Baby Senses

http://www.dailymotion.com/video/xenyhq

Even a visit to the grocery store can overload the senses. It is noisy, bright and smelly. The nose is working overtime. High up inside specialized nerves dangle in the air stream. They detect chemicals in the air and send an electrical signal to the brain which interprets the signals as smells. The nerves are super sensitive. Every smell is a new sensation. The same goes for our hearing. Strange new world, strange new sounds. Sound waves vibrate the ear drum. On the other side of the ear drum, these tiny bones the ossicles vibrate in response. They’re the smallest bones in the body but without them we would never hear a thing. They use leverage to amplify the vibrations hitting the ear drum 22 times. The amplified vibrations now enter the inner ear or cochlea. It’s lined with delicate hairs. When vibrations pass through, the hairs vibrate. At the base are the fragile hairs for high frequency sounds, at the top low frequency hairs each one 200times thinner than a hair on our head. Over time load noises will damage these hairs but at this age they are perfect. Our hearing will never be this good again. The story is different for eye sight. We are born with very underdeveloped vision. Even at one month the world is blurred and mostly black and white. Every aspect of our vision is rudimentary. The eye muscles are immature keeping us from pointing our eyes where we want to. Inside the eye the lens muscles stil can’t focus and the lens flips the image it receives. All through life we see the world upside down. The Picture only gets reoriented in our brains. Right now the Picture is on the retina, the screen at the back of the eye. The retina has two types of cells, rods and cones, which transform the light that hits them into electric signals. The cones detect colour information but because they’re not developed yet, we see mostly in black and white during our first month. From the retina the signals travel along 2 thick nerves under the brain. At the back is where we process visual information. When the image arrives, the real challange begins, our image immature brains haven’t learnt to interpret the data yet. That’s changing fast.