CSEC - The eye and how it works

How the eyes adapt to different light intensities

Too much light would damage the receptor cells in the retina. Too little light wouldn't allow them to work properly.

The iris contains a pigment that gives our eyes their nice colour, this protects the retina from getting too much light. A darker iris colour gives more protection. But that isn't flexible enough to cope with constant changes in light intensity.

Instead, there is yet another reflex!

The iris contains two sets of muscles

One muscle is radial, arranged round the pupil like spokes in a wheel.

The other is circular, arranged concentric rings around the pupil.

When there is too much light, the pupil is closed down by contracting the circular muscle.

When there isn't enough light, the radial muscles in the iris contract, pulling the pupil wider. This lets more light through to the retina.

Each iris has both circular and radial muscles in it at the same time. Have a look in a mirror, or at your friend's eye - much more fun!

Adapting to different objects - Accommodation

The eye also has to adapt to be able to focus a clear image of an object no matter how far away it is from the eye. Again, this is under the control of the nervous system.

When the eye looks at an object that is far away the ciliary muscle pulls on the suspensory ligaments. These pull on the lens and make it flatter (less convex). This brings the rays of light from the object into crisp focus on the retina.

But with an object closer to the eye, the lens needs to be more convex (fatter). To do this, the ciliary muscles relax to allow the rubbery lens to return to its naturally rounder shape.

The brain's careful control of the ciliary muscles allow it to adjust the convexity of the lens to give a perfectly focussed image on the retina.

This retinal image is not the same as the object that is being looked at. The image is inverted.

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CSEC - The Eye - functions of the various parts

THE EYE

Learn the part of the eye and the function of each part.

Parts of the eye	Function
Cornea	This dome-shaped layer protects your eye from elements that could cause damage to the inner parts of the eye.
Sclera	This is a smooth, white layer on the outside. The sclera provides structure and safety for the inner workings of the eye, but is also flexible so that the eye can move to seek out objects as necessary.
Pupil	The pupil appears as a black dot in the middle of the eye. This black area is actually a hole that takes in light so the eye can focus on the objects in front of it.
Iris	The iris is the area of the eye that contains the pigment which gives the eye its colour. This area surrounds the pupil, and uses muscles to widen or close the pupil. This allows the eye to take in more or less light
Lens	The lens sits directly behind the pupil. This is a clear layer that focuses the light the pupil takes in. It is held in place by the ciliary muscles, which allow the lens to change shape depending on the amount of light that hits it so it can be properly focused.
Retina	The light focuses by the lens will be transmitted onto the retina. This is made of rods and cones, and is connected to the optic nerves that will transmit the images the eye sees to the brain so they can be interpreted.
Ciliary Body	Ciliary body is a ring-shaped tissue which holds and controls the movement of the eye lens, and thus, it helps to control the shape of the lens.
Choroid	The choroid lies between the retina and the sclera, which provides blood supply to the eye, to gives nutrition
Vitreous Humour	The vitreous humour is the gel located in the back of the eye which helps it hold its shape.
Aqueous Humour	The aqueous humour is a watery substance that fills the eye which allows the eye to maintain its shape. If a patient's aqueous humour is not draining properly, they can develop glaucoma.
Fovea	an indentation in the centre of the retina. This small part of our retina is responsible for our highest visual acuity
suspensory ligament	the ring of tissue which holds the lens in place

Lets see how you do when you try to label the L.S. of the eye. (DO NOT CHEAT NOW ;) )

DONT know HOW to STUDY?...get help here.............

How to Revise

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• The aim of the information presented here is not to provide a rigid guideline for revising.
• The fact that you are already here suggests that you have an effective revising strategy.
• The information offers a collection of hints, tips and strategies that you may or may not be aware of.
• It is up to you whether you use them or not.
• Remember that whatever works for you is best.

• Preparing to Revise
• Time Management for Revision
• A Suitable Environment
• Revision Techniques:
  • Mind Mapping
  • Mnemonics
  • Using Past Papers to Revise
• Advice from Other Students
• Strategies to Avoid

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Preparing to Revise

Before you start revising you must know what exams you have:

• How Many
• When
• Where
• What Time
• Format

Make sure you have the following:
Course Information	Study Aids
Notes Textbooks Completed Assignments Course Notes Past Exam Papers	Folders Dividers Plastic Wallets Highlighters Coloured Pens and Pencils A3/Coloured Paper Index Cards?

• It will be easier to get all the resources you need to revise well before you start.
• It will be easier if you organise and update your notes throughout the year.
• If you haven't done this, spend one evening organising and ordering everything you have.
• You must have a complete set of notes to revise from. Revision is about revising, not learning.
• Go to all revision lectures and seminars, this may help you to identify central questions and subject patterns.
• Ensure that you find out what the key issues and concepts are.

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Time Management for Revision

Revision Timetable

• Use a revision timetable. Follow this link to a revision timetable you can print out.
• Use the timetable to structure your revision.
• Fill in your own study times in the spaces along the top of the timetable.
• Alternatively, make your own timetable, use a diary or wall-chart that is specific to you.
• Use the timetable provided as a guide if you don't know what to do.
• Some people like to study early in the day, others prefer to study later on.

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Tips for Time Management

• Do not intend to study all day.
   
• Schedule breaks in your working day for fun, food, relaxation and exercise, but not all at once (IMPORTANT).
   
• Too much work can be as unproductive as too little work.
   
• A good way to start is to work for 50 minutes, then have a 10 minute break every hour.
   
• Try to give each subject equal time, do not concentrate on one subject at the expense of another.
   
• Do difficult tasks at times when you are at your most productive.
   
• Be realistic - don't plan a schedule you can't manage.
   
• Be disciplined - stick to what you say you will do.
   
• Be flexible - you never know when an emergency will crop up.
   
• Leave time at the end for reviewing what you have done and what you must still do.
   
• Reward yourself when you achieve targets or goals.
   
• Don't try to do all of the hardest topics at once. Spread them around evenly with the easier ones.

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A Suitable Environment

Your study environment should be:	Your study environment should contain:
Calm and quiet Well lit A good temperature Full of nice, fresh air to keep you awake Free from distraction (i.e. mobile phone, girlfriend, boyfriend, TV, alcohol etc.)	Large table or desk A good chair A dictionary and thesaurus Stationary and other study aids (as above) Course information (as above) A drink or perhaps something to nibble on while you study.

• It is important to work in a comfortable environment.
• A good way to learn is by association - the place in which you study can be a useful cue to recalling information.
• It is hard to study in your bedroom every day.
• Try thinking of other places to study. Anywhere will do:
  • Libraries
  • Museums
  • Galleries
  • Gardens
  • Friends' houses
• Anywhere you think you will be able to study could be worth trying.
• Although it probably isn't possible, the ideal way to use your environment as a revision technique would be to revise each topic in a different setting.

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Revision Techniques

• Revision should be as active as possible.
• The best way to do this is to take the information you have and put it into a different format.
• You should also try to use as many different parts of your brain as possible while revising. For example, writing something in bright colours gives you a better chance of remembering something than if you write it in black because you are stimulating the part of your brain that deals with colour as well as written information.

Mind Mapping

• If you didn't already know, a mind map is a kind of advanced spider diagram that makes good use of pictures, colours and spatial relations.
• Mind maps increase your chances of learning a subject because they stimulate multiple parts of your brain.
• A mind map that is constructed with thought and care will be a much more effective learning method than a simple page of notes or a simple spider diagram.
• Mind maps are easy to construct.
• You should be as imaginative as possible when you are constructing a mind map.

Mind Mapping - Step by Step

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STAGE ONEThe first stage involves putting a title in bold, capital letters in the centre of your page. Although this example does not use pictures, it is best to use some kind of picture to help with recall of information. This example is not perfect. To increase effectiveness, mind maps should preferably include: Pictures Colour Memorable words / cues to memory

STAGE TWOThe next stage involves adding main branches to your diagram that represent each of the areas of the topic being studied, or its related topics. The branches should extend far enough from your central image to avoid over-crowding the page and confusing information. Ideally, pictures should be used to represent themes and concepts. It helps if the branches are different colours and/or shapes. The branches should be: Bold Bright Colourful Labelled memorably and clearly, preferably in colour (not shown in this example). You should include as many aids to recall, such as pictures and key words, as you can.

STAGE THREE The next stage involves adding sub-branches to your hierarchical diagram. These branches are also coloured. You may find it helpful to use different shades of the colour used for the main branches. Continue to label in bold, colourful lettering. Continue using simple images to represent concepts and to make sense of your mind map. Your completed mind - map or diagram should be: Bright Colourful Visually bold Aesthetically pleasing Ordered Meaningful to you Inclusive of Inter-relationships between headings / topics

• As you can probably tell from this crudely drawn example, mind-maps are best drawn by hand.
• You do not have to follow this example. This is just a framework to build your mind maps around.
• Mind maps are made to your specifications. They can be as simple or as complex as you want them to be.
• Different subjects or topics will require different layouts.
• Mind maps should look individual to aid your recall of information.

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Mnemonics

If you were trying to teach yourself the colours of the visible spectrum, you would probably have a list and a picture like this somewhere on your mind map:

Red Orange Yellow Green Blue Indigo Violet

You may have noticed that the first letter of each word on the list has been highlighted. If you take each of these letters and place them in order you get a word that you can read:
ROYGBIV

This is not always the case with lists of words. You may need to rearrange the first letters to make yourself a word or phrase like this:
BOY VIRG

The most important thing is that it is meaningful to you and that you remember it.

In the exam you could write the word or phrase on a piece of paper and then fill in the gaps like so:

B lue O range Y ellow V iolet I ndigo R ed G reen

In cases like these, it is sometimes better not to do this, as there is a certain order in which the list must be remembered.

A good way to overcome this problem is to make a sentence with words beginning with the first letter of each word:
Rampant Owls Yelled Give Back Ian's Video

It is almost certain that you could do better than the examples shown. Please try.

This technique is recommended by 'Memory Master' Dominic O'Brien.

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Using Past Papers to Revise

• Passing exams is as much about technique as it is about knowledge.
• You need to practice your timing as well as your recall of knowledge.
   
• To start with, compare the notes you have against the questions asked on your past papers.
• Make sure you have enough material to be able to answer all the questions.

Answering Questions
Stage 1.

• Go through the paper attempting all questions using notes and books to help you.
• If you do this early enough you will have time to seek help with anything you don't understand, or find confusing.
• Amend and highlight your notes in accordance with your performance.
• Repeat.

Stage 2.

• Go through a paper in exam conditions.
• Build yourself up to going flat out for up to 3 hours. It's a big strain mentally and physically
• Afterwards, go back through and make extra notes on anything you still find difficult.
• If you are short of time when revising for essay-type questions, practice making essay plans instead. These are beneficial in that there is a greater chance of a teacher giving you feedback on a plan than on a whole essay.

Stage 3.

• If you still want to do more work, analyze your own answer in terms of:
  • Content
  • Structure
  • Expression
  • Relevance
•  Go back through attempted papers and try to improve your answers by:
  • Editing
  • Filling gaps
  • Correcting errors of fact
  • Correcting errors of misunderstanding
• Reduce each essay you have done to note / plan form and compare it with the original plan you made.
• Examine and discuss answers to past papers with others to better your knowledge and understanding.

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Advice from Other Students

• Here is a collection of strategies that other students use.
• You may find it helpful to try a couple of these techniques, you never know what will work until you try.

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"I just brainstorm everything I know onto one piece of paper over and over again. Then I go back through my notes to see what I missed. Whatever I haven't put down is what I don't know, or won't be able to remember in the exam. Then I just learn that."

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"I like to work with other people. I find that if I can explain something to someone else, then I know it and understand it. And if you revise with other people they might teach you something you didn't know or had forgotten about. It's dead handy like. You can even test each other."

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"I write down everything I know about the topic I'm revising by using all the books, notes and all that sort of stuff. Then, I redo the notes I've made again and again, reducing them each time until I only have one page of notes to revise from."

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"I like to use mind-maps and diagrams to help me learn. Visual memory is the best! I'm also a big fan of saying what I'm learning out loud. In fact, the more different ways you can think of that put the information through your brain, the better. My favourites include reading, singing and drawing."

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"I make mnemonics. You know, like when you take a letter of each thing you want to learn and make a word or a story from it. Did you know that World Memory Champion Dominic O'Brien uses this technique to memorize things?"

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"I like to practice before the big event. Getting all the past papers and doing questions from them helps. It isn't just knowledge you have to worry about in exams, it's exam technique and style as well. If there aren't any past papers or anything, I make up my own questions. You have to use your imagination sometimes, and there is no point knowing everything and not being able to apply it."

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" If I can summarise each topic it means I have quite a good idea of what is going on. If not, it means that I still have work to do."

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Strategies to be Avoided

Here is another collection of advice that other students have given. These strategies are not helpful. If you hear anyone saying they are using them, do not be fooled into using them yourself. They do not work.

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"I record the lectures that I attend on my dictaphone. If I play them to myself while I sleep, they'll sink in and I won't have to do any work while I'm awake. Am I clever or what?"

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"Cramming. Cram cram cram cram cram cram cram cram cram cram cram cram cram  cram cram cram cram cram."

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"I put my notes under my pillow at night and by the time I've woken, the answers have floated up into my head."

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"I work all day every day. There's no time for breaks at exam time. That's what I've always said."

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"I find that if I leave my revision as long as possible, it makes me panic so badly that I do everything really quickly and save myself loads of time."

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"I just revise a few topics from each subject. I'm a lucky guy, There's always something I can answer when I do that."

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"Revise? I don't have to revise, I remember it all the first time round, and if I can't remember, then it's not worth knowing."

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The most important points to remember when you revise are:

Start early, the earlier the better. Revise don't learn. Be organised, make a timetable. Revise where you are most comfortable. Use techniques that are the best for you.

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