I know. I died.

[@icycupoffreshlemonade3194]

Wats sfw

[@starling3029]

"We'll do this as SFW as possible." 1 minute in: "*very suggestively moving people*"

[@SuneOli4]

It's actually pretty amazing how much can go wrong before an egg is even fertilized, and yet here we all are!

[@zachgaskins3731]

+sune olivier Hence the male's biological tactics, even with just one partner, is "shotgun alpha strike".

[@dickiewongtk]

My biology teacher used to say each of us is a mini miracle.

[@luismendoza1972]

now think about how many more us aren't here tho..

[@dankmemes5303]

@@luismendoza1972 deep...

[@hydrogendiamond5830]

It also adds another poetic layer when you remember that are bodies are made of the remains of exploded stars. (Look up Crash Course Astronomy for that info).

[@Lewlsquish]

You’re telling me that I wasn’t the sperm that won the race? I merely entered because the fastest sperms broke down the walls for me to get in? No wonder why I’m a failure

[@wikipediawikipedia5626]

Hahaha

[@yansakuya1]

@@ahmed7874 He is neither smart nor cheated the system, as that is how the system works for everyone, and so the system is working as intended, he is not smart either because their was countless other rushing behind doing the same if he did not make it. So if anything he is the lucky survivor that made it pass the near countless obstacle in the way.

[@mooali3985]

Haigo Li shut up loser

[@abelaguilar-acosta8691]

Lewis Quish In a way you're less of a failure, and more of a diamond in the rough that was found during an earthquake. So you're pretty lucky. 😊

[@travisk5589]

@@yansakuya1 You are such a buzz kill

[@yaqarianfanashira]

"the sex" *saxophone music * 😂😂😂😂😂😂😂😂😂😂😂😂😂😂😂😂😂

[@WhiteRaven621]

That was hysterical everytime

[@toniaa-y3559]

THIS WAS THE COMMENTARY I WAS LOOKING FOR😂😂😂😂

[@sksksksk2911]

LMAO 🤣

[@daniellowe5420]

Hee haw

[@procrastinator99]

OH GOD, THAT FLIGHT OF THE VALKEIRIE!!! LMAO!! Trying to be mature and absorb the information, but holy ........ that was hilarious.

[@angelcollina]

+procrastinator99 I loved that too!

[@sakimaos.3470]

I KNOW RIGHT?!?!? I TRIED MAN, BUT I FAILED AS SOON AS I HEARD IT. XD

[@thomasgabby6214]

I bet the animators couldn't keep a straight face when making the video assets or animating them.

[@MSadamgasm]

i have already learnt all this 2 years ago, but idk, its just really amusing to watch Hank talk about The Sex XD

[@avaakacrow4182]

Are you 12

[@MSadamgasm]

+Your Consciousness really? is this the best u could do? haha try harder.

[@danielgwillim8220]

+MSadamgasm I dunno man, things like "The Sex XD" don't ooze maturity

[@MSadamgasm]

+Daniel Gwillim i was just repeating what Hank said xD but it is amusing cuz its not everyday u hear Hank talk about The Sex.

[@chickenmonger123]

+Daniel Gwillim Interesting. I guess it has always been the way one increases fake maturity. That is bashing another for finding something funny. That ever present human trait of elevating yourself above another by judgment, and hoping others do the same.

[@LynneSkysong]

I love CrashCourse's take on explaining sex. If only this was around when I was in school. Oh well, it is now! My one constructive criticism is that I would have liked to see a plug for Sexplanations in the beginning when Hank talked about all the things they WOULDN'T be taking about. Other than that, excellent job!

[@Bladavia]

Were the moans really necessary ?! oO

[@buttsbutts7858]

Yes

[@veganbackpacking-8559]

Someone is afraid of people thinking he's watching porn while also listening to CrashCourse hehe

[@changolord93]

yes its science

[@darnellbynoe8328]

lol it was hillarious

[@eduardorescalla5933]

YES YES YES YES... YES!!!!

[@jaredjones1752]

6:33 lol I love the 3 sperm sitting right outside the egg, like they're jealously thinking: "Damnit, that should be US in there!!!!" 😂

[@FiniteAtticus]

LOL @ 3:59 Flight of the Valkyries should have been played through the whole video, that would have been hilarious! ...though people probably would have taken it less seriously.

[@gabrielmentasti3115]

Made me chuckle. Great music for the context

[@TheNoa36]

+Gabriel Mentasti I laughed out loud when I heard it, the first thing I thought was "INVADE POLAND!!!"

[@enchantedeyes3137]

+Finite Atticus I LOLed too. It reminded me of that scene in "Apocalyse Now" as the helicopters attack a village.

[@jestonylumabi3561]

+Finite Atticus It makes me laugh. First thing I thought is: "INVADE EVERYTHING"

[@Abominatrix650]

And your comment reminds me of when Dr Manhattan fought in Vietnam in Watchmen, Ferdie. Coincidentally, he nearly always had his sex organs out the entire time

[@rynsawyer4185]

I had no idea fertilization was so complicated. This is actually quite interesting once you get past the awkwardness.

[@anusha2353]

Ahahaha, the music at 4:06, love this series, definitely helping me prepare for the exam! Thanks!

[@natanya5394]

Thank you so much for your videos! They have helped me pass biology throughout school!

[@sarahwells4610]

It'd be awesome if CC could do a video on how the different types of twins are formed as well as how chimeras happen. :D

[@obailon4995]

Thanks!! im now ready for my practical exam! i've been watching this channel since last year from my psychology class to my now A&P classes. A big help you are!

[@K.S.Khunkhao]

Very informative. Reminds me of the miracle of life. Thanks Hank and CC!

[@abbierwl]

hank rocks... such a great series of videos... thanks for getting me through A&P

[@syddlinden8966]

Again, thank you for talking about the science of sex. There are any number of great sex ed/sexual behavior channels, but none that I've found, Sexplanations included, that give any indepth information as to what's happening biologically. And I think it's of utmost importance for us as biological beings to know and understand this material even before getting into the behavioral and physiological parts of the equation. Don't get me wrong, Sexplanations is great, but I regularly find myself saying, "yeah, but you didn't actually tell me anything. Certainly not anything about the physiology of (sexy whatever topic).” So, yes, thank you CrashCourse for getting to the real nitty gritty of what we do in the bedroom in a way that no one else is talking about. :D

[@exceldivine]

Idea for a birthday cake: Congratulations on winning the race!

[@stephanies3262]

this was the most entertaining crash course video

[@riverbedassie5204]

love this channel your voice is so soothing

[@riko2965]

best youtube channel everrrrrrrr! and i really mean it, its the best! Thank you! i can litterally pay for this channel

[@blu8993]

Hank left me intrigued . Now I want more 😊

[@Ettyofacts]

boy am i glad to find that crash course has a video on emrbryology

[@potato3salad]

Thank you for all that information, i was wondering how emergency contraception works in that phase though. How does the morning after pill work?

[@crashcourse]

+Dan Mac The morning after pill works by delaying ovulation, so that the sperm and egg don't get a chance to meet. It can also interfere with a fertilized egg's ability to attach to the uterine lining, but it's most effective if ovulation hasn't happened yet and it can delay it. (It can also make the menstrual cycle a little wonky for this reason.) -Nicole

[@potato3salad]

+CrashCourse thank you so much for this extra information

[@potato3salad]

+CrashCourse if only this was explained clearly in school or at least in the pill's inserts. Crash course love forever

[@millyess247]

we watched this in science class! great video! !! xx

[@chibiprussia5574]

3:57 LOL THAT SONG

[@allenpeppers2576]

He may talk fast but he keeps your attention!

[@alannahhurley386]

Gosh! I really need to give sperm cells more credit. Sure the female reproductive system does most of the work but the sperm cells do have to woe the heart of a egg (metaphorically speaking) and that's almost as hard as wooing the woman.

[@alannahhurley386]

*an egg

[@fishysmom1]

sadly this gave me more information in ten minutes then my health class in 8th grade did in four weeks... It also made more sense as well

[@mjocosta8275]

i love this channel. it makes me curious about so many things :) thanks for your quality content ♡♥♡

[@StevenEveral]

5:40 We're all here because we were that lucky sperm that broke through!

[@GlueC]

+Steven Manning Born winners.

[@FamAD123]

+Steven Manning Funnily enough, describing it like that actually undercuts how lucky we actually are.

[@zzzBoneSzzz]

The blue water on the desk is really rocking back and forth

[@vrstovsek]

I find this fascinating!

[@alyyyxxxx]

5:55 Correct me if you should, but my teacher told me that the sperm's mitochondria don't enter the ovum, with the fact in mind that mitochondrial DNA is maternal. So is the animation wrong or my teacher?

[@alexisreyes4179]

This is one interesting video. I know he's funny but he pretty much explains it. Omg I've Bern watching crash course for my global history classes

[@joshbobst1629]

Thank you, Hank. Doing a good job here, kiddo.

[@annidee]

They really crammed a huge amount of info into a tiny space of time in this! 😉

[@lexicheeseman8225]

7:01 him saying “lots of sex and babies” makes me so weirdly happy hahah

[@0oPowwao0]

Super nice video, again !! Thank you !! Thanks to Thought Café for these animations. So, do you that they could share some tutorial to learn how to create these animations ? because I need to make a presentation for my school. ;)

[@cleopatravenus1933]

Wow! It's published four days before my birthday!

[@4Nn1E]

So many people need to watch this...

[@mayumicervantes7587]

this channel never disappoints me

[@liambibes8492]

Thanks for school work

[@cloudnaeris2672]

im learning about this in class right now cool this will help me study ^.^

[@yuta2349]

Well explained.

[@l34CoNCreepy]

good job on the nightly show tonight :)

[@angelgrace1454]

You are amazing! thnk you! -philippines

[@psalmjirehmae4269]

how tf did sex become the next hunger games?!? 😂😂

[@prayaskandel8963]

Hunger Games was the next sex you mean

[@mayriiiiii-rh6pk]

Thank you very much sir and to the whole team, you thought me way more better than my Proctor did. ❤

[@abdobedo9428]

that's so cool hank , Thanks

[@lemanu1564]

Awsome Video!!!

[@BiPaganMan]

I believe the IUD does more than prevent implantation, I may have heard wrong but I remember hearing that it also prevents fertilization. I remember hearing this because they also stated that they aren't sure of the mechanism involved.

[@crashcourse]

+BiPaganMan It depends on the kind of IUD - hormonal IUDs are sort of like a 1-2 combo of the pill and an IUD in terms of how they work. Good, quick overview of this and other contraception methods in the +sexplanations episode on Pregnancy Prevention: kzbin.info/www/bejne/rpeUfJ-HYrWXrMk -Nicole

[@EpicFeury]

I laughed when he said "The Sex", spat coffee everywhere

[@rednexus55555]

that iconic opening theme will always be ringing in my ears

[@RNH2O]

Nurses here to support hank we ❤️your lectures!!!

[@hywodena]

I wish they would have covered The Pill in the birth control section. It's actually a very interesting chemical process

[@toniaa-y3559]

This video should played in every health class😂

[@yourfuturedocburenbeiya]

That video was amazing & thanks as always for these lecture videos!! It was hilarious at times but so informative! It’s also sad that females don’t need to have an orgasm for conception. I was laughing at the researchers with papers being thrown at them for criticism lol & I was really rooting for the middle sperm to make it pass the innermost membrane of the oocyte but some sperm blocked him like a hater lol. That moment describes a lot of male competition lol. I’m so impressed at the cute graphics!!

[@meetan-]

masterly presentation . .thanks

[@au9parsec]

I think you mean masturly presentation.. puns.

[@rk25741]

Please try to keep the font size a little bit bigger in the comment boxes. Smaller and fancy fonts becomes blurry @240p, please try to increase the font size a little bit more. Thanks. Keep up the good work. :)

[@colsoncustoms8994]

Lol this was one of the best so far.

[@alexc.1745]

BLESS YOU!

[@muntazeerreja9458]

Thanks crash course

[@abbyz13]

I need a crash course literature on One Flew Over The Cuckoo's Nest

[@QuorkQTar]

You should totally have linked to +sexplanations for more and in-depth information!

[@thepip3599]

How did I not learn this before now? Sperm dig little tunnels? Why on earth wasn't I taught that!!!?? I've possibly just learned more than I've ever learned about this since the "birds and the bees" talk. (Not counting the stuff I learned from the people on my bus in grade six. I learned many words from them)

[@Groaker]

Here's a bit of fun. Go open that video of the loop of the Baker Street Sax Solo and play it while watching this video.

[@stellahurd]

Love that me and my baby just waited till everybody else was tired trying to get inside the egg and was like alright I guess I’ll just try now 😂

[@YouAreStrong96]

My understanding is that IUDs primarily prevent fertilisation by creating a microenvironment that is hostile to sperm and ova, so that they can't actually meet. Is that only for the copper IUD?

[@Toocoolforschool573]

Good video

[@AwkwardFunk95]

I feel like we should have sperm appreciation day where we just pay homage to the brave and enduring little sperm cells that made that perilous journey and brought us all into the world. Thanks, little guys.

[@erica2912]

My finals for biology is tomorrow. Too bad Crash Course A&P still hasn't finished yet... :( I'll still watch this series tho

[@MicroCitrusXinfinityX9]

This never ends

[@CloverLane98]

I need crash course Physics!

[@mastertea8996]

After the placenta develops and decreases HCG secretion, does the corpus luteum then degrade?

[@toniaa-y3559]

Aside from the fact he adds "The" to Sex The Saxophone 😂😂😂😂 And the star wars music omg😂I'm crying

[@Tom-gy5ii]

got a good grade on my test :)

[@frankchen4229]

This video is eggcellent

[@HiThere-yy8zk]

What he said: "This takes a really long time to talk about." What he meant: John, please help me.

[@MelissaFlaquer]

Thank you SciShow for showing the internet that the first sperm to get to the egg just works hard for the next guy's entry path.

[@sansactionl5723]

starts singing "let's talk about sex"

[@AlKhttabAlSaqri]

CrashCourse + KaplanVideos = easy and best medical student life

[@SpeakShibboleth]

good thing I didn't take your word on the whole "totally safe for work" thing. Those sex noises were pretty loud.

[@ShariaTwain]

It looks like you need to replace that molecular model on your desk with a Snatom version. Derek would appreciate it.

[@A__ZhangWeibin]

I forgot to use an ear piece when I watch this 😱

[@roxana5490]

The sperm fighting the good fight got hoodwinked by the one that just swooped in! DOES THE NICE GUY FINISH LAST FROM THE VERY BEGINNING?!

[@hpebackwards]

"If I gesticulate enough then I can keep rabbitting on at 600 words per minute and they'll still get the message." Thanks though; in every other respect these videos are exceptionally helpful.

[@samhartley7755]

1:28 why cant my professors put this in their lecture slides?

[@madelineoconnor4026]

That fanfare was hilarious 😂😂

[@carterrobinder3254]

I like how if you search crash course the first VIDEO to turn up is this one

[@sylvie8070]

damn we had to watch this at school

[@TheNoa36]

So... Sex and fertilization is episode 42... So now we know that the bees and the birds are actually the meaning of life! Yay!

[@akmalsy159]

One thing I still don't understand even after finish studying A & P. How come the Zygote does not exhibit any cellular or DNA damage usually exist in adult cells, from which they are manufactured from? Essentially turning back the clock & become a newborn cell again.

[@thegoat5415]

lol dude epic intro briefing

[@StayTru101]

The Star Wars music killed me lol

[@eceatalay8329]

is there any chance in fertilization that sperm caught in the polar body? if so, what would've happened? from what I get, in the fertilization stage, the female pronucleus and the male pronucleus attract each other that the sperm doesn't caught in the polar body.