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THE NERVOUS SYSTEM

THE NERVOUS SYSTEM. WHAT PARTS DO YOU KNOW THAT ARE IN THE NERVOUS SYSTEM?. Brain. Spinal Cord. Peripheral Nerves. Neurons. The cells that make up nerves are called Neurons. Extending from each cell body are extensions of the cell called dendrites.

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THE NERVOUS SYSTEM

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  1. THE NERVOUS SYSTEM

  2. WHAT PARTS DO YOU KNOW THAT ARE IN THE NERVOUS SYSTEM? • Brain • Spinal Cord • Peripheral Nerves

  3. Neurons • The cells that make up nerves are called Neurons.

  4. Extending from each cell body are extensions of the cell called dendrites. • Dendrites are the information receptors. They get info and carry it to the cell body.

  5. Information is carried away from the cell body by the Axon. • Information is carried as an electrical signal called Action Potentials. • Around the Axon is the Myelin Sheath a lipid layer that protects and keeps the electrical signal insulated.

  6. How are neurons connected? • Synapses!!

  7. Synapses • Individual neurons do not touch each other or other cells. • Communication is carried through a Synapse. At each synapse is a small gap between the axon terminal and the dendrites of the next cell.

  8. Close up look at your synapse AXON What is this in the membrane? The synapse - where the action happens Transport protein The next cell’s plasma membrane

  9. How does the Synapse carry the signal? 2. Vesicles with chemicals called Neurotransmitters move down the axon toward the axon terminal. 3. Chemicals are released and diffuse toward the next cell’s plasma membrane 4. The chemicals open up the transport proteins and allow the signal to pass to the next cell - what type of diffusion is this?

  10. Nerve Impulses • How does the signal in a get started? • How does it stimulate the chemicals (nuerotransmitters) down the axon? • Answre: Ions (charged particles)

  11. Membrane Potential • Every cell of your body has an electrical charge inside and a different electrical charge outside. • The membrane along the axon is the same as any other cell.

  12. Resting Potential • When a cell is at rest there is more and negatively charged proteins inside the cell and more positively charged sodium outside the cell. • Positively charged potassium are able to move back and forth as needed.

  13. Impulses • When a nerve cell is stimulated it opens up the sodium pumps allowing positive sodium ions to flow through the membrane. • This difference in charge causes a domino effect down the axon to the axon terminal.

  14. Impulse • Shortly after the sodium pump opens it closes and positive potassium flow out of the axon. • This is the signal to stop transmitting. After an impulse the cell has to regain the sodium, potassium balance this is called the Refectory Period.

  15. The Brain vs Spinal Cord About how many neurons are in the human brain? 100 billion About how many neurons are in the spinal cord? 1 billion How long do you think the longest axon in the world is? around 15 feet

  16. How many synapses are in one neuron? 1,000 to 10,000!!

  17. What do you think can change neurons and their connections? • Accidents • Drugs • Alcohol • Disease

  18. Drugs and alcohol bind important receptors on neurons

  19. Repeated binding causes the neuron to die

  20. Alcohol damaged dendrites - can repair after abstinence Alcohol blocks receptors and slows down transmission

  21. Why are neurons connected?

  22. REFERENCES • http://faculty.washington.edu/chudler/facts.html • http://occawlonline.pearsoned.com/bookbind/pubbooks/campbell6e_awl/chapter0/deluxe.html • JOSHSANESPPT.PPT • www.alfamilyties.org/presentations/The%20Neurobiology%20of%20Adolescent%20Substance%20Abuse%20II.ppt • http://www.nsbri.org/Education/High_Act.html • http://www.pfizer.com/brain/teachers_html.html • http://www.research.buffalo.edu/quarterly/vol10/num01/n1.shtml • http://www.aim-digest.com/gateway/pages/brain/articles/myths.htm • http://www.nida.nih.gov/pubs/teaching/Teaching5/Teaching3.html • http://www.accessexcellence.com/AE/ • http://psych.colorado.edu/~kenth/Image14.gif

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