GCSE Biology · Edexcel 1BI0 · Topic 2D
The brain and the eye
Key points
- Brain regions: the cerebrum controls thinking, memory, language and conscious actions; the cerebellum coordinates balance and movement; the medulla oblongata controls automatic actions such as heart rate and breathing.
- Brain injury and disease are hard to treat because the brain is delicate and complex; CT and PET scans help doctors look inside it without surgery.
- Spinal cord injuries can be difficult to repair and may cause loss of feeling or movement.
- Eye structures: cornea and lens focus light; the iris controls pupil size; the retina contains rods (dim light) and cones (colour); the optic nerve carries impulses to the brain.
- Short-sightedness (corrected with a concave lens) and long-sightedness (a convex lens). Cataracts make the lens cloudy and can be treated by replacing it. Colour blindness is caused by faulty cones.
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The brain and the eye are two of the most complex organs in the body. This sub-topic covers what the main parts of the brain do, why nervous system damage is so hard to treat, and how the eye forms an image and how its defects are…
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