B1 The nervous system

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Cornea function...
Refracts (bends) light rays
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Lens function...
Refracts (bends) light rays and focuses it onto the retina
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Retina function...
Contains light receptors (image is focused here), contains 2 photoreceptor cells: rods (dim light and black&white) and cones (colour)
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Iris function...
Controls how much light enters your pupil and decided colour of eye
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Optic nerve function...
Carries nerve impulses to the brain (back of eye)
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Ciliary muscle function...
Controls suspensory ligament
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Suspensory ligament function...
Alter the shape of the lens in focusing
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Binocular vision...
Helps judge distance by comparing images from each eye
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Accomodation is when...
The eye focuses light from distant or near objects by altering the shape of lens
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To focus on distant objects...
Ciliary muscles relax + suspensory ligaments tighten = less rounded shape
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To focus on near objects...
Ciliary muscles contract+ suspensory ligaments slacken = more rounded shape
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Red-green colour blindness is caused by...
lack of specialised cells in the retina
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Long sight...
Eyeball too short or lens too thin so image is focused BEHIND retina
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Short sight...
Eyeball too long or lens too rounded so lens refracts light too much -> image is focused IN FRONT of retina
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Long and short sight is correct by...
1) Corneal surgery 2) Lens in glasses 3) Contact lens
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Convex lens corrects...
Long sight
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Concave lens corrects...
Short sight
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Reflex action links...
Stimulus->receptor->sensory neurone->central neurone system->motor neurone->effector->response
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Spinal reflex pathway...
Reflector->sensory neurone->relay neurone->motor neurone->effector
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How are neurones adapted?
1) Long 2) Dendrites (branched endings) that pick up impulses 3) Insulator sheath
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A synapse is...
A gap between neurones
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What happens when an impulse arrives?
The release of a transmitter substance is triggered -> diffuses across the synapse -> it binds with receptor molecules in the membrane of the next neurone -> impulse continues
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Other cards in this set

Card 2

Front

Refracts (bends) light rays and focuses it onto the retina

Back

Lens function...

Card 3

Front

Contains light receptors (image is focused here), contains 2 photoreceptor cells: rods (dim light and black&white) and cones (colour)

Back

Preview of the back of card 3

Card 4

Front

Controls how much light enters your pupil and decided colour of eye

Back

Preview of the back of card 4

Card 5

Front

Carries nerve impulses to the brain (back of eye)

Back

Preview of the back of card 5
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