The Central Nervous System

The Nervous System  The Central Nervous System consists of the brain and the spinal cord  Nerves branching off the brain and spinal cord make up the Peripheral Nervous System  These two work together to tell the brain what is happening inside and outside the body  Makes sure the body responds appropriately to the messages sent  The taking in and reporting of information is called homeostasis

The Nervous System  Made of special cells called neurons  Each neuron contains dendrites and axons  Dendrites– carry nerve impulse to the neuron  Axons – carry impulses (information) away from the neuron

How it works…  An impulse reaches the top of an axon and jumps to another via an electrical impulse at the synapse (structure that permits a neuron to pass a signal to another cell).  The axon then releases a chemical that allows the impulse to cross the synapse to the next neuron.  This is how messages travel through the nervous system

Time to Brainstorm!! Can you think of an example in which a message is instantly received by the brain and the body appropriately reacts to the stimulus? Discuss with your group.

The Brain  The main information center of the body  Messages travel to the brain through the synapses of the neurons in the central nervous system  The brain interprets this information and allows the body to act upon it

Three parts of the brain  The Cerebrum  The Cerebellum  The Brain Stem (Medulla)

The Cerebrum  Largest area of the brain  Makes up 85% of brain’s weight  Found at the front of the brain  Divided into a right (music, colors, and shapes) and left (math, logic, and speech) half (hemisphere)  Functions include learning, interpreting information, logical reasoning, abstract thought, speech and language, vision, interpreting the senses, and memory (short term and long term)

The Cerebellum  Second largest area of the brain  Controls voluntary muscle movement  Controls balance, movement, and coordination

The Brain Stem (Medulla)  Found between the spinal cord and cerebellum  Connects the rest of the brain to the spinal cord  Sorts through the millions of messages that the brain and the rest of the body send back and forth  Controls all your body’s involuntary actions  Controls breathing, heartbeat, digesting food, circulating blood, and salivating for example

Be Good To Your Brain  Eat healthy foods. They contain potassium and calcium, two minerals that are important for the nervous system.  Get a lot of playtime (exercise).  Wear a helmet when you ride your bike or play other sports that require head protection.  Don't drink alcohol, take drugs, or use tobacco.  Use your brain by doing challenging activities, such as puzzles, reading, playing music, making art, or anything else that gives your brain a workout!