Primary hemostasis | Advanced hematologic system physiology | Health & Medicine | Khan Academy

During primary hemostasis, a platelet plug is formed to rapidly stop the initial bleeding after injury. Learn about the different steps involved in primary hemostasis: vasoconstriction, platelet adhesion, activation and degranulation, platelet aggregation. Created by Gricelda Gomez.
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[@MonnieMoo318]

THIS VIDEO IS ABSOLUTELY AMAZING!!!! I actually am understanding!! :D THANK YOU KHAN ACADEMY!! :D

[@mohamedjatte9145]

Thank you for your simple explanation

[@naidoi1]

I absolutely love khansacademy ☺️☺️☺️

[@safirazed7375]

Awesome! Thank you so much!

[@LD-jp3iu]

Great explanation. Really helped explain the details of primary hemostasis from First Aid 2017

[@majedsaeedy1910]

Amazing explanation, clear and informative diagrams. I was watching a lecture at my university and didn't really understand primary hemostasis, but this video really cleared it up.

[@user-uu3xy5ri1p]

thank you khan academy, for helping me with almost every exam TT

[@minhlucnguyen7614]

Thank you so much for blowing up my mind, this video is super amazing and easy to be understood!!!!

[@ahmedgamaleldeen8451]

Excellent !

[@tonyejack2069]

i love this video thanks!!!!

[@noorabd5691]

Really thank u... God bless ya❤️❤️

[@cormacdoyle3435]

This video is so helpful, thank you

[@ALIMAX20072]

i wish u were my professor :(

[@a.s.america]

great! i almost got it! thank you

[@maryannekastner]

great video!!

[@demonskwirl9462]

this is outstanding. very concise, understandable, easy to remember

[@PinkPeony21]

Fantastic video! Thanks

[@rahmiaziza4698]

this is really helpful! thanks a lot 😊

[@sarajade1322]

great work ..

[@user-zz1qd1pe7l]

Great explanation. Thank you!

[@yashika5006]

These are really helpful......thank you

[@asmahaque8558]

YOU ARE BRILLIANT!

[@fanvd]

thank you!

[@unrivaled37]

Thankyou!

[@jmoney8630]

I don't know why people are complaining about the voice over. I thought it was perfect. She was talking like an actual person does when they are talking to you. And personally, that helps me listen better. Would people rather it be completely monotone? To each their own I suppose.

[@pitiful_sentence]

THANK YOU!!!

[@mrcharlesjohnson]

Str8 fantastic video thnx so much for explaining this in a simple manner

[@nikolaoskormpis3511]

Really good explanation, thank you

[@nativedamascus8819]

Great work thank you

[@bahiachibi895]

Wonderful amazing thanks

[@michaelgilman4068]

Thanks pretty darn good overview. My Lippincott Pharmacology text fills in some details but your narration and illustration make the concepts and substances a bit easier to latch on to...One small note of criticism, meant constructively, the "hole" in the vessel is called the lumen.

[@gangsardamai8139]

thankzz

[@mohamedalimegahedahmedrash3822]

THANK YOU

[@nadeemrabi647]

I love you !

[@kv9430]

thank you for your sharing ms, this is best, i really analyze the process of primary hemostasis, thank you, i hope for you response 😇

[@reemalhazza4868]

Thank you and love you 😍

[@nazmaahmed1544]

Thank you

[@abrardesrt]

pravo... thx thx thx ❤❤❤❤❤

[@tahirakhtarvlogs5637]

Thank you 🙏

[@hudapediatric3492]

nice helpful vedio thanks alot

[@MrShishpal]

Great information

[@1412Z]

thank you! very helpful video, i recommend also watching the 2ndary hemostasis video by Khan Academy

[@leopoldoansantos]

Great, thank you! What is the name of this software?

[@alaaelshiekh3064]

great vedio

[@amna7629]

Gorgeous 🤝🏻✨

[@lovely-zg6di]

y are amazing tnx

[@kaelashawa8305]

thankyou

[@GigglrTv]

Hey, do u com(ment) here often?

[@mandisangema2568]

You saying fibrinogen leads to platelet aggregation? Doesnt have to be cleaved to fibrin by thrombin first?

[@jowanismail1942]

Nice one 💕

[@priyankamidha5071]

Thank you so much, amazing video. I have a question if someone can help me with it - When an injury occurs, why do we only lose NO and prostacyclin (vasodilators) with the blood and not the vasoconstrictor, endothelin?

[@rahmiaziza4698]

because the winner is endothelin :) I mean like vasoconstrictor more stronger while injured, so the vasodilators gonna fail with it. Hope it's gonna help u,guys😊

[@rubaali7886]

I can be clear with u guys I wouldn't make it through one day before exam without u 😭🙏

[@alexcoreablecoreable]

for the last part of this video, isn't it fibrin instead of fibrinogen? i thought fibrinogen needs to be converted to fibrin and then it can form cross-linked mesh?

[@nbgoodiscore1303]

I know I'm late but fibrin only exists in secondary hemostasis.

[@sharonzell2308]

I can get sound on other videos but not the primary and secondary hemostasis?

[@sandervdcp3513]

what is the program for the drawings?

[@sofiajadez7126]

thank you!!!!

[@laboniroy-ed8qp]

Best

[@mikeearls126]

its cool to learn here definitely....but the high speed video and high speed talking of a person who knows everything about the topic makes learning harder (have to constantly stop video) teaching is not just spewing out stuff as fast has humanly possible....but actually considering who is watching....of course IMHO

[@blackyrocky7438]

First response to vascular injury is vascular spasm or vasoconstriction to reduce bleeding. Then platelet plug, aggregation, and thrombus form. Injured or damaged endothelial cells release endothelin which will act on smooth muscles to contract and ultimate goal will be vascular spasm. Particularly endothelin will trigger release of calcium in smooth muscles which will cause contraction

[@micahrapata5085]

So just to clarify, does fibrinogen not fibrin aggregate platelets via their activated 2b/3a receptors?

[@mohammedabdullah5989]

Fibrinogen aggregates the platelets via their receptors. Fibrin is formed from fibrinogen by thrombin.

[@AIJ101]

Great video however I'm not an engineer but if a bridge falls out or half of it does it would be common sense that you don't use the bridge because the integrity of the bridge is no longer intact

[@davidt8274]

The alpha granules contain fibronectin, not fibrinogen - fibrinogen itself has to be activated by thrombin to become FIBRIN and is stickier - it polymerises with other fibrins and stuff, and only binds to fibronectin when mediated by factor VIII. Fibronectin... don't polymerise, they bind to fibrin when Factor VIII comes into play and catalyse the process (factor VIII stabilises fibrin and 'contracts' it, closing up wounds), Fibronectin mainly binds cell membranes through connecting with integrin molecules, which means it binds cells to cells. Platelets basically start working on long term healing the moment the are activated, but is relatively inefficient until fibroblast cells come in and form huge amounts of connective tissue etc.

[@sofiamosca2714]

Alpha granules contain both: fibronectin AND fibrinogen

[@firstnamelastname5474]

They have both, actually.

[@dhooy7150]

I don't understand the purpose if vasoconstriction as a result of damage to collagen. Wouldn't this cause more blood to be lost?

[@AssassinNasa16]

Vasoconstriction will increase the flow resistance therefore reducing the flow of blood to the wound site.

[@gabrielsanchez8501]

Fibrinogen is produced by the liver. I think you meant to say "Fibronectin".

[@Dr.Ankesh]

fibrinogen and fibronectin both are present in alpha granules of platelets

[@jannasalam]

the content is good but the voice over is so poor!

[@abdullahmohammad6803]

No its not

[@muriellejean-baptiste7511]

too fast, too fast! lol but still helpful

[@lisadonayre6654]

The voiceover/dictation of the topic is SO distracting... still, helpful information..

[@ramzehythmoni1777]

I think ..stop saying that .. Plz .

[@graciechandlee8879]

your constant pausing in your sentences is killing me.

[@alaaelshiekh3064]

no she is cute u fuck

[@Mrscarfire1]

It is a very good video but please, please, please stop moving the cursor around when you are not writing! You wiggle it around and shake it constantly, it is distracting and annoying. I would quit watching this video except it was assigned by my instructor.

[@anglcasncn]

You're so hard to understand it makes me sleepy. Prolly because of how you talk. But thanks for the effort

[@BrunaNathaly]

thank you!

[@Marlencheeen]

very good job !!!