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Overview
Soaring on the updrafts a sharp-eyed eagle stays aloft with barely a tug of its wing feathers. The offshore breeze changes direction slightly and the eagle’s muscles make endless slight adjustments so that flight seems effortless as it hovers over the cliffs. Below, on the coastal bluff overlooking the ocean, a near-sighted rabbit, nose twitching in the wind and unaware of the keen eyes scanning far over head, grazes on spring flowers. The rabbit is intent on tasting the juicy sweetness of the stems, hopping from one to the next. Detecting motion, the eagle collapses its wings in a terrifying nose dive to the ground. The eagle is a master at judging distance so just before crash landing the wings unfold like graceful parachutes as sharp talons grab for the rabbit. Life responds. If the rabbit is very alert or the eagle slow, rabbit might not become lunch for baby eaglets. Generally, humans are not as close to being a meal for a predator but our response to events happening around us is very similar to that of the rabbit and the eagle.
What is it that responds and what happens when the response mechanism fails? The nervous system is the window on the world for animals. We perceive the world around us, move around in it, analyze it, fear it, talk to it, and enjoy it all because of a complex detection and response network. The nervous system is composed of sensory receptors, neurons, the spinal cord and the brain. After an outside stimulus is detected the message travels through a series of neurons to the spinal cord and then on to the brain. Inside the brain are many different areas that respond to the various types of stimuli, sending back a command to move muscles. If something goes wrong within the brain then the detection and response system may short circuit or fail altogether. That rabbit’s brain is on overdrive as soon as it perceives the danger falling out of the sky. Its survival and the lives of its offspring depend on the speed of detection and response going on at the molecular level throughout its body. Anything that affects the system can mean death to the rabbit or hunger for the eagle.
Why This Science Matters
Everyday most of us receive important information from other people, call the dog or chat on the phone to a friend. We laugh, sing, and yell and create all the sounds that we call speech. Our brains take in information through the various sense organs and interpret it. We feel happy or sad because of movies or experiences. We run on a track and feel the pressure as our feet pound the dirt. What would it be like if we could not do those things? How would we compensate? Doctors and researchers are very interested in what can go wrong with the system that makes all of that happen. External injuries damage the nervous system and internal diseases such as stroke create serious changes to the quality of life for many people each year. Some inherited genetic traits influence the functioning of the nervous system also. Throughout life, the brain is changing, going through natural developmental stages that are influenced by both nature and nurture, genetics and environmental conditions.
Scientists study what can go wrong because it gives clues to the structures and functions of the nervous system. They are especially interested in how the brain develops and how signals get to the brain, where in the brain they are processed and how the brain regulates the response. When there is damage to certain parts of the brain, such as a stroke may cause, the physical effects can help to define where certain functions are processed in the brain. Studying damage to the brain at different developmental stages in life can help medical researchers to find effective treatments. The first important event to understand is how the body sends the message.
Lesson developed by Ann Marie Wellhouse, founder of River Valley Charter School, who currently teaches classes in science leadership and science investigations and has also taught biology and earth science.
