1. The Nervous System Neural Anatomy

2. Neurons: The Building Blocks of the Nervous System Module 7: Neural and Hormonal Systems

4. Nervous System The electrochemical communication system of the body Brings information to the brain from the senses Sends messages from the brain to the body to enact behavior

5. Neuron The basic building block of the nervous system -- a nerve cell Neurons perform three basic tasks –Receive information –Carry the information –Pass the information on to the next neuron

6. Types of Neurons Afferents, or “sensory neurons”, carry information from the body to the brain

7. Types of Neurons Interneurons, found in the spinal cord and the brain, interpret the incoming information and determine the next course of action

8. Types of Neurons Efferents, or “motor neurons”, carry information from the spinal cord or the brain to the rest of the body in order to initiate behavior

9. Parts of the Neuron

11. Parts of the Neuron - Dendrites

12. Parts of the Neuron - Soma

13. Parts of the Neuron - Axon

14. Parts of the Neuron – Myelin Sheath

15. Parts of the Neuron - Terminals

16. Neuron

18. The Neural Network How does the whole system fit together?

19. A neuron is considered at “resting potential” when there is no sensory input and it is awaiting stimulus.

20. A Neural Chain

21. Special receptors in each of the five senses detect stimuli from the outside world.

22. When a neuron receives enough information to pass on, it has reached its “action potential” and fires off the message to the next neuron in the link

23. Once a neuron fires, it must re-set momentarily in order to receive another message. This re-set period is called “refraction”. It cannot fire during this period.

24. A Neural Chain

25. Sensory neurons carry all of the input to the spinal cord.

26. A Neural Chain

27. Interneurons in the spinal cord and the brain process the information and decide the best course of behavior.

28. A Neural Chain

29. Motor neurons from the brain travel back down the spinal cord and out to the appropriate parts of the body with the appropriate behavior instructions.

30. A Neural Chain

31. Neural Communication: The Neural Impulse

32. A neuron firing is like a toilet flushing 1.Like a Neuron, a toilet has a resting potential. The toilet is “charged” when there is water in the tank and it is capable of being flushed.

33. Neuron firing like a Toilet 2. Like a Neuron, a toilet has an action potential. When you flush, an “impulse” is sent down the sewer pipe.

34. Neuron firing like a Toilet 1.Like a neuron, a toilet has a refractory period. There is a short delay after flushing when the toilet cannot be flushed again because the tank is being refilled 2.Like a Neuron, a toilet operates on the all-or-nothing principle – it always flushes with the same intensity, no matter how much force you apply to the handle

38. Communication Between Neurons Module 7: Neural and Hormonal Systems

39. Synapse The electrical message from the dendrite travels down the axon to the terminal buttons. Here, it changes into a chemical message to be transferred to the next neuron. The tiny, fluid filled gap between the axon terminal of one neuron and the dendrite of another neuron is called the synapse.

42. Neurotransmitters A chemical messenger that travels across the synapse from one neuron to the next

43. Neurotransmitters

47. Acetylcholine (ACh) Enables muscle action, learning, and memory Undersupply, as ACh- producing neurons deteriorate, marks Alzheimer’s disease

48. Dopamine Influences movement, learning, attention, and emotion Excessive dopamine receptor activity is linked to schizophrenia; a lack of dopamine produces the tremors and lack of mobility of Parkinson’s disease

49. Serotonin Affects mood, hunger, sleep, and arousal Undersupply is linked to depression; Prozac and other anti-depressants raise serotonin levels

50. Norepinephrine Helps to control alertness and arousal Undersupply can depress mood

51. Endorphins Natural opiates that are released in response to pain and vigorous exercise Endorphins

52. The Structure of the Nervous System

53. The Nervous System

54. Central Nervous System (CNS) The brain and spinal cord The brain is the location of most information processing. The spinal cord is the main pathway to and from the brain.

55. Spinal Cord

56. Divisions of the Nervous System

57. Peripheral Nervous System (PNS) The sensory and motor nerves that connect the central nervous system to the rest of the body Peripheral means “outer region” The system is subdivided into the somatic and autonomic nervous systems.

58. Divisions of the Nervous System

59. Somatic Nervous System The division of the peripheral nervous system that controls the body’s skeletal muscles Contains the motor nerves needed for the voluntary muscles

60. Divisions of the Nervous System

61. Autonomic Nervous System The division of the peripheral nervous system that controls the glands and muscles of the internal organs Monitors the autonomic functions Controls breathing, blood pressure, and digestive processes Divided into the sympathetic and parasympathetic nervous systems

62. Divisions of the Nervous System

63. Sympathetic Nervous System The part of the autonomic nervous system that arouses the body to deal with perceived threats and stress

64. Divisions of the Nervous System

65. Parasympathetic Nervous System The part of the autonomic nervous system that calms the body Brings the body back down to a relaxed state

66. Divisions of the Nervous System

67. The Sympathetic and Parasympathetic Divisions of the Autonomic Nervous System

74. The Sympathetic and Parasympathetic Nervous Systems Physical Responses