1. The Nervous System AN EXCELLENT POWERPOINT ON THE NERVOUS SYSTEM AND HOW IT WORKS.

2. Why study the nervous system?  Nervous system is involved in all things humans do (dream, sleep, eat, wake, feel, think, text)  Two parts: CNS – Central Nervous System (brain and spinal cord) PNS – Peripheral Nervous System (nerve cells that send messages from CNS to all parts of the body)

3. Can you believe the nerve of that pushy salesperson?

4. Well, nerve sells.

5. How does the nervous system work?  Neurons – nerve cells that run through the body  Send and receive messages from muscles and glands  Over 100 billion neurons found in our body That’s more than the amount of dollars in Mr. Bayne’s wallet

6. Mr. Bayne—what are these parts in a neuron?

7. What are these ‘parts’ that you speak of?  Dendrites – Receive the information and pass it thru cell body  Cell body – produces the energy to fuel the activity of the cell  Axon – carries message away from cell body to the terminals (axon endings)  Axon is protected by myelin sheath (white, fatty substance; helps protect and speed up messages)  Axon terminals The end of the neuron, sends out messages

8. Then what?  Once a message reaches the axon terminals, it must jump across a gap  Synapse – the gap that it must jump  It jumps from the axon terminal to the dendrite of the next neuron  If it does not make this jump, the message is lost

9. What types of neurons are there?  Sensory – Nerve cells that carry info to CNS (brain/spinal cord)  Motor – Nerve cells that send messages from CNS to PNS (tells muscles/glands what to do)  Something like a concussion can affect this process

10. We’ve heard so much of these neurotransmitters…what are they?  Chemicals located in axon terminals that send messages across the synapse  Think of them as a spray bottle in how they work  Low levels of chemicals could result in major effects  Low levels of dopamine (which controls motor behaviors) could lead to uncoordinated movements—think of Parkinson’s disease

11. Fascinating so far, right?  Well, there is more!

12. Remind me of what the CNS is.  Central Nervous System – the brain and the spinal cord  Spinal cord – protected by bones of spine  Transmits messages between the brain and the muscles/glands throughout the body  Spinal reflexes – automatic response to something (hand touches stove)  Message goes through sensory neurons to spinal cord; spinal cord instantly sends message back through motor neurons to remove hand)

13. PNS – This is my favorite  Peripheral Nervous System – Takes messages from CNS to the rest of the body  Two main divisions – Somatic and the Autonomic Nervous System  If you were to lay out all the nerve cells in this system, it would be very long.

15. Somatic Nervous System  First part of PNS  Sends sensory messages to CNS (this stove is hot)  Activated by touch, changes in temperature, body position, etc…)  Our motor movements and senses

16. Autonomic Nervous System (here is where things get tricky)  Think ‘automatic’  Regulates body functions necessary for survival (heart beat, breathing, digestion, etc..)  Two divisions – Sympathetic and Parasympathetic  ‘S’ for Sympathetic, ‘S’ for stress  ‘P’ for Parasympathetic, ‘P’ for Peace

17. Sympathetic  Activated when person is going into action (under stress)  Prepares the body to confront a situation or to run away  “Fight or flight” response  Example: You see someone in your yard with a gun, how do you respond?  Or you look behind you and see an angry dog?

18. Parasympathetic – At peace  Restores the body’s reserves of energy when at rest;  Heart rate/blood pressure are normalized, breathing is slowed

19. Mr. Bayne, can you show us a chart?

20. Nervous System PNS Somatic Autonomic Sympathetic Parasympathetic CNS Spinal Cord Brain

21. Scenario  Mr. Bayne sees that you got a wrong answer on a test, and as a punishment, he steps on your toe. Create a detailed description of how this involves the nervous system, using the following terms:  Somatic, autonomic, sympathetic, parasympathetic, dendrite, sensory, motor, axon, myelin sheath, fight or flight