The Brain and Eyes
Your brain is the control centre for your entire body, made up of billions of connected neurons. It's divided into several key regions that each have specific jobs.
The cerebrum is split into two hemispheres with a highly folded surface. It handles your intelligence, personality, language skills and memory. Below it sits the cerebellum, which controls your balance, coordination and muscle activities. The medulla oblongata manages unconscious but vital functions like breathing and heart rate, while the hypothalamus regulates your body temperature and water balance.
Your eyes work like sophisticated cameras. Light enters through the cornea (which refracts light and allows diffusion) and passes through the pupil (controlled by the iris). The iris reflex adjusts pupil size - constricting in bright light and dilating in dim conditions. The lens focuses light onto the retina where special cells (rods for black and white vision, cones for colour) generate signals that travel along the optic nerve to your brain.
Did you know? Neuroscientists map brain functions using MRI scanning, which uses magnetic fields and radio waves to show the active parts of your brain without surgery.
Vision problems occur when the eye shape isn't quite right. In short-sight, the eyeball is too long, causing images to focus in front of the retina. This is corrected with concave lenses. With long-sight, the eyeball is too short, focusing images behind the retina, requiring convex lenses as correction.
Accommodation is how your eye adjusts focus between near and distant objects. When looking at something close, ciliary muscles contract, loosening suspensory ligaments, allowing the lens to become thicker. For distant objects, these muscles relax, pulling the ligaments tight, making the lens thinner.