[Music] welcome back to our class don't forget to subscribe if it is your first time to visit our channel when you talk about preparing mechanism it's the process by which the diameter of the pure pill is being changed you find out that students tend to miss understand the public mechanism and the accommodation basically in accommodation you have talked about the lens you have talked about the suspense argument you have talked about the serial muscles while in epidural mechanism in this case you talk about the muscles in the iris and also talk about the pupil how much light is entering the eye that is what you call pupillary mechanism so is the process by which the diameter of the pupil is is ultimately to control the amount of light entering the eye how much light is entering the eye so in this case the light can be changed depending on bright or which is indeed so during brighter light then it means that more light is entering and then during them light it means that less light is entering so now the eye is supposed to add adjust so that at least it's the same amount of light which is entering the world just entering the eye how does that eye do this during brow light the radial muscles of the iris relax and then the sakura muscles of the iris contract when they contract the pure pill constricts it means that it gets smaller and then less light enters the eye how do we explain this why are these ones in different color i can say that r goes with r see what goes with the c r with r c with the c what does it mean i mean this r which is radio goes with relax and then c which is circular goes with contract radio muscles relax and then circular muscles contract simple if they contract then less light enters the eye that's what we need from there so if you look what circular muscles they call them sakura muscles because they're in circulars they're like in circles so that's why it's called the secular muscles and then radio muscles it's like a radius so that's why it's called radio radio muscles when the radio muscles uh relax when these muscles relax then the sakura muscles will contract when these now this one is your contract when they contract what happens it means that the diameter of the pupil the diameter of the pupil will decrease and then when it decreases it means that less light will enter the eye so it means that it's pushing this into the middle so that now this hole is what is small and then less light will be entering the eye so that is our with our and then you see with this you just need to know this radio muscles relax circular muscles contract less light the damage of the pupil becomes reduces and then less light enters the eye simple that is prolight what about dim light in dim light or dim conditions what happens the radio muscles will contract and then the sakura muscles will relax it's just the opposite of the other one so the pupil dilates when dilates when you talk about dilation it means that it becomes bigger it increases in size it becomes wider and then then more light will enter the eye so what does it mean i mean that now if you compare this one with the other one compare this one with the one in in brow light you find out that the pupil here is big even this distance you see that is it's big enough so what does it mean so i can abbreviate is that radio with the contract and then sakura with relax which means that ara with c and then it's with r i already said i tell my students um but i like esta i don't mix things up when you mix things up you mix things up in dim in in darkness it's when you mix things up so in brown light i don't mix these things up so the arrow would go with the iron let's see we'll go with this while in dim light because i mix them up ara will go with the c and then c will go with the r that's the meaning so it shows that during dim light will require more light and that's why now the pupil is supposed to become bigger it must dilate so that more light can enter to maintain the amount of light how much light is entering the eye so it must be kept constant that's why when the too much light when there is too much light outside then it means that the eye must constrict so that less light is entering or the same amount of light is entering so uh uh basically if you look at this you can compare now them during brown light it looks like this the pupil is small while dim light the pupil is big you see it there grammatically if you look at it there grammatically or structurally you'll find out that these ones the spaces here and the spaces here are not the same you see that here uh the space here the amount of light entering here is is is little or the space where light is passing is small compared to this so i'll say that this one is has constricted or this one has dilated so basically that's what you need to know during dim and bright light during dim light uh more light enters the eye while during bright light less light enters the eye [Music]