For this homework I would like you to go to the urls below and participate in the cow eye dissection.
You can watch the dissection or you can do your own for more class credit if you like. If you film your own dissection and post it you will get more class credit.
Watch: http://www.exploratorium.edu/learning_studio/cow_eye/step01.html
You can do your own using any eyeball you want - fish, cow, etc...
Do: http://www.exploratorium.edu/learning_studio/cow_eye/doit.html
I would the like you to post a narrative type comment in the following format: 1) briefly discuss how your text book presents the relevant information about the eye (use facts and paraphrase the material), 2) do the web activity, 3) post in a narrative format your experience with the activity, and 4) Discuss how well the web site kept its facts and figures correct in relation to the material in your text book.
(Basically I want you to spend equal time in your text book and in the web. I would like you to use the terminology they are using in the book to teach you about the eye in your post. The sort of fact check the site to make sure it is consistent with your text - I am sure they are, but you will need to discuss this. This will take some time, so be prepared to spend it on this homework).
You can turn this in before Friday - if you are going to use a real eye I'll give you more time.
Let me know if you have any questions,
--Dr. M
The Goldstein text outlines the process by which vision begins in the eye. This text describes how reflected light is focused into an image within the eye which is transformed into electrical signals at receptor sites (Goldstein,2007).
Additionally, the text diagrams the eye showing how the lens and cornea focus the image onto the retina (in the back of the eye) where the light works upon the receptors to transfer the stimuli. This information is processed through light sensitive chemicals on the rods and cones, and the information then flows through the optic nerve for mental processing (Goldstein, 2007).
While I am seriously considering attempting to obtain a cows eye and disect it myself, I decided it best to complete this activity in the simplest format in case I chicken out (er...have a cow about it?).
After my children were all (both) snug in their beds, I was able to luxuriate in having the couch all to myself, offering me the requisite quiet and solitude to give this activity the attention it deserves. I worked through the images, descriptions and videos on the link. I watched with an open mind, and was fascinated by what I saw. As I went through the various stages of the web video dissection, I was most surprised at how the lens looks when removed from the eye structure, and that it actually resembles a magnifying glass! Also, I finally understand what a blind spot is - it where the retina attaches to the optic nerve, and so it lacks light sensitive cells!
This site signifigantly altered my understanding of the anatomy and function of the eye. I must say, prior to this I tended to think of the eye as a whole without giving much thought to the individual parts and purposes - and no textbook had helped me imagine beyond that basic understanding. (http://www.exploratorium.edu/learning_studio/cow_eye/index.html, 2009).
In conclusion, the book provided a helpful review in a basic sense, and a good cross-reference with compatible information which was accurate in both sources, as far as I am aware. However; the process of viewing the web site with the eye dissection was much more pertinent and helpful to my personal interest and comprhension of this particular topic than any book could be for me.
1) The S&P book I have is Goldsteins 4th edition. When discussing the eye he goes in the same basics as the dissection video. Starting with the cornea, pupil, lens, retina, and then talks more about the rod and cones. The book also talks about bipolar, horizontal, amacrine, and ganglion cells. The book shows an image of how light enters the eye and the stages it goes through. Goldstein goes on to describe how the eye focuses light to create an image by comparing it to a camera.
2,3) I have to say that the web activity was really cool. I thought I might get a bit grossed out but after growing up on a farm and delivering baby sheep and goats this was nothing. The animal blood and things don't bother me but human blood makes me sick. I've dissected frogs and pigs before but never an eye. I was really suprised that we could see everything. I knew the eye had a lot of different parts but I never though I could see them so clearly like in the video. After watching the video I want to go home and dissect a pig eye.(don't worry I live on a hog farm)
4)The video did a very good job explaining the parts of the eye. The book goes more in depth using all the science terms about receptors and transduction and pigments to describe the functions but the images aren't the greatest. The video really showed us what the parts looked like and explained things in plain english so we could understand it. I was also suprised by the blind spot being a long fiber. I took biopsych and never really knew what it looked like. I only knew what it was and where it was not it's structure. I definately learned more watching the video than if I would have just read the book.
1) The basic information about the eye is present in Chapter 3 of Margaret W. Matlin and Hugh J. Foley's Sensation and Perception book, The fourth Edition. They begin by describing the structure and function of the eye. They explain how our eyes (and all of our sensory organs) serve as Transducer, which is the process of converting one form of energy into another. The describe how the eyeball is a slightly flattened sphere, the cornea is located in the front of our eye and is the outer layer that protects it, which you can see by looking at someone's eye from the side. Then cornea takes in the light and helps to bend the light ray so it hits the back of the eyeball, where the the light is brought in to focus. The Iris is used to restrict the amount of incoming light. The pupil is the hole in the middle of the iris where the light information passes. The lens and retina and all of the above parts of the eye work together to decipher the light that is coming in, whether they are restricting the light, or the passage that the light passes through, they all work together. The book also describes rods and cones, and shows a picture of the eye structure.
2 &3) When I heard we had to watch the dissection of a cow's eye I was thoroughly grossed out. As I sat down to watch the dissection I was preparing myself for the worst. However,after watching the dissection I found that it wasn't that disgusting at all, and it was really interesting. I have lived in a small town in Iowa my whole life, and my good friend lives on a farm where their main job is raising cows, and now I feel like I might want to dissect a cows eye myself :S. I'll probably chicken out when I put it in my hand but I'm going to try.
4)The text and the video went together fairly well. They stated all of the same facts, and went over all of the same things. The book goes more into depth than the video does, but the book uses more confusing terms and words it in more confusing ways than the video did. I found that watching the video was more helpful than reading the text, and a lot more interesting!
In my text, the authors begin the section on the eye with it's structure. This begins with the cornea, the first tissue light encounters. The cornea is transparent and most light passes directly through it because there is no blood or vessels. Directly behind the cornea is the aqueous humor, a fluid that is derived from blood and supplies nutrients and removes waste from the eye. The book then details the crystalline lens as containing no blood to remain completely transparent. However, light must first pass through the pupil, which is simply a hole in the muscular structure, the iris. The iris will expand and contract to ensure the proper amount of light is allowed into the eye. The iris is also responsible for the eye's 'color.' Light is then reflected a fourth and final time by the eye's vitreous humor, which is a clear, gel-like substance taking up 80% of the internal volume of the eye. Finally, the light is brought into focus by the retina, which detects light and relays the visual message to our brain.
The video of the dissection was gross but interesting. I do remember dissecting a cow's eye in about 8th grade, however, I'm glad this assignment was only to watch the dissection rather than have to actually cut into one. The video was somewhat brief in detail when compared to the text, however it was very accurate. The video listed all parts of the eye (Cornea, aqueous humor, pupil, iris, vitreous humor, lens, and retina) and even included some parts that the book did not discuss (optic nerve, tapetum). One benefit of the video is that it makes learning the eye's anatomy a little more tangible and gives you a clear picture of the structure of the different tissues that complete the eye. An animated diagram in the text does no such justice to the actual structure. The video also does a nice job of comparing the cow's eye to a human eye, including differences in muscle tissue, lens shape, and a structure at the back of the eye called a tapetum, which humans do not have.
My text book begins discussing the eye by first defining it as the organ by means of which we gain visual access to the world. The definition is followed by a diagram of the eye including the retina, pupil, lens and the optic nerve and these parts are also described. The text then goes on to explain vision saying that specialized neurons in the retina of the eye receive light and cause neural signals to be generated and then transmitted to the posterior portion of the brain.
As I watched the video in the Union computer lab, I'm sure I got some looks from people wondering why I was making faces at the monitor. The video completely grossed me out but it was so interesting at the same time. As I was taken through the dissection of the cow eye, I found myself fascinated by how many parts there actually are in the eye. Reading about it is one thing but actually seeing it is very clarifying. Everything in the eye has a specific purpose; even things that I thought just looked like gross goop. I especially was interested in the tapetum which reflects light from the back of the eye. I had no idea that is why my cat's eyes glow in the dark.
The text did a fairly good job at defining the parts of the eye but I understood the video so much easier. I think it is much easier to learn something if you can see it. Also, the video was much more captivating than the text. I felt like there was more relevant information in the video than in the text. I may just feel that way because I was more interested in the video but overall, I think the video did a better job of explaining the eye than my text did.
1)The Goldstein textbook starts behind the website. It begins where vision begins in the eye. Which is in the retina which lines the back of the eye and contains the receptors for vision. The cornea and lens create a focused image on the retina. Then rods and cones contain visual pigments Which react to light and trigger signals. These signals are sent to the optic nerve which sends signals towards the brain.
3)I could not get the videos to work but I have done this exercise in the past with an actual cow's eye so it was a good reminder to read through the steps and the terms. I am however glad I did not have to hear the sound of the cornea being cut because I know that it sounds really gross! I do think the most interesting part of this was the tapetum. I wonder if that is how someone got the idea for reflectors for bikes....
4) I do think that the book had the same termonology however I thought it was much easier to understand coming from the examples even if I could not watch the videos it was a much easier read.
My text goes through the anatomy of an eyeball listing the various parts and their functions. There's a very good diagram of the rods/ cones and receptors all the way back to the optic nerve fibers. This helps a bit with understanding the path the visual input follows, and there is also a diagram of the brain with the eyes situated in their place which traces the path the optic nerves take to the visual cortex. I thought that was interesting.
The video was not quite as repulsive as I initially thought it was going to be. As a junior in high school I had the opportunity to do a virtual cow eye dissection for my psychology course, but it was ten years ago and was a computer generated image... in other words, no vitreous humor to splooge out. The subject matter was nothing new, but using an actual eye was a whole new experience. I'm glad for the option to watch someone else do the dissection, it made it easier to enjoy the learning and not get queasy touching the actual eye.
I didn't find anything inaccurate in the video, and I do agree with the others who posted that they felt the video made it easier to understand the parts and terms. I think seeing the eye as a whole and then the dissection process gives a perspective on how the parts fit and function together in the real world, not a pretty diagram. plus, some of those images and sounds will be forever burned into my memories. What a fantastic way to learn eye anatomy.
1) The textbook that I chose was Goldstein's sixth edition of Sensation and Perception. He discusses different parts of the eye including the cornea, iris, and pupil, as well as rods and cones,and different cells that are important with sight,such as retinal cells. He also refers to the blind spot, which is where the retina is attached to the back of the eye.
3) Although I could not get the videos to work for me, the photos and discriptions of the eye were pretty intense. I found it interesting how they were showing the lens as a magnify glass, because I remember as a child watching my grandpa use one all the time and it's need that the lens of our eyes can do the same thing. Overall, the pictures and discriptions were helpful in learning how the eye is made up.
4) I though that overall the textbook had a lot of great information and terminology throughout the chapters, but the website was much easier and quicker to follow and get the point of how the eye is made up and what each of the main parts is used for. It was also very helpful seeing the photos of a actual cow's eye to compare to other animals or a humans.
1) The textbook that I have is Goldstein's sixth edition Sensation and Perception book. In the textbook, Goldstein discusses similar details of the construction of the eye. He talks about the anatomy of the eye and how messages are transferred to the brain, much like the cow dissection video did. When Goldstein was discussing the eye, itself, he used many terms that were similar to what the video used such as; sclera, cornea, pupil, iris etc.
3) I really like this activiy. In high school biology we dissected a sheep's eye and doing this activity brought back memories and things that I learned while dissecting that eye. However; doing this activity I felt I had a better understanding the second time around rather than the first. Also, this activity seemed to go into more detail than I remember going into when I dissected the sheep's eye.
4) As I mentioned before, much of the material that was presented in the video correlated closely to what Goldstein discussed in his textbook. The terminology was similar to the textbook and also Goldsteins discription of the eye and how it transferred messages to the brain was simliar to what the web site described. I thought it was much easier to understand the web site just because it had actual pictures of what was taking place adn it was less technical and more interesting than what the textbook described.
#1. In my textbook the author begins the chapter on the anatomy of the vertebrate eye. He begins by saying that eyes of all the vertebrates; from fish to mammals, have one thing in common and that is they all possess a layer in the eye called the retina. He then starts to explains the different parts of the eye and describes what each section is (retina, lens, cornea, etc).
#3. The activity was very interesting. I have never seen the inside of an eye of anything. So it was very neat to see what it really looked like. It was almost pretty...which I never would have thought would be a word to describe it. The eye is such a small thing, so for it to be dissected apart and to see the little pieces break apart and then hear what each was used for was enlightening.
#4. The website broke the parts of the eye down which made it very clear what each part was used for and looked like. The book kept things in a more proper language and therefore didn't break the terms down. But the meanings of the terms according to the book vs. the website were the same, just more technical in the book.
-I always knew that we saw things right-side-up, but that the lens did that for us. IN the video when you saw the lens taken out of the eye and everything was upside down, it blew my mind. It's one thing to have that knowledge and know that it is just that way, but a completely different thing to actually see it. It was absolutely amazing and that was probably the highlight of the video/dissection for me. Fascinating!
1.)The textbook that I bought is Goldstein's sixth edition of Sensation and Perception. Goldstein talks about the perceptual process of the eye which explains how specific structures are involved in focusing the image, transduction, and neural processing. Goldstein also talks about light and how it is a stimulus for vision, because being able to see involves a stimulus which is light.
3.)The video was very interesting, but kind of gross at the same time. I ususally don't get very grossed out because I grew up on a farm and I have seen much worse things than that. I think just the fact that our eye has so many parts to it, which are all slimy and weird looking, is why it was a little less fun for me. Overall, it was a good video that was very informative, especially since we are studying sensation and perception!!
4.) The video was a huge help to better understand the parts of the eye and what their functions are. Actually seeing the eye and watching it being disected part by part was very helpful and quite extraordinary. The book that i'm reading used the same vocabulary words like the video such as the retina, cornia iris, pupil, but these words were much better understood by the video.
In the Goldstein, E. B., (2007) Sensation & Perception, 7, 25-59, 195-213, it talks about the movement of the eyes. The real movement is based on real movement, and apparent movement is based on what we perceive is moving like when we watch a movie we may see a car move. In chapter 2 in the text, it covers the eye, and how perception; how visible light that we see that measures between 400-700 nm on the electromagnetic spectrum and is photoreceptor sensitive to the rods and the cones. The image of in the right eye is transferred to the left side of the brain, and vice versa for the left. The image in which we see is then goes through the cornea then lens which is a biconvex that allows detailed focusing of light to the retina; thus making the image what we see inverting the image as it goes though the posterior segment that contains vitreous fluid that travels to the cons and the rods that then connects to the optic disc and travel to the optic nerve sending a neurological through the axons of the ganglion cells then sending impulses messages to the left and right side of the brain that is shaped like and (X) in the cerebral cortex. The eye has 6 different muscles that allow it to have movement. The lateral rectus helps move the eyes laterally, the medial rectus moves the eye medially, the superior rectus elevates the eye and turns it medially, the inferior rectus depresses the eye and helps turn it medially, the inferior oblique elevates the eye and helps turns it laterally, and the last muscle is the superior oblique muscle helps in depressing the eye and helps it turn laterally according to Hoehn, K. & Marieb, N.E., 2007, 7, 557-578. With that in mind as the light increase the sphincter papillae muscle helps in the constriction of the eye which is located in the iris, and the dilator papillae muscle increase the pupil size from a better view such as if we were put into the flight or fight mode. As the signal transfer through the optic nerve sends the single to the occipital lobe and the visual receiving cortex.
The experience of watching the short film on the dissection is something that doesn’t really grouse me out. The reason why, is that I have seen it before in anatomy class; as well as having to dissect one in class. The thing that was interesting is trying to find and eye to film a dissection, I went to Hy-Vee, Fareway, and too a meat market in Waterloo, there facial reactions were funny when I asked for and eye; then I had to explain what I needed it for they changed.
The Goldstein (s&p 2007) textbook starts talking about where vision begins in the eye; the retina (which lines the back of the eye and contains the receptors for vision), the cornea and lens (creates a focused image on the retina), and the rods and cones (that contain visual pigments which react to light and trigger signals). These signals are sent to the optic nerve which then sends the same information to the brain.
I have done this exercise in high school with a cows eye and a lamb eye. I recognized the terms and steps from when I did it in the past from the video. I felt I had a better understanding the second time around rather than the first. It seemed like when I did it the first time, we did not know what we were doing because we could not hear or see the teacher demonstrating certain parts of the eye.
A lot of the material that was indicated in the video was similar to what Goldstein discussed in the textbook. Goldsteins explanation and description of the eye and signals messages to the brain was simliar to what the video indicated. I enjoyed the video, I just wish it was another animal eye that I have not dissected before.
1. I have the book sensation and perception by Jeremy Wolfe. The textbook starts elaborating on some keys aspects of light physics. A Few terms were important in this section such as wave of photons and absorbed and reflected light. Wave- is an oscillation that moves through a medium by transferring energy from one particle to another without displacing the medium. Absorbing light was another term I thought to be essential in the discussion of the eye. The book states that this is to soak up light noise and energy without transmitting it. Reflection is when your eye redirects something that strikes the surface especially light sound or heat. Then the book shows a strait forward accurate description of the eye which shows the full anatomy. It shows good examples and figures to illustrate the various pieces of the eye. It spent some time on the retina by saying that this part of the eye is essential because it has to receive images from the lens and send it to the brain. In looking at the responsibilities of the lens, it is said that it changes the focal points inside the eye.
2&3. In participating in this activity, I was have to say that it turned my stomach a little bit but it was alright once I saw what was inside of the eye. I didn’t like the fact that she didn’t wear any gloves when doing this and she said that she does about four a week. When doing this activity in your office, I had to hold my stomach in because I was a few seconds from letting by body produce its natural defense mechanism. You and I watched that he/she take that eye completely apart and show us certain parts of the eye that were essential in vision. The best part was when she took the scalpel and cut into the eye which squirted out a lot of the nucleus. Also another highlight was when she pulled out the iris during the dissection. Despite the nasty parts of the dissection, I learned a lot about the different parts and functions of the eye and the purposes in which their used. I think that this was a beneficial activity because it let you get up close and personal with the eye instead of just reading the terminology in a book.
4. The website did actually a better job describing the anatomy of the eye. Also it did a better job breaking down the what the various parts of the eye were used for. The textbook did the same thing, but it was a little harder to understand with the phrasing it used to describe the eye. The text took the information a little further than the website by looking at retinal informational processing, light transduction by rods and photoreceptor. The website mentioned the optic nerve as a carrier of messages through the retina to the brain. My textbook really didn’t elaborate on that much basically showing a picture of where it was located in the eye. There was more terminology in the text that elaborated on many different parts of the eye versus the website. The website site hit on all the main functions and parts which were very consistent with the text material. I prefer the website because it was strait forward and was easier to understand the information. Overall the website had the same information as the text with minor terminology differences.
1) The textbook describes all the elements that make vision possible including the different eye structures and parts of the brain. It also explains how they each interact with light in a very detailed way. It first talks about the focusing elements of the eye through where the light goes in which are the cornea and the lens. When an image is created in the retina, the light in this image stimulates the rods and cones receptors that are located in the peripheral retina. The only part of this structure that has no receptors is the area where cells fibers stream out of the eye to form the optic nerve. These stimulated receptors trigger electrical signals that flow through a network of neurons to the optic nerve, and then they are conducted to the lateral geniculate nucleus in the thalamus to finally arrive at the visual receiving area in occipital lobe of the cortex. In the remaining of the chapter, the textbook talks in detail about the visual receptors and neural processing.
2,3) I remember when in high school having to dissect a cow’s eye. It was a group assignment and I was the one in charge of getting the eye. I don’t remember learning much about it but I do remember it was an interesting and disgusting experience. While watching the video, besides being grossed out I also had several flashbacks of me touching that icky stuff in that lab session in 9th grade. I didn’t do so bad this time because I didn’t close my eyes or skip any part of the video, and I also remember a lot of the eye’s structures and their function shown in the website.
4) The website had a more detailed picture of an eye than the textbook. It also explained thoroughly the several eye’s structures and their function. I think the video had a stronger impact than the textbook because while watching the dissection step by step, it was like I was participating in it. In general, the material, the definitions, and some of the pictures in the textbook were similar to the website. However, the textbook talked more in detail about the whole structure of the visual system beyond just the eye.
1) Our text gives a fairly basic and brief rundown of the various components of the eye. Pictures help to show how light passes through the cornea, may or may not be focused more as it passes through the lens, before coming to rest on the fovea, our blind spot, at the back of the retina. It also emphasizes the message from Visual Intelligence that the objects do not, of course, enter our eyes but only reflected light particles which are constructed into a 2D image on the retina, before it is then constructed back into 3D in our brains. Goldstein spends considerable more time talking about the rods and cones, and exactly how light comes to fall on our fovea. Basically muscles will contract to increase or decrease the thickness of the lens in order to focus the various light rays reflected off of the object onto the fovea.
2) The web activity was awesome. I think I’ll have to get a hold of a cow eye and try this out. When they popped the lens out and used it on the newspaper I almost didn’t believe it was real. Seriously? Next time I have a cow nearby but no magnifying glass for miles I’ll know what to do.
3) When you read about the eye it really just sounds far too complex to even begin to understand. Our own vision just seems too flawless and complicated to be governed by the same basic rules which govern binoculars, microscopes, telescopes, and reading glasses. However, this video helps to demonstrate why it probably is that so many people who study consciousness begin with advanced descriptions and examples from visual psychology. As much as it might SEEM to be totally mysterious it isn’t. When evolution first began to take hold, the human eye was thought to be one counter-example. Clearly something so complex could not have developed on its own. To see this cow eye, with hunks of tissue and muscle for movement and control, runny protein-water for shape and stability (aqueous and vitreous humor), and an actual lens, that can be cut out and used on its own as a magnifying glass, for me completely demystified the human eye. Not to say that it made the human eye less interesting, more so in fact.
I now have a much better understanding of how the eye works, and of the various structures and their functions. Originally the eye just appeared as this mass of red, white, and blue colored tissues. How can vision possible come out the back end? Seeing how the various simple components are all organized logically from front to back with the specific purpose of focusing light rays down to an incredibly tiny spot at the back of the eye (in animals even reflecting the rest back out by way of the tapetum covering the back of the eye), to be transduced into electrical impulses and sent to the brain, gave me a very broad macro-level understanding of vision that you really can’t get in any other way than tearing the thing apart and looking at it.
4) The website and the book didn’t disagree on any facts or figures that I recognized, but simply focused on different specific area’s. Both had in common the very basic structures in the eye, viz. cornea, lens, retina, fovea, optic nerve. Although not discussed in the video, the online PDF did discuss the significance of rod’s and cones. And naturally, since the video was not designed to discuss any of the more advanced psychological issues involved in sensation and perception they spent more time discussing the iris, pupil, and the tapetum (in animals since it was cow eye). The text spent considerably less time discussing the aqueous and vitreous humor as well.
The textbook discuss a lot about anatomy of eye, especially chapter 3. There are many good illustration that can help in better understand the whole process of seeing. The author talks also about eye interaction with the light.
The video was interesting. I have never seen an cow's eye before like that. Cows have very similar eyes to human but just the different is that they are bigger so it is easier to do dissection on cow's eyes.
From the video and the activity one thing that is important that we see things right side - up. I have never see n that before and I have to say that it was not "pretty" at all yet very fascinating.