– The part of your eye that gives it its color is called the iris. It has lots of tiny muscles that open your pupil ( the round hole in the center) to let in more light when it’s dark, or make it smaller when it is very bright out.
– What film is to a camera, the retina is to your eye. It has millions of two main nerve cells to catch light. Rods – which are mostly around the sides, are best at helping you to discriminate light and dark. Cones, which are near the center, are for detecting color. Nerve cells from the retina connect your eye to the parts of the brain that process vision – the occipital lobes which are located in the back of your head.
– Like your fingerprints, irises and retinas are individual.
– The three smallest bones in the body – named the hammer,the anvil and the stirrup (the smallest, at about 3 millimeters) pass sound from your eardrum to your inner ear.
– The inner ear has special nerve cells to pass sound information for processing by the brain, but part of the inner ear helps you to keep your balance.
– There are about 10 million smell receptors up in the space behind your nose for detecting smells. Working together with you brain, this group of nerve cells is able to detect about 10,000 different odors.
Taste – You are born with about 10,000 taste buds, but this drops over time to about 5000 by the time you are old. Taste buds detect sweet, sour, salty and bitter. Tasting is about 80% smell, and your sense of smell increases when you are hungry.
– The skin is the largest organ in the body, weighing in at about 6 – 10 lb. Your skin detects touch via receptors for pain, pressure and movement, cold and heat.
– Most touch receptors are for pain. Skin is least sensitive in the middle of your back, and most sensitive in hands, fingertips, and lips
Hopefully this is enough to whet your appetite for fun and fascinating facts about the amazing human body. Keep learning.