Human Body feed
Light → signals
The retina is light-sensitive tissue at the back of the eye, where photoreceptor cells convert light into electrical signals. Those signals pass through retinal circuits and the optic nerve before the brain builds visual perception.
300
Babies have more separate skeletal pieces than adults, often described as about 300 bones compared with the usual adult count of 206. The newborn number is approximate because developing bone and cartilage are not always counted the same way.
1 cm
People are usually slightly taller after a night lying down because spinal discs regain fluid when unloaded. Around a centimeter is a useful rough illustration, not a fixed daily change for everyone.