The phototransduction cascade | Processing the Environment | MCAT | Khan Academy

This explains phototransduction cascade which is critical to our sense of vision. By Ronald Sahyouni. Created by Ronald Sahyouni.
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Пікірлер: 87

  • @katharinalysy1518
    @katharinalysy15184 жыл бұрын

    "We'll just give it kind of a neutral face because it's ... bipolar." :'D I love this, makes me remember things way better!

  • @NicMNeves
    @NicMNeves8 жыл бұрын

    hey, i'd like to amend what you said about the naming of the bipolar cells, its actually not "bipolar" because it's on or off, its actually referencing the structure of the cell (it has two poles). This differentiates it from a unipolar cell, which is like a rod with only a single pole, transmitting a signal in 1 direction.

  • @suhheecook4910
    @suhheecook49102 жыл бұрын

    PhD student in biomedical engineering taking my last qualifying course ever... medical physiology. you're saving my life!

  • @S_a_Z_m
    @S_a_Z_m10 жыл бұрын

    Best part 0:49 but even without it, it's still a good video.

  • @casslovesyhuu
    @casslovesyhuu8 жыл бұрын

    This was such a great help! My physiology lecturer literally had no idea when he was teaching me this... Thank you! :)

  • @JealousyIsMadness
    @JealousyIsMadness7 жыл бұрын

    Thank you!!!!! I'm trying to absorb information for my Neuro final, this was super helpful

  • @MsChaosbutterfly
    @MsChaosbutterfly10 жыл бұрын

    One error: These cells do not produce action potentials. (Neither do bipolar cells.)

  • @SoDrigh

    @SoDrigh

    9 жыл бұрын

    So how are signals transmitted?

  • @jessmason2161

    @jessmason2161

    9 жыл бұрын

    ***** Graded Potentials. More efficient transmission over short distances.

  • @croin6020

    @croin6020

    7 жыл бұрын

    Amacrine cells are the first once who produce an ap

  • @halwa8128

    @halwa8128

    6 жыл бұрын

    true. when he said "action potential", i thought i misread my book. it's transmitted by the graded potential. correct me if im wrong

  • @guminjrng5610

    @guminjrng5610

    6 жыл бұрын

    They produce graded potential

  • @offsp25
    @offsp259 жыл бұрын

    Good presentation... i have more understanding point from you. Thank you.

  • @sofiab3829
    @sofiab38292 жыл бұрын

    You made this more clear than more neurophysiology teacher in optometry school! Thanks a ton

  • @lensmaticoptical4083
    @lensmaticoptical40835 жыл бұрын

    Millions of claps for you Sir. You are a real teacher..... Thank you

  • @fatimah9815
    @fatimah981510 жыл бұрын

    Great Video and very clear explanations! Thank you very much

  • @marianahozahoza6496
    @marianahozahoza64966 жыл бұрын

    With khanAcademy it feels like I found a treasure . 🗽 Thx a lot !

  • @trisch7499
    @trisch74995 жыл бұрын

    This is exactly what i need right now! Thank you!

  • @BenBezpark
    @BenBezpark10 жыл бұрын

    Thanks so much for the video. Was a great help glad to have you around :)

  • @yaytheo3289
    @yaytheo32899 жыл бұрын

    Really nice explanation, but the rod does not hyperpolarise only due to the Na channels being blocked, but also due to K channels remaining open and pumping K outside the cell. Other than that, great! ;)

  • @zas881
    @zas8814 жыл бұрын

    Very clear explanation! Thank you so much. Effort appreciated

  • @Shyam-wz5ro
    @Shyam-wz5ro5 жыл бұрын

    Hats off ...great video. Very thankful

  • @itskittyme
    @itskittyme4 жыл бұрын

    Just another beautiful example of Intelligent Design.

  • @TadanoCandy
    @TadanoCandy9 жыл бұрын

    Thank you for a very helpful video :)

  • @Sally6861
    @Sally68613 жыл бұрын

    Thank you! It makes more sense now!

  • @smileki89
    @smileki898 жыл бұрын

    do the same happen for the cones?

  • @jimmiller8875
    @jimmiller88759 жыл бұрын

    maybe someone mentioned this in previous comment (apologies if so): opsins don't have seven subunits, they have seven transmembrane helices

  • @existentia1krisis
    @existentia1krisis4 жыл бұрын

    I have to turn down most videos because they're super loud, but with this one, I had the volume turned up all the way on youtube and on my computer settings and still had to turn on subtitles. Other than that, great video!

  • @robertryansantamaria75
    @robertryansantamaria754 жыл бұрын

    Very nice... :) additional input, metarhodopsin II activates transducin...

  • @stevenk113
    @stevenk11310 жыл бұрын

    The 11-cis conformation drawing is a little misleading. The branch should be angled downward after carbon 11 to indicate it being "bent"

  • @selenozmen2251
    @selenozmen22519 жыл бұрын

    Nice way of telling a boring subject, thank you very much for the explanation :))) Now that I understand the mechanism, I don't have to memorise it ;)

  • @MrPridizzle
    @MrPridizzle3 жыл бұрын

    Thank goodness for 1.75x playback speed.....

  • @kaijaeseri8990
    @kaijaeseri89905 жыл бұрын

    Thank you for the elaborate explanation

  • @jazminbrantley3325
    @jazminbrantley33257 жыл бұрын

    Great video. Very helpful.

  • @nimraaslam7715
    @nimraaslam77158 жыл бұрын

    Thank you so very much!

  • @jiedeng3934
    @jiedeng39346 жыл бұрын

    Thank you!!

  • @karedo9924
    @karedo99246 жыл бұрын

    you sir rock!

  • @slobberdan8428
    @slobberdan842810 ай бұрын

    Beautifully explained thanks

  • @oop8599
    @oop85993 жыл бұрын

    thankyou so much :D really easy to understand

  • @Safestreet
    @Safestreet7 жыл бұрын

    Very nicely explained.

  • @anamika4088
    @anamika40883 жыл бұрын

    U made it really easy to visualize

  • @itstheannas
    @itstheannas Жыл бұрын

    Explanation so clear I can finally sense my cones when ma man changed the colors of his markers

  • @txaitxaitxai
    @txaitxaitxai4 жыл бұрын

    the name "rhodopsin" is actually coming from the latin for "red" (rhodo-) not because it's in the rods. That's just a way to remember it.

  • @keighleyhayes
    @keighleyhayes6 жыл бұрын

    let's give him a little smiley face because he's happy

  • @evanpham7881
    @evanpham78813 жыл бұрын

    Actually crying in happiness!

  • @acevedoyadi
    @acevedoyadi3 жыл бұрын

    Thank you.

  • @SkyZone57
    @SkyZone577 жыл бұрын

    I just love you

  • @laured7593
    @laured75938 жыл бұрын

    THank you so much for the video, it helped me so much! I do belive though that the word "rhodopsine" does not come from "rods" but from the Greek "rhodon" meaning "pink", but I am sure someone mentioned it already.

  • @jonathanklein1133

    @jonathanklein1133

    8 жыл бұрын

    Yup, and the protein in cones isn't called conopsin it's called iodopsin

  • @guminjrng5610

    @guminjrng5610

    6 жыл бұрын

    Not pink its purple

  • @miss0noodle
    @miss0noodle7 жыл бұрын

    Anyone else hear sweet birdie chirps around 7:25?

  • @mahtabfotovat4908
    @mahtabfotovat49082 жыл бұрын

    Hello, thank you for this amazing video, I have both a question and and a suggestion, Q: do you mean outer nuclear layer and inner plexiform layer by mentioning two types of bipolar neurons or actually there two distinct types of them? And my suggestion is it would be nice to have clarification when when have Rhodopsin kinase activity and its association with reduced activity of transducin also maybe the role of arrestin, thank you

  • @user-iu7yu6us7i
    @user-iu7yu6us7i2 ай бұрын

    Like this can you explain what happens in cone cell

  • @MarttyLovato
    @MarttyLovato8 жыл бұрын

    i love smiley faces on rods and cones

  • @queenofunderland

    @queenofunderland

    8 жыл бұрын

    Many of us , like me , turn to be crazy 'bout it

  • @MsTommyknocker
    @MsTommyknocker9 жыл бұрын

    I dont understand. Wouldnt the rod be releasing inhibitory neurotransmitters in its "on" state since the bipolar cell is off when the rod cell is on??

  • @jimmiller8875

    @jimmiller8875

    9 жыл бұрын

    MsTommyknocker it could, but doesn't; vertebrate photoreceptor cells (rods and cones) release glutamate from end opposite to outer segment to bipolar cell, so in dark they are "on"; cGMP-regulated channels in outer segment essentially "leak" sodium and calcium into outer segment and keep the cell relatively "depolarized" in dark (so glutamate is released), closing these channels decreases "leak", makes the cell more "polarized" (membrane potential more negative) and glutamate release is decreased

  • @intj1434

    @intj1434

    6 жыл бұрын

    ^What I learned is that, you know how the video mentions that there are 2 types of bipolar cells? On-bipolar cells have mGLuR6 receptors (G-protein coupled metabotropic receptors) on the terminal where they synapse with the photoreceptors. Off-bipolar cells have ionotropic receptors on the terminal. Photoreceptors always release glutamate as their neurotransmitter. mGluR6, when bound to glutamate, actually closes the cation channels on the On-bipolar cells, hyperpolarising it. So even if the photoreceptor is depolarised, On-bipolar cell coupled with it will be hyperpolarised. Ionotropic receptors on the other hand allows cation influx into off-bipolar cells, depolarising it. Which one of these happens depends on the amount of glutamate released by the photoreceptors (less if the rod is off, more if it's on) and what type of bipolar cell is coupled with it.

  • @debbee5898
    @debbee58985 жыл бұрын

    I've read that there are 'on-centre bipolar cells' and 'off-centre bipolar cells', correct? When light hits rods, the off-centre bipolar cell depolarizes and releases a neurotransmitter. when no light= rod on= off-centre bipolar cell depolarizes and releases neurotransmitters. My question is which neurotransmitters the bipolar cells release and if we need to know that on the MCAT.

  • @_adi_dev_
    @_adi_dev_6 жыл бұрын

    Rhodopsin isn't named for what type of cell its in, it was named for its colour

  • @tova6273
    @tova62738 жыл бұрын

    Great video. One thing I don't get- is phosphodiesterase another name for cGMP? Or are they different things?

  • @Vimarphil

    @Vimarphil

    8 жыл бұрын

    +Tova They're different : phosphodiesterase is activated by the alpha subunit of the rhodopsin, and then takes cGMP from intracellular milieu to turn it into GMP ! I hope I helped and that there's no english mistakes !

  • @NLSoulja99

    @NLSoulja99

    8 жыл бұрын

    cGMP (cyclic guanosine monophosphate) and PDEs (phosphodiesterases): PDEs are those enzymes that catalytically convert the so called "second messenger" cGMP to GMP (by breaking a phosphodiester bond). When cGMP levels are elevated, PDEs are then responsible for decreasing its levels back to normal, thereby being responsible for its regulation. It's also interesting to know that the actual sex drug Viagra (Sildenafil) is just an inhibitor of cGMP-specific phosphodiesterase type 5 (PDE5). This enhances the vasodilatory effects of cGMP in the corpus cavernosum. Cyclic GMP has literally dozens of functions, apart from vision and erectile (dys)function, also is implicated in other cellular functions, like proliferation, apoptosis etc.

  • @halwa8128
    @halwa81286 жыл бұрын

    does the cone cell have the same cascade as well?

  • @user-kk5ep8sk6z
    @user-kk5ep8sk6z3 жыл бұрын

    How does rods have power to convert it? How does the process take place?

  • @monday2471
    @monday24715 жыл бұрын

    what's the purpose of having on and off bipolar cells?

  • @adityarizqi8429
    @adityarizqi84293 жыл бұрын

    Please help me, how can or why the Alpha cell come over to bind with phospodiester?

  • @pfln
    @pfln10 жыл бұрын

    isnt phosphodiessterase an enzyme?

  • @nadaid8449
    @nadaid84495 жыл бұрын

    I need to understand how the rod work please anybody can help my it's confuse for my

  • @EDUARDO12348
    @EDUARDO123487 жыл бұрын

    at 4:40 did anybody else hear birds or am I just studying too much?

  • @oviaxanax5645

    @oviaxanax5645

    5 жыл бұрын

    EDUARDO12348 i did mate

  • @BakrAli10

    @BakrAli10

    5 жыл бұрын

    @@oviaxanax5645 yeah we are studying too much

  • @fadisoltan5113
    @fadisoltan51133 жыл бұрын

    fucking life saver

  • @IK-fg4gw
    @IK-fg4gw6 жыл бұрын

    No mention of opsin?

  • @lorrainebennett9187
    @lorrainebennett91877 жыл бұрын

    laymans terms my rods are in an umbrella dome and gold whats the meaning

  • @pfln
    @pfln10 жыл бұрын

    And arent the ganglion cells the one that initiate action potentials, not bipolar cells? Im just making sure b/c i have a physio test thursday and im panicing HEEHOOHEEHOO

  • @francoisjeffery1606
    @francoisjeffery16069 жыл бұрын

    reIHnal

  • @user-gi2vc5xg5f
    @user-gi2vc5xg5f10 ай бұрын

    자막애 한국어 지원부탁드립니다.

  • @ShiranaiNeko
    @ShiranaiNeko6 жыл бұрын

    It's a good video but you didn't really explain why it's called a cascade

  • @rachelwhipple677
    @rachelwhipple6777 жыл бұрын

    what about scotopsin?

  • @purplestains7426
    @purplestains74266 жыл бұрын

    very basic video... missed out on many details thumbs down!