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80 Cards in this Set
- Front
- Back
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What is transduction? |
chaining from one form of energy to another |
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why do we need transduction? |
because our nervous system is electrical and other system like vision are not |
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what is distal stimulation? |
it is when the light comes off the object, the object bounces light into your eye Different colour reflect the light to your eye (red only reflects red) |
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Proximal stimulation |
light being shone on to the back of your eye (retina) we are really responding to the pattern of light shown onto your eye |
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what type of energy is hearing |
it is mechanical energy (when molecule hit up against one another) |
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how does perception happen in two stages? |
through transduction and interpretation |
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what is interpretation? |
- we often go beyond what is being shown (our brain fills in the black, trying to make sense of the information) - ex illusory contour figure or netra cube |
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the physiology of perception |
it is the internal electoral system (it is a system of communication, taking energy / info to one place or another) |
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what is the nervous system? |
- the nervous system is just a big communication system - the basic element of the nervous system is a neuron - the basic part is the cell body and the nucleus and dendrites |
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Dendrites |
dendrites purpose is to receive information |
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Axons |
axons is to send information (is can actually be very long, in humans it can be a meter long), they send the electronic message down the cell |
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how does the width of the axon then determine the speed? |
- the width of the avon, the size of the axon determines how quickly it can traveles - this is important because the body has to priorities of what info is most important - smaller the slower it goes, the larger the faster it foes |
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what about the axon in invertebrates? vertebrates? |
in invertebrates the only thing that determines how fast the signal travels throughout the axons is the width. - but in vertebrates, there is also the myelin sheath that also control the speed, with myelin it send thing fast why? because they current jumps from one place to another |
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what is Multiple Sclerosis? |
- MS, what happens is that there is a break down in the myelin sheath, thus the current is not working |
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is there a kind of person that does not have much myelin? |
- babies why? because if they had the myelin then there head would be much bigger, then they could not give brith - from the head down and the centre to the periphery, this is how the myelin grows in |
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how is info transferred inside a single neuron? |
- it is called pre synaptic transmission - atoms have a center, in this centre there is a neclues (they have protons +) and floating around is the electrons (-) - the number of protons is what differentiate one element from one another, they are the same of the neuron - the number of protons is what differentiate one element from one another, they are the same of the neuron - in the axon there is extracellular fluid and on the inside there is the intracellular fluid - the membrane is the coating on the outside - the extracellular fluid is full of sodium ions (they are positive) - the intercellular fluid is full of amino acids (they are negative - the membrane is selectively permeable - then you attach a voltmeter, one on the membrane and then in the extracellular fluid - the voltmeter, they is looking at the difference in electrical change (membrane potential, more negative on the inside of the neuron) - it then created an oscilloscope trace - it the beginning of this experiment, there is more negatives on the outside (resting potential) - then action potential: it is the movement of changed particles |
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What are the stages involved in the action potential? |
1) stimulation (this is the part of the oscilloscope trace) - resting potential is what the neuron is at when it has not been stimulated - it is at this point -70 mv because it has more - then it does + - then it starts to let the sodium in (for one 1/2 millisecond) - with the influxes of sodium ions the charge goes from being negative to positive (+40 mv) - then the potassium get moved out rapidly (-) overshoots a little bit (then it goes lower than -70mv) 2) recovery - when it goes back to the resting state (it overshoots) that is the recovery period - during recovery there is the sodium pump (it get the sodium out and the potassium back in) - this is a limit of action potential that a neruron can have, the rate of action potential is what you can control - other wise it is an all or nothing response |
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What is action potential? |
- the movement of charged particle is the action potential, after stimulation sodium rush in and the potassium leaves - the action potential is the movement of charges particles |
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How does action potential move down the axon? |
- it goes forward in a chain reaction (propagated response) - it happens in an unmyelinated axon - though in mammals many axons are myelinated - myelinated: it helps to speed the transmission - in myelinated the current jumps from one point to another (it skips from node to node in a myelin sheath) |
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What is spontaneous activity? |
- when you have an axions in a living organism you het spontaneous activity - you get a certain number of action potential even when there is no stimulation - in a cell there is a base line of action potential |
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how do you transfer information between neurons? |
- there is a little gap between one neuron and the other, this is called the synaptic gap - when the charge reaches the end of the neuron, then then release neurotransmitters - the synaptic vesicle release the neurotransmitter to the other dendrites on the other huron - the fit together in a lock and key method - this is called the postsynaptic transmission |
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What are the two kinds of neurotransmitters? |
1) Excitatory Neurotransmitter - it increase the chance that the receiver neuron will have action potential - they increase the number of action potential per second 2) inhibitory Neurotransmitter - it redoes the probability that the neuron will have an action potential
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What is an example of an excitatory Nueotransmitter? |
- an example would be ACH Acetylcholine - it is used to send a message to muscles making them contract - it is also found in black widow venom - another example of this can be Cvrave (the stuff in blow guns) - it causes paralization,it clogs up the pores so it can not get to impulse can not get to the dendrite - another example is Glutamte |
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What is an example of a inhibitory Neurotransmitter? |
- one of the most common is GABA it is related to many of the common sedatives and sleeping pills it is like valium - barbiturates are sleeping pill, they are very dangerous because you can die of an overdoes |
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what is the short had for the circuit thing? |
two prong: excitatory flat line: inhibitory |
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what is a linear Circuit? |
one neuron that is connected to another neuron you can a linear circuit of both inhibitory or excitatory neuron there can be alternation |
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what is a converging circuit? |
two or more different neurons synapses with other neurons (form a group) if you have an excitatory stimulus and an inhibitory stimulus then the cancel eachother out |
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what is psychophysics? |
- It is one of the earliest fields in psychology - it originator was Gustave fechner - he was interested in finding there relationship between the physics of stimulus (external) and (internal) psychological reactions - he looked at the absolute threshold |
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what is the absolute threshold? |
it is the smallest stimulus that you can perceive |
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what can effect you absolute threshold? |
1) smoking - it can affect your threshold for your sense of taste, it increase your threshold (you are decreasing your sensitivity) 2) alcohol - it increase your threshold for bitter things 3) Aspirin - it increase your threshold for sound, you are less sensitive to sound 4) hormones (sex) - they kind of work like neurotransmitters it reduces your threshold and increase your sense of smell, it is why when women are pregnant they have weird cravings |
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How is the absolute threshold measured? (hit there are 3 techniques) |
1) methods of limits 2) methods of adjustment 3) methods of constants |
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What is the methods of limits? explain the process. |
the experimenter presents stimuli in ascending order order which indicates the results of an experiment that measures a person's threshold for hearing a tone |
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what is the methods of adjustment? explain the process. |
that the stimulus intensity is either increased or decreased until the stimulus intensity is either increased or decreased until the stimulus can just be detected |
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What is the constant stimuli? explain the process. |
the experimenter presents 5 to 9 stimuli with different intensities in random order |
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How do you calculate the threshold for the method of constants? |
the threshold is the intensity that you perceive 50% of the time |
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What is the difference threshold? How is it measured? |
- the difference threshold is the preceded difference between the intensity of two things. It is harder to see things that have low contrast. - how you measure the difference threshold is that you have the standard (the one that stays the same) and another that is the comparison (the one that changes), you change the comparison and see if the person is accurate with the amount of change that occurred. - it can also be messed using the methods of limits and the methods of adjustment Method of constance: you measure the percentage of time that they thought that it was hevery, do this each a 100 times in order, then they look at the percentage of time that it was seen as heavier
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What can the Difference threshold sometimes be called? |
it can also be called the discrimination threshold, the just noticeable difference and the differential linas |
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What happens to people who smoke and there difference threshold? |
people who smoke have a high difference threshold for brightness, there for there need to be more contrast in order for them to see things) |
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What can mess up the difference threshold? |
Negative time error: often when you have two experiences one that is more recent that the other the other is then seen as more intense |
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What is Weber's law? |
states that the just-noticeable difference between two stimuli is proportional to the magnitude of the stimuli, (and the subject's sensitivity), i.e. if you sense a change in weight of 0.5 lbs on a 5 pound dumbbell, you ought to feel the extra pound added to a ten pound dumbbell. |
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What is the signal Detection Paradigm |
- it is a more accurate techique to see if people are perceiving the stimulus - you take one very faint intensity stimulus - then you present this stimulus only 1/2 the time - you are trying to see if the people can detect the stimulus - it all happens in random order |
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How do you interpret the results of signal detection study? |
how do you know how sensitive the observer is? (also know as d’) you takes the hit - the one where they say yes but there is nothing there in order to figure out sensitivity it is also called d prime |
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What is a response criteria? |
- Criterion is the rule for making a decision - people with liberal criterion, it does not take much evidence before they say yes - people with a conservative response criteria, they need a lot of evidence before they yes
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What is receiver operating characteristic? |
- it is way of manipulating a person criterion that if you give more rewards in one area then they will more like to become conservative, liberal or neural depending of the reward to what response |
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How do you know which person is the most sensitive to the stimulus? |
the person with 100 hits and minimal false alarms has the most sensitivity |
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What is signal detection theory? |
it is a theory about how we make the decision is we perceive things or not to see a signal from the noise |
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What are scaling studies (also called magnitude estimation)? How do they test it? |
- it used to measure hoe the perceived intensity increase above the threshold - they test it by presenting the stimulus, and then they give them a number for that intensity - you can double the physical intensity of something but a lot of the time the perceived intensity does not seem as intense - people perception are more often not correct about intensity = it is called response compression
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What is the response compression ? |
it is doubling the intensity does not make it seem twice as loud |
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What is the response expansion? |
if you double the intensity it feels way more ingest (like electric shock) |
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What is the Formula for steven's power law? |
P= KS^n p = perceived intensity K = constant S = physical intensity n = exponent |
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Log scales on graphs |
you need to use logs because you go off the graph very fast what you do is that you multiply by the same number (for the bottom bit) for compression the slope is less the one for expansion the slope is greater than one |
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What is the stimulus for vision? |
IT IS LIGHT, ELECTROMAGNETIC RADIATION |
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what are the two view about what electromagnetic radiation? |
two view: newton: he was it as particles, in particular the word photon comes that. James Clerk Maxwell: it can be more productively understood as a wave, it is a disturbance that produce a wave (ripples in a pool of water when you drop a rock) |
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What are the aspects of light that we can pick up? |
1) amplitude: the height of wave, the half way to the top, it is about the brightness of the light, so a big amplitude the brighter the light 2) Wavelength: it is the distance between one peak to another peak of the wave, it is measured in nanometers, wavelength is instituted by the visual system as colour. the longer ones is red and the shorter ones are blue if you get longer wavelength then you can see infrared (see heat), shorter wavelength you see in ultraviolet (only bugs) |
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What must the eye do to the light? |
1) Collect the light: there are number of structures in the eye that are designed to let the light in 2) focus the light: that is be use light rays by their nature diverge, this involves bending the light, they also flip the image upside down 3) Once the image is on the back of the eye on the retina, it has to signal the brain that light is there, it involves a process called transduction |
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What is the Cornea and what does it do? |
- it is the outer surface of the eye - it basically clear - it is there to let in the light - but is also there to protect the eye from the outside world - it is also there to keep everything intact, because the eye is filled with fluid and it is under pressure so it will not shift around - it also helps with the sending o the light |
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What are some of the injures that can occur on the cornea? |
- you can get disease or injury from infection or from allergies how do you know that you have this is when you start to see halos of rainbows around things or objects - astigmatism: people that are born with corneas that are not the right shape, the person loses the ability to focus some type of light and not others. The most common way is with glasses, another thing that they do it lazic vision thing. they carve the outside of the cornea |
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What is the puli? |
- the pupli is a whole where the iris is not - the pupli let light in - the puli can change size so it can control how much light can get in - it does not just respond to light level it is also controlled to the autonomic nervous system (the fight or flight responses), the sympathetic systems and the parasympathetic system (when you are relaxed) - that is when you are attracted to someone then there puli is larger, there have also been studies that found that men were more attracted to pictures of women with larger puplis that is why women is the middle ages put belladonna (made from deadly nightshade) to make their puplis dilate |
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what happens to your puli as you get older? |
as you get older your puli does not get as wide (this is called senile miosis) |
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What is the iris? |
The iris is the colour part of the eye it has a double ring of muscles, so your eyes can dilate |
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what is a disorder that is associated with the iris and the puli? |
albinism - this is a condition where there is not a lot of melanin in your skin, so the more melanin the darker you are - people with albinism do not produce enough melanin - so they do not have a lot of colour to them - it can also effect there vision, that they let in too much light, so a lot of the time people with albinism are blind |
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What is the lens? |
- it is a clear but has a yellow ting to ti - it is invoked in capturing and letting in light but it is also invoked in focusing light - it has what are called ciliary muscles that help to focus the light, it changes shape depending on how fare away the object it - as well as you get older the more layer are added to the lens - it also helps to secret out ultraviolet light, it is not very good for our eyes - the lens is soft - it also helps in accommodation |
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what is accommodation? |
it is the visual systems adapting, you are changing you lens shape so that the light is bent in certain ways in order to see |
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what are some disorders of accommodation? |
1)Myopia (nearsightedness) 2) Hyperopis (Farsighted) 2) Presbyopia |
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what is myopia? |
it is nearsightedness, you can not see things that are far away |
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what are the reason that people are nearsighted? |
there are two: 1) Axial Myopia: you are born with elongated eyeballs, so the point where the light rays coverage is in front of the retina 2) Refractive Myopia: you have normal shaped eye but the cornea is too powerful and bending the light too much |
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what are some ways to correct this? |
1) is toe wear concave glass, you are taking the light rays and they are getting border out so that it comes to the focal point at the back of the retina 2) Lask: they change the shape of the cornea so that you will see distance better |
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What is Hyperopia? |
(farsighted): they see things that are far away very well but they can not see things that are close to themthey can not bring things that are close into focus |
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what are the two resins for hyperopia? |
1)Axial Hyperopia: has to due with the shape of there eye, rather than it being perfectly round it is more flat and short 2)Refractive Hyperopia: Together the cornea and the lens can’t work enough together |
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what are some cures for hyperopia? |
Cure/ways to deal with it one way to deal is with convex glass, the go outwards, so it bend the light so it going into the back of the eye what happens when they were them is that there eye look very large you could also get lazic, still sculpting the cornea |
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what is presbyopia? |
it means old, it is an accommodation disorder that occurs with age why it happens is that the lens builds layer as they get older, and they become hard and stiff and the ciliary muscles then get weaker |
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What are some curses for presbyopia? |
then you will need to get bifocal lenses |
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what are cataracts? |
t couse the lens to become kind of milky colour so people are born with it and other develop because of eye disease or injury 75% of older people have cataracts you can not see subtle difference in brightness as well it can cause blindness |
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what is the cure for cataracts? |
one of the most common ways of dealing with them is Phacoemulsification they make a cut into the cornea and vibrates the lens very fast and the lens then falls apart and then they take it out, leaving the lens capsule, then the insert a plastic lens if they do not do this just right, they start to see ultraviolet light |
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what is the retina? |
t is the very back of the eye it is about the width of a postage stamp the photoreceptors: are right against the back of the eye, they are the most important thing when it comes to vision, they are the things they receive the light in particular they do transduction: they are the ones that are responsible for changing light into electricity they are a specialized type of neuron they have lay and lay of photochemical (they are complicated molecules) they are also called sometimes photopigments what happens when they are exposed to light is that they change colour, they go from whatever colour that they start out then becomes clear these photochemical bleach and when that happens it results in an action potential it is how the electrical signal start, this is how transduction works there are two kinds of photopigments: the rods and cons |
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rods |
they are the most frequent type of photoreceptor we have about 120 million per eye there photopigment is called rhodopsin it is kind of red it is not very good at absorbing red light there are no rods in the fovea when you get out to the periphery then it is 100% rods they are involved in seeing things in very dim light they do not give you colour, only black and white Rhodopsin takes a long time to regenerate, when you use it it then falls apart you need vitamin A in order to regenerate your photopigment |
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cones |
we only have 5 to 6 million of them per eye they are important because they give us fine detail the fovea is 100% cones they have 3 different phytochemicals: one that is good at long wavelength, one that is good at medium and the other is good as short they are for colour vision it only takes four minutes to regenerate |
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collector cells |
they collect the electrical messages from the rods and cons they are also involved in summarizing the information they are the one that take the information from the back of the eye to the back of the brain through the retinal Ganglion cells there is a 126 million rods and cons for the eye and only 1 million retinal Ganglion cells, so there has to be a lot of summery going on this is done through convergence (it is above) though convergence is different in the foveal, it is only a linear circuit that each cones have its own retinal ganglion cell, this is why you can see so much detail in contrast with the rods you have a lot of convergence, 120 rods converge to one ganglion cell this can have a good effect, that this activity comes together, summation, why they are so sensitive because you can add them up so you can have an action potential, though at the same time this is why you can not see fine detail the ganglion goes out the back of the eye in the optic nerve |
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the blind spot |
because of the way that they eye is build, that there need to be a place where the light can go out so there are no photoreceptors this is then called the blind spot we are blind there, though we typically do not notice that we have a blind spot the only way that you will be able to see the blind spot is if you cover up one eye |
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Disorders of the Retina: |
detached Retina it happens when you have a hard blow you will get a little rip in the retina the retina will liff of the back of the eye that mean that the rods and cones get separated from the pigment then thing get out of focus you can reattached it, using a probe it can cause blindness Floaters this is a substance called the virtuous hummer and it is gelly like what happens is that little bits of tissue and blood will enter the virtuous hummer |
