1. The Nervous System

2. the electrochemical ( chemical reactions brought about by electricity) communication system of the body

3. Neuron cells of the nervous system (brain, spinal cord, nerves) Neurons perform three basic tasks: receive information carry information pass information to the next neuron

4. Neuron Development birth3 months2 years

5. Parts of the Neuron Dendrites DETECT

6. Parts of the Neuron

9. Dendrites DETECT Axons ANNOUNCE

10. Neurons

11. Neural Communication: The Neural Impulse

12. Action Potential brief electrical charge that travels down the axon

13. All-or-None Principle if a neuron fires it will always fire at the same intensity doesn’t matter if there is a strong or weak stimulation

14. Refractory Period “recharging phase” when a neuron, after firing, cannot generate another action potential once complete the neuron can fire again

15. Resting Potential neuron is at rest & capable of generating an action potential neuron is set and ready to fire

16. How are the 3 phases of neuron communication like a toilet? Action potential – when you flush an “impulse” is sent down the sewer pipe Refractory period – delay after flushing when the toilet can not be flushed again Resting Potential – toilet “charged” when there is water in the tank and is capable of being flushed again All-or-none-principle – always flushes with the same intensity no matter how much force you apply to the handle

17. Review Questions (think! don’t say the answer out loud…yet) 1. What are the three phases of communication within a neuron? 2. What is the all-or-none principle?

18. Communication Between Neurons

19. “How do messages travel from one neuron to the next?”

20. Synapse neurons do not come into contact with each other Synapse - tiny, fluid filled gap between the axon terminal of one neuron and the dendrite of another neuron

21. Neurotransmitters chemical messengers travel across the synapse fit into receptor sites on the dendrite of the next neuron

22. Neurotransmitters can stay only in receptor sites designed to fit their shape serve two functions: 1. Excitatory Effect 2. Inhibitory Effect

23. Excitatory Effect makes it MORE likely that the receiving neuron will generate an action potential

24. Inhibitory Effect makes it LESS likely that the receiving neuron will generate an action potential

25. Neurotransmitters

26. Review Questions (think! don’t say the answer out loud…yet) 1. How do messages travel from one neuron to the next? 2. How do neurotransmitters that have an excitatory effect impact neurotransmission? What about an inhibitory effect?

27. Neurotransmission Simulation http://www.brainexplorer.org/neurolo gical_control/Neurological_Neurotran smission.shtml#

28. The Central & Peripheral Nervous Systems

29. The Nervous System

30. Central Nervous System (CNS) brain & spinal cord brain: where most information processing takes place spinal cord: main pathway information follows as it enters & leaves the brain

31. Spinal Cord

32. Divisions of the Nervous System

33. Peripheral Nervous System (PNS) all the nerves that feed into & branch out from the brain & spinal cord

34. Divisions of the Nervous System

35. Somatic Nervous System contains: motor nerves controls: voluntary movements of skeletal muscles

36. Divisions of the Nervous System

37. Autonomic Nervous System Controls: glands & muscles of the internal organs monitors the automatic functions (breathing, blood pressure, and digestive processes)

38. Divisions of the Nervous System

39. Sympathetic Nervous System controls: arousal fight-or-flight response prepares the body to deal with threats or challenges

40. Divisions of the Nervous System

41. Parasympathetic Nervous System controls: calming brings the body back to a relaxed state

42. Divisions of the Nervous System