The Eye Flashcards
(15 cards)
What is the role of the Cornea?
The Cornea refracts (bends) light into the eye
What is the role of the Iris?
The Iris controls the diameter of the pupil, therefore how much light enters the eye.
What is the role of the Lens?
The Lens focuses light onto the Retina
What is the role of the Retina?
The Retina is the light sensitive part of the eye, with light receptors
What are the names of the two types of light receptors found in the Retina? (2)
- Rods
- Cones
What is the role of the Optic Nerve?
The Optic Nerve carries impulses from receptors to the brain
Facts about Rods: (2)
1) More sensitive in dim light
2) Can’t see colour
Facts about Cones & Where they are found (2)
1) Sensitive to colours
2) Found all over the retina but mostly in the Fovea
Bright light triggers a _____ that makes the pupils _____ allowing ___ light in. ______ _______ detect bright light and send a message along the _____ _____ to the ______. The message travels along the _____ neurone to a ______ neurone which tells circular muscles in the _____ to contract, making the pupil smaller.
brain, less, more, reflex, smaller, bigger, light receptors, sensory neurone motor, relay, iris, contract, expand,
Bright light triggers a REFLEX that makes the pupils SMALLER allowing LESS light in. LIGHT RECEPTORS detect bright light and send a message along the SENSORY NEURONE to the BRAIN. The message travels along the RELAY neurone to a MOTOR neurone which tells circular muscles in the IRIS to contract, making the pupil smaller.
In dim light, the _____ ______ are told by the _____ to ______ which makes the pupil _____
bigger, smaller, radical muscles, brain, expand, contract
In dim light, the RADICAL MUSCLES are told by the BRAIN to CONTRACT which makes the pupil BIGGER
How does the eye focus light?
By changing the lens.
To look at near by objects, the _____ muscles _____, which slackens the ______ _______. The lens becomes more ______.
suspensory ligaments, ciliary, curved, straight, contract, expand
To look at near by objects, the CILIARY muscles CONTRACT, which slackens the SUSPENSORY LIGAMENTS. The lens becomes more CURVED.
When looking at distant objects the _____ muscles ______ which allows the _______ ______ to pull tight. This makes the lens go _____ ( less ______)
RELAX, CONTRACT, SUSPENSORY LIGAMENTS, THIN, CURVED, CILIARY
When looking at distant objects the CILIARY muscles RELAX which allows the SUSPENSORY LIGAMENTS to pull tight. This makes the lens go THIN ( less CURVED)
Long sighted people are unable to focus on _____ objects. This occurs when the _____ or lens doesn’t _____ the _____ enough or the eyeball is too ____. The images of nearby objects are bought into focus _____ the _____.
in front, behind, near, short, long, bend, cornea, light, dark, retina
Long sighted people are unable to focus on NEAR objects. This occurs when the CORNEA or lens doesn’t BEND the LIGHT enough or the eyeball is too SHORT. The images of nearby objects are bought into focus BEHIND the RETINA.
Short sighted people are unable to focus on ____ objects. This occurs when the cornea or ____ bends the _____ too _____ or the eyeball is too _____. The images of distant objects are bought into focus __ ____ of the _____.
in front, behind, retina, far, lens, much, little, long, short, light
Short sighted people are unable to focus on FAR objects. This occurs when the cornea or LENS bends the LIGHT too MUCH or the eyeball is too LONG. The images of distant objects are bought into focus IN FRONT of the RETINA.
