1. The Nervous System Neurons, Nerves, the Brain and Neurotransmitters

2. Organization of the nervous system

3. The central nervous system = The Brain + Spinal Cord Spinal cord: A collection of neurons and supportive tissue running from the base of the brain down the center of the back –Protected by spinal column But the central nervous system is only one part…

4. Spinal Reflexes: Who Needs a Brain? For example, pulling your hand away from something hot No need to involve the brain “Spinal reflexes” go right from the skin to the spinal cord back to the muscle Neurons that serve the skin and muscles in arms and legs are part of the peripheral nervous system So, spinal reflexes involve the central and peripheral nervous systems

5. Organization of the nervous system

6. Peripheral Nervous System 43 pairs of nerves –Nerves are bundles of many, many neurons 12 pairs go straight to the brain 31 pairs go to the spinal cord (remember the spinal reflexes?)

7. Peripheral Nervous System Autonomic (think “automatic”): controls heart, stomach, etc. Somatic: Arms and legs – things you control voluntarily

8. Autonomic Nervous System Sympathetic: Prepares the body for ACTION! Parasympathetic: Rests the body and restores to get ready for next round.

9. Organization of the nervous system

10. A Neuron is a very special cell: You have about 100 billion of them! Dendrites: Receive information from other neurons and transmit toward the cell body

11. A Neuron is a very special cell: You have about 100 billion of them! Cell body: Keeps the neuron alive and determines whether it will fire Axon:Extending fiber that conducts impulses away from the cell body and transmits to other cells.

12. Neurotransmitter Chemical released by a transmitting neuron at the synapse and capable of affecting the activity of a receiving neuron

13. Serotonin – involved in treatment of depression Dopamine Acetylcholine (Ach) Norepinephrine Gamma aminobutyric acid (GABA) Glutamate Endorphins – “runner’s high” Major neurotransmitters

14. The brain stem Pons: Involved in sleeping, waking, and dreaming

15. The brain stem Medulla: Responsible for certain automatic functions such as breathing and heart rate chapter 4

16. The brain stem Reticular activating system: Arouses cortex and screens incoming information chapter 4

17. The cerebral cortex: curly