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
"We'll just give it kind of a neutral face because it's ... bipolar." :'D I love this, makes me remember things way better!
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.
PhD student in biomedical engineering taking my last qualifying course ever... medical physiology. you're saving my life!
Best part 0:49 but even without it, it's still a good video.
This was such a great help! My physiology lecturer literally had no idea when he was teaching me this... Thank you! :)
Thank you!!!!! I'm trying to absorb information for my Neuro final, this was super helpful
One error: These cells do not produce action potentials. (Neither do bipolar cells.)
@SoDrigh
9 жыл бұрын
So how are signals transmitted?
@jessmason2161
9 жыл бұрын
***** Graded Potentials. More efficient transmission over short distances.
@croin6020
7 жыл бұрын
Amacrine cells are the first once who produce an ap
@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
6 жыл бұрын
They produce graded potential
Good presentation... i have more understanding point from you. Thank you.
You made this more clear than more neurophysiology teacher in optometry school! Thanks a ton
Millions of claps for you Sir. You are a real teacher..... Thank you
Great Video and very clear explanations! Thank you very much
With khanAcademy it feels like I found a treasure . 🗽 Thx a lot !
This is exactly what i need right now! Thank you!
Thanks so much for the video. Was a great help glad to have you around :)
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! ;)
Very clear explanation! Thank you so much. Effort appreciated
Hats off ...great video. Very thankful
Just another beautiful example of Intelligent Design.
Thank you for a very helpful video :)
Thank you! It makes more sense now!
do the same happen for the cones?
maybe someone mentioned this in previous comment (apologies if so): opsins don't have seven subunits, they have seven transmembrane helices
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!
Very nice... :) additional input, metarhodopsin II activates transducin...
The 11-cis conformation drawing is a little misleading. The branch should be angled downward after carbon 11 to indicate it being "bent"
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 ;)
Thank goodness for 1.75x playback speed.....
Thank you for the elaborate explanation
Great video. Very helpful.
Thank you so very much!
Thank you!!
you sir rock!
Beautifully explained thanks
thankyou so much :D really easy to understand
Very nicely explained.
U made it really easy to visualize
Explanation so clear I can finally sense my cones when ma man changed the colors of his markers
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.
let's give him a little smiley face because he's happy
Actually crying in happiness!
Thank you.
I just love you
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
8 жыл бұрын
Yup, and the protein in cones isn't called conopsin it's called iodopsin
@guminjrng5610
6 жыл бұрын
Not pink its purple
Anyone else hear sweet birdie chirps around 7:25?
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
Like this can you explain what happens in cone cell
i love smiley faces on rods and cones
@queenofunderland
8 жыл бұрын
Many of us , like me , turn to be crazy 'bout it
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
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
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.
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.
Rhodopsin isn't named for what type of cell its in, it was named for its colour
Great video. One thing I don't get- is phosphodiesterase another name for cGMP? Or are they different things?
@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
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.
does the cone cell have the same cascade as well?
How does rods have power to convert it? How does the process take place?
what's the purpose of having on and off bipolar cells?
Please help me, how can or why the Alpha cell come over to bind with phospodiester?
isnt phosphodiessterase an enzyme?
I need to understand how the rod work please anybody can help my it's confuse for my
at 4:40 did anybody else hear birds or am I just studying too much?
@oviaxanax5645
5 жыл бұрын
EDUARDO12348 i did mate
@BakrAli10
5 жыл бұрын
@@oviaxanax5645 yeah we are studying too much
fucking life saver
No mention of opsin?
laymans terms my rods are in an umbrella dome and gold whats the meaning
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
reIHnal
자막애 한국어 지원부탁드립니다.
It's a good video but you didn't really explain why it's called a cascade
what about scotopsin?
very basic video... missed out on many details thumbs down!