Role of the sarcoplasmic reticulum in muscle cells | NCLEX-RN | Khan Academy

[@FeelgoodInc212]

I'm a first year Medical student. I just want to thank you for these great videos that make the difficult things you read on the slide shows from school, seem so easy...

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Davíð Jónsson nice lol so how was med school, did u graduate ?

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ya, touche´how was med school? things going good? :)

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So? Did you graduate? How did it go?

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@@martinajaya975 Yes I did graduate 2 months ago :) - working full time as a doctor now.. best of luck to all of you!

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You are a life saver. I'm trying to squeeze 8 months worth of study into 3 days before my exam (bad idea kids never miss your classes/ lectures) and your videos are literally helping me power through my syllabus.

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how did it go ? did you pass?

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omg this was a year ago haha. Yes I did pass now I'm revising for my exams next month. And I didn't follow my own advice and left everything till the last minute again lol

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HAHA Nina you are horrible just like me but this does not work in medical school :( I studied my ass off the last two weeks still can't keep up

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how could you pass with 3 days of studying?

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I hope I'm never your patient

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Can I just say that I actually love you. You are genuinely saving lives with these videos that are so fantastically explained and illustrated. Thank you.

[@MassimoMD]

My physiology professor spent two weeks on muscle contraction. I never understood it, and two ~10 minute videos made it SO much clearer. Thank you.

[@Rhibbler022]

You have just saved me from a cell bio teacher with a thick German accent and no understanding of how to explain concepts or teach. Kudos to you, my fine fellow.

[@hould6611]

For those curious: The "mystery box" is now understood to be a co-op of two proteins. The 1st, bound to the t-tubule, is called a "DHP-receptor". It is a modified version of a Ca2+ voltage gated channel, altered to serve as a volt-meter. Ryanodine, the 2nd protein, is embedded in the SR. As an action potential moves into the t-tubule, charged amino acids in the DHP receptor signal the ryanodine receptor, itself changing shape to allow Ca2+ ions to flow into the cytosol, then to the troponin.

[@TheTamtamm1]

this is amazing...nothing in my textbook or on the internet explained what exactly the sacroplasmic reticulum is for. Beautiful explanation, you just helped me get 20 points on my final! :)

[@hamie7]

I read my books and its all just word floating round my head! Then I watch these vids and they all settle in place! Its like I can actually here them clicking in to place!ha Thanks so much you're doing a great job!

[@mosam4]

Can't express how much this video has helped me! I might actually do decent in my first year :') thank you!

[@hoarski]

I learnt more in this series about the neuromuscular system in 30 minutes than my 4 hour graduate level exercise physiology class. You are a genius Sal.

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when we die and meet god, Ill make sure to say something nice about you. Thank you

[@jolopez9501]

I finally understand this concept. Thank you!

[@sacc7734]

This video indirectly answered my question about how malignant hyperthermia works. Strong work.

[@Arham1716]

Thank u so much Sal...Love ur videos ❤❤

[@MikeB-sp6gp]

Beautiful-- Clear-- Explanation. Thank you.

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most effective use of paint i've ever seen.

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[@pbyrne72]

Wow. Great explanation. They say the mark of great intelligence is the ability to explain highly complex subject matter in a very simple, concise, and easily relatable manner. You sir, are an intelligent man.

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thank you so much you make it so easy

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thanks million times,u save my misunderstood lecture.God bless u,

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Thank you thank you. This really pulled it all together for me.

[@superGoodjuju]

you are a fabulous teacher! I never once got lost (as I have in many other videos) and your voice is great:)

[@sgtOOX]

excellent. now if you are so inclined, time for some genetics and microbiology, and organic chemistry :( these videos are great for review though an excellent complimentary source for the curriculum. i will probably be using the calculus videos next semester for a refresher and physics as well to keep my edge. thanks again splendid job as always.

[@sabrinagerges6412]

Super helpful! You should remake this video with the new findings about these structures and processes (e.g. ryanodine as a receptor to stimulate calcium ion release).

[@ohioSPIRIT]

GREAT job explaining. Keep it up- you're helping a lot of people.

[@nadiacharafi8815]

great video but I think its time now to update the information of the mystery box is actually called triad complex composed of dihydropyridine receptors (DHPR) voltage sensing channels of the T-tubule and the sarcoplasmic reticulum calcium channels ryanodine receptors (RyR)

[@princetamrac1180]

Amazing and easy explanation thx man

[@guzelkizz06]

Your videos have the same subjects as my lessons! I'm studying medicine, and this stuff is amazing!!

[@03rsfdance]

Selin B. How is your studying going now? I’m a potential studier lol

[@shannonsmith5623]

This helps understand the protein complex aspect of the muscle cell a little better. I am still trying to understand the terminal cisternae of the SR in more depth and their receptors that push against each other and excite each other to release the stored calcium ions.

[@RockyBalboa211]

Yeah this is skeletal muscle, people sometimes get confused.. yet, just remember smooth muscle and striated muscle (Skeletal muscle and Cardiac muscle)! :D

[@FarrahGreye]

youre the greatest man on the earth

[@virupannamedikinal]

Thank you so much Sal Sir

[@Ph0be]

I love you Kahn, you're doing gods work.

[@kristinapayne6854]

This is amazing.. You helped me so much with the diagram of sarcoplasmic reticulum

[@ledionroci1502]

You are absolutely incredible. Thank you 🙏

[@Moemenk]

You're the man! BTW As stated in the comments below learned that ryanodine communicates with DHP (Dihydropyridine ) receptors (the big question mark in the video). Easy for me to say 8 years later

[@myriad909]

Great lecture Khan! Just a small correction. When referring to the "mystery box," you mentioned the possibility that "ryanodine" may be involved. I believe you meant to say ryanodine receptor. The ryanodine receptor is a selective calcium channel which operates via a process known as calcium induced calcium release. Ryanodine, on the other hand, is a plank alkaloid and a high affinity binding partner of the ryanodine receptor and is able to inhibit or activate this calcium channel (depending on the concentration). Ryanodine receptors are prevalent throughout skeletal and cardiac muscle and are crucial in the physiologic processes you're describing here. Great work!

[@MadelMac]

Agreed! Just went over this in lecture, and apparently the Ryanodine receptor acts much like the calcium channel of the pre-synaptic neuron in that it is stimulated by the sodium from the action potential carried across the t-tubule. This channel then opens up and releases calcium which stimulates calcium channels on the sarcoplasmic reticulum to open up and release even more calcium to the surrounding muscle myofibrils. According to our 2007 textbook that is! This protein bridge could be an even more recent discovery

[@myriad909]

MadelMac Good point! To be completely accurate, ryanodine receptors (RyR-; located on the SR) are indirectly activated by sodium. The RyR is a prototypic Ca2+ induced Ca2+ release channel, which means that the most potent activator of RyR Ca2+ channel is Ca2+ itself. Other direct activators include the second messenger cyclic ADP ribose (cADPR).

[@213151315131514]

This just solved a question I've been confusing for weeks !!

[@riyabhatiya2571]

Just perfect anything cant be better than a perfect concept.

[@lawyerdoctor]

Great video. Thank you for the explanation and the enthusiasm.

[@03rsfdance]

Sitting in Starbucks studying for my Animal physiology test on Monday and I go “ahhhhh!” Really loudly because I finally get how the Ca2+ gets into SR

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You saved my ass. Oh my God, you are the savior of the common student!

[@الأستاذمحمدأبوعودة-أحياء12]

Great... Thank you.. really great

[@LuckyHamster819]

This video helped me a lot in my studies! Thank you SO much!

[@tasadayl]

now that we have a better understanding of the mystery box can someone do a follow-up video explaining it?

[@leahevelee]

thank you❤

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[@dumar88]

Awesome explanation! Thank you!

[@ranahanna160]

AMAZINGLY CLEAR

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Masha Allah...

[@haddadelizabeth]

wowowow thank you. you're a lifesaver.

[@motherssmile]

i was watching this in the living room. There was kind of an argument going on. When you raised your voice when you said sarcoplasmic reticulum it suddenly got quiet in the room. :] It was a really funny moment

[@weiwei4366]

Thank you, you are a fantastic teacher :))

[@theladysilverwings]

YOURE A LEGEND

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[@Vytagus]

I like how you make all this stuff easy to understand, by the way can you make oremvideos regarding human anatomy

[@robertadams2453]

The "mystery box" is related to DHP and Ryanodine Receptor.

[@Halahmed12]

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Awesome ! Love you

[@iazahussainzz]

learning this for my exams at the beginning of second year as we didn't have first year exams due to covid 19. ask me how im doing in 5 years :)

[@hould6611]

you're videos are GREAT btw! I apologize for being terse on my previous post. There's a word limit!

[@MrPridizzle]

Sounds good mate, see you in the next video :) Cheers!

[@TravisGriffinTron]

I suppose we all need heroes nerded out about certain topics. Everyone who watches this video will be happy to know that in the case of Saroplasmic roles, it's not me.

[@bazilamir505]

keep up d good work

[@lailamohd9267]

I'm confused on what is the purpose of T tubuls, please help

[@6o4sage]

What happens to the calcium after its pumped back into the SR? Is it re used over and over again for muscle contraction? How many times can the same calcium ions be reused? Are they eventually metabolized and replaced by more calcium ions from the extracellular fluid???

[@MMM-np4oo]

WOW 👍👍

[@Emmadril]

Omg he’s so excited LOL

[@cecillereloj867]

Wait, the mystery box ISN'T DHP and ryanodine receptors?

[@alex-nv8rk]

+cez reloj It is! The video is from 2010, so the research at that time hasn't discovered that yet. Dihydropyridine receptors senses the electrical signals, which then trigger the opening of Ryanodine receptors, which in turn release Ca2+ across all the membrane of SR.

[@phani991]

+Alexandr Pulbere I have an interview next week on the same topic, if you know can you suggest a couple of reviews on this topic..? Its all very new to me, cheers

[@dr.hibayousuf7840]

So what will be the voltage here?

[@mustavogaia2655]

God watching this video: "No way I could design that, man."

[@Stelnice]

Do you need ATP to pump Calcium ions out of the sarcoplasmic reticulum? :)

[@clarisse4610]

What happens if the calcium was not return back into the sarcoplasmic reticulum?

[@desp0ina17]

@hould6611 Could you please make it more clear for me.. It might not get more simple than this but could you please try? I have exams in 3 weeks so it would be perfect if I add something that I didnt hear from the lectures.. I just lost it a bit after the second protein.. The second protein is replacing what??? Thank you for your help!:)

[@tyleromalley9333]

So can you do a bicep curl without any utilization of the tricep

[@dontaye6558]

All your muscles are slightly flexed for the most part you arent using triceps when bicep curling

[@simplyyjhez]

for flexion (actually curling part)-no, but for extension (lowering of your arm to relax and begin the next curl), yes.

[@jennifergwishiri8326]

Anyone know what happens if the the DHPR is not activated

[@renamicheletti8613]

My teacher don’t even explain. Am learning what I paid For🤦🏻‍♀️🤦🏻‍♀️

[@xtine19]

is the cytoplasm the same term used for sarcoplasm?

[@Arsh.99]

yeah its the same thing just that it is for the muscle so its sarcoplasm

[@apes882003]

Im sure the mystery box is a ryanodine receptor

[@xlongwu]

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[@7azem3mad]

greaaaaaaaaaaaaaaaaaaat

[@soccerg20101]

don't muscle cell's only have voltage gated Ca2+ channels?

[@denominator94]

Noor J no

[@bballev2]

dom rolfe your wrong. there are Voltage gated ca channels - im pretty sure thats what activate the ryanodine receptors

[@bballev2]

Ev Mannion dihydroperidine receptors are the voltage gated ca receptros Noor J was asking about. had to look that up, but makes sense - they are the target of DHP ca channel blockers on smooth muscle :P fucker

[@denominator94]

Ev Mannion No, your wrong

[@bballev2]

ya ya. get some references or explanations to back up your Nos

[@amandaphung8056]

I'm enrolled in an Anatomy course at community college with a crappy professor who links to your videos instead of making her own lectures. I love your vids, but I would much rather give you my money than the college.

[@masterzaraki]

Is that...is that "gym douchebag" style advertising spam? Only here cause the word muscle is in the title? I find this amusing!

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