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The Nervous System and the Eye - Coggle Diagram
The Nervous System and the Eye
Looking at a distant object
Light rays reflecting off object are almost parallel to each other
Thinner lens as only a little refraction is needed
Ciliary muscles relax, pulling on the suspensory ligaments
The suspensory ligaments become taut, pulling on the edge of the lens
The lens becomes thinner and less convex
Light rays from distant object are sharply focused on the retina
Photoreceptors are stimulated
Nerve impulses are produced and transmitted by the optic nerve
Brain interprets nerve impulses, person can see the distant object
Looking at a near object
Light ray reflecting off of object are diverging
Lens has to be thicker
Ciliary muscles contract, relaxing their pull on the suspensory ligaments
Suspensory ligaments slacken
Lens becomes thicker and more convex
Light rays from near object are focused sharply on the retina
Photoreceptors are stimulated
Nerve impulses are generated and are transmitted vie the optic nerve
Brain interprets nerve impulses, person can see near object
Increase in Light Intensity
When photoreceptors in retina detect this change, and generate nerve impulses as they get stimulated
The nerve impulses are transmitted via the sensory neurone to the relay neurone in the brain across a synapse
The relay neurone then transmits nerve impulses to the effector muscle in the iris via the motor neurone across a synapse
This results in the circular muscles contracting and the radial muscles relaxing, allowing less light to enter the pupil
Decrease in Light Intensity
Photoreceptors in retina detect this change and generate nerve impulses as they get stimulated
The nerve impulses are transmitted from the sensory neurone to the relay neurone in the brain across a synapse
The relay neurone then transmits nerve impulses to the effector muscle in the iris via the motor neurone, across a synapse
This results in the circular muscles relaxing and the radial muscles contracting, allowing more light to enter the pupil