1. Human Sense Organ
- the eye

2. WALT know the structure of the human eye
Source : Diagram resources, Human Anatomy and Science Diagram

3. Task : Look at your eye diagram and label it based on the picture shown to you.
A - Lens
B – Conjunctiva
C – Cornea
D – Iris
E – Pupil
F – Aqueous humor
G – Sclera
H – Choroid
I – Retina
J – Fovea
K – Optic nerve
L – Vitreous humor
Do you know any of the names in German?

4. Vocabulary Lens – Linse Iris – Iris Cornea – Hornhaut Pupil – Pupille
Ciliary body/muscles – Ringmuskel
Suspensory ligaments - Linsenbänder
Scelera - Lederhaut
Choroid – Aderhaut
Retina – Netzhaut
Fovea – Sehgrube (gelber Fleck)
Blind spot – Blinder Fleck
Optic nerve – Sehnerv
Vitreous humour – Glaskörper
Aqueous humour - Augenkammer
Task : Group work - Match the funtion to the structure. Copy into folders.

5. Recap : match the structure to its correct function!
1. Retina
a. Aperture of the eye which controls the amount of light that enters the eye.
2. Iris
b. The bundles of nerves that takes nerve impulse from the retina to the brain.
3. Pupil
c. Coloured structure that controls the size of the pupil.
4. Fovea
d. Area of the retina with the most detailed vision.
5. Optic nerve
e. The tough, outer coating that makes up the white of the eye.
6. Sclera
f. The anterior part of the sclera which allows light to pass through onto the lens, where it is refracted onto the retina.
7. Cornea
g. Layer containing the rods and cones, which helps
see light and colour.

6. WALT know how the retina functions.
Source :

7. Source : http://webvision. med. utah

8. Eye shown from above:
Microscopic pictures of the retina show that there are two types of photoreceptors:
cones and rods.
If you look at different zones of the retina (A-E) you can see differences. (A=E, B=D)
Cones (Zapfen)
Rods (Stäbchen)
Interpretation – A,E have lots of rods, B,D have lots of cones and C has the most cones.

9. Task 1: Conduct the following experiment with a partner.
Close your left eye. Look straight ahead with your right eye.
Hold your right arm horizontally backwards (see first picture).
Your partner will give you a colored piece of paper.
Bring your arm slowly to the front (like shown in the pictures).
Write down beneath every picture what you can see at the respective angle.
Task 2: Interpret the results of your experiment. Relate it to the distribution
of rods and cones on your retina.
Make a hypothesis about the function of cones and rods.
Hand in your work. Don’t forget your name!

10. Watch Tedtalk on sight :
Practical : Eye experiments (various tasks)

11. Practical observation of near and distant object
WALT know accomodation in the
human eye
Practical observation of near and distant object
using a finger to focus.
Questions :
Did you experience any delays in focusing?
Knowing the structure of the eye, how do you
think this feat is accomplished?
Compare your eye with a camera. Worksheet.
Focal length comparison.

12. Compare the eye and camera.

13. Accomodation in the human eye
The ability of the lens to change its shape
to focus near and distant objects
is called accommodation.
Image credit: Wikipedia
Task : Draw the diagram in your folder. Use a pencil! Size : Half A4 page.
Label distant object and near object. Describe the light rays from both objects.
Describe the lens shape for both .

14. Accommodation How accomodation works Object Ciliary muscles
Suspensory ligaments
Muscle tension on lens
Lens shape
near
contract
slackened
low
fat
distant
relax
stretched
high
thin

15. Source : http://hyperphysics.phy-astr.gsu.edu/hbase/vision/accom.html

16. Presbyopia Age related change in vision.
Difficulty in seeing near objects.
Caused by the change in ablity of the lens to
change shape. Believed to be due to thickening of the lens and
the inability of the ciliary muscle to contract.
The process of accomodation in the eye is not efficient.
Describe three common disorders of the eye. Include myopia and hyperopia.
What is it? Symptoms? Causes? Treatment?

17. - Short vision is good
- Can’t see far objects clearly
- Far vision is good
- Can’t see near objects clearly.
Source : clinicaomegalanzarote.com

18. EYE DISSECTION – practical
Demonstration
Students to dissect eye and complete worksheet.
Eye tasks – station work.

19. Nerve signals travel from each eye along the corresponding optic nerve and other nerve fibers (called the visual pathway) to the back of the brain, where vision is sensed and interpreted. The two optic nerves meet at the optic chiasm, which is an area behind the eyes immediately in front of the pituitary gland and just below the front portion of the brain (cerebrum). The optic nerve from each eye divides in the optic chiasm. Half of the nerve fibers from each side cross to the other side and continue to the back of the brain. Thus, the right side of the brain receives information through both optic nerves for the left field of vision, and the left side of the brain receives information through both optic nerves for the right field of vision. The middle of these fields of vision overlaps. It is seen by both eyes (called binocular vision).
An object is seen from slightly different angles by each eye, so the information the brain receives from each eye is different, although it overlaps. The brain integrates the information to produce a complete picture. This process is the basis of stereo vision or depth perception.
Source :

20. Think-Pair-Share – True or false!
1. Prey animals like the rabbit have a large area of binocular vision
2. The rods of the retina function in dim light and do not respond well to colour.
3. The lacrimal glands secrete fluid that washes the outer surface of the eye and keeps it moist.
4. The conjunctiva is the inner lining of the eyeball.
5. When the eye focuses both the lens and the cornea change in shape.
6. The cones of the retina are more numerous in the region of the eye known as the fovea.
7. Vitamin E is required in the diet to make the visual pigment found in the cells of the retina.
8. The size of the pupil changes in different light intensities.
9. The parasympathetic nervous system brings about dilation (widening) of the pupil.
10. Nocturnal animals are usually colour-blind.

21. 1. Prey animals like the rabbit have a large area of binocular vision
1. Prey animals like the rabbit have a large area of binocular vision. F Prey animals like the rabbit have a large area of monocular vision so they can see predators approaching and only a small area of binocular vision.
2. The rods of the retina function in dim light and do not respond well to colour. T
3. The lacrimal glands secrete fluid that washes the outer surface of the eye and keeps it moist. T
4. The conjunctiva is the inner lining of the eyeball. F The conjunctiva is the fine membrane covering the cornea of the eye.
5. When the eye focuses both the lens and the cornea change in shape. F Only the lens changes shape. The shape of the cornea is constant.
6. The cones of the retina are more numerous in the region of the eye known as the fovea. T
7. Vitamin E is required in the diet to make the visual pigment found in the cells of the retina. F vitamin A is the vitamin required to make the visual purple of the sensory cells of the retina. It is found in carrots and green vegetables.
8. The size of the pupil changes in different light intensities. T
9. The parasympathetic nervous system brings about dilation (widening) of the pupil. F The parasympathetic nervous system controls constriction of the pupil.
10. Nocturnal animals are usually colour-blind. T