The eye Flashcards
What’s the Scalera?
The tough supporting wall of the eye
What’s the cornea?
The transparent outer layer found at the front of the eye
What’s the iris?
It contains muscles that control the diameter of the eye
.Therefore it controls the amount of light that enters the eye
What’s the lens?
It focuses light onto the retina
What’s the retina?
Contains receptor cells sensitive to light and colour
What are cone cells?
Light sensitive cells that detect colour
.They are found in the retina
What are rod cells?
Extremely light sensitive cells, that helps us see in the dark
.Can only detect black and white
.Why we can only see black and white in the dark
What do the ciliary muscles and suspensory ligaments do?
Control the shape of the eye
What’s the optic nerve?
carries impulses from receptors to the brain
How does the iris react to bright light?
1)The circular muscles contract and the radical muscles relax
2)This causes the pupil to get smaller(constricts)
3)This reflex protects your light sensitive cells at the back of your eye, from getting damaged
How does the iris react to dim light?
1)The circular muscles relax and the radical muscles contract
2)This makes the pupil wider(the pupil dilates) which allows for more light to enter the eye
3)This allows for more light to reach the light sensitive rod cells at the back of the eye
What is the process called- when the eye focuses light on the retina by changing the shape of the lens?
Accomodation
What’s the process in the eye, when looking at objects near by?
1)The ciliary muscles contract and the suspensory ligaments slacken(relax)
2)The lens becomes more curved
3)This increases the amount of light refracted
What’s the process in the eye, when looking at distant objects?
1)The ciliary muscles relax and the suspensory ligaments contract
2)The lens becomes thinner(less curved)
3)This means your eye refracts a smaller amount of light
What are some causes of long sightedness?
The eyeball is to short
The eye doesn’t refract light enough
The lens could be the wrong shape
What are some treatments for long sightedness?
Glasses with convex lenses (curved outwards)
.Laser eye surgery
.Replacement lens surgery
What are some causes of short sightedness?
The eyeball is to long
The lens is the wrong shape
The eye refracts to much light
What are some treatments for short sightedness?
Glasses with concave lenses (curve inwards)
Laser eye surgery
What’s the medical name for long sightedness?
hyperopia
What’s the medical name for short sightedness?
myopia
What happens that results in long sightedness?
The images of nearby objects are brought into focus behind the retina
What happens that results in short sightedness?
The images of distant objects are brought into focus in front of the retina
