The Nervous System
Main parts of the nervous system THE BRAIN is the center of the nervous system Your nervous system is a system of nerve cells that connect your brain with every part of your body THE SPINAL CORD is the main nerve of your body. 31 pairs of nerves branch out from your spinal cord
JOBS of nervous system Sends messages from the brain to the rest of the body along nerve cells (neurons) You taste, hear, and smell with your brain Sensory nerve cells in your body send signals to your brain Your brain sorts these messages and tells you what you are seeing, hearing, tasting, smelling, or feeling
More about the neurons They are also called neurons Your brain has about one trillion neurons Your spinal cord has one billion neurons Neurons collect, receive, and send information very quickly around your body They are found throughout your body-eyes, ears, mouth, nose, skin, muscles, joints…..
Dendrites and Axons Short twig like fibers They receive nerve signals and send them into the bodies of nerve cells These signals leave the cells on longer fibers called axons Axons transmit information from one neuron to another
MORE ABOUT THE BRAIN There are 3 parts of the brain The cerebellum- controls coordination and complex movements of your muscles (like playing sports) Cerebrum- largest part of brain. Controls your ability to think, learn, remember Brain stem- Control important life processes that take place in your body (attention, arousal, and consciousness…) All info passes thru here on way to brain
Interesting facts about brain The right half of the brain controls the movement on the left side of your body The left half controls the right side of your body Weight = 1300-1400 grams or 3 lbs (as adult) Weight = 350-400 grams (as infant) Unconsciousness will occur after 8-10 seconds after loss of blood supply to the brain. The world record for time without sleep is 264 hours (11 days) by Randy Gardner in 1965
Interesting facts about spinal cord Length of human spinal cord is 43-45 cm Weight is 35 grams 31 spinal nerves
SPINAL CORD