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The Nervous System

By Po-Han Chen. The Nervous System. What good does it make?.

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The Nervous System

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  1. By Po-Han Chen The Nervous System

  2. What good does it make? Creatures on the world can feel the surrounding in order to adapt the environment for survival. Animals relies on Endocrine system and Nervous system to adjust itself. Nervous system controls muscle contraction and coordinate the organs within a short time in order to protect itself. 3% of overall mass, but it is the most complicated system in body

  3. Nervous System • The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals between different parts of its body

  4. Parts Your Nervous system is mainly made up of The Nerves Spinal cord The Brain

  5. Nerve Cells The nervous system is made up of Neurones. Each neurone consists of a cell body and extending nerve fibre

  6. Neurons can be divided into 3 types Sensory Motor Interneurons Neurons and Synapses

  7. Sensory Neurons INPUT Fromsensory organs to the brain and spinal cord. I.e., from Nose, eyes to brain

  8. Motor Neurons OUTPUTFrom the brain and spinal cord To the muscles and glands.

  9. Interneurons (Relay Neurons) Interneurons carry information between other neurons only found in the brain and spinal cord.

  10. The Neuron can be separated into 4 parts : The cell body Dendrites Axon Myelin sheath Structure of Neuron

  11. The cell body Round structure Contains DNA Dose Protein manufacturing Directs metabolism No role in neural signaling Contains the Cell’s Nucleus

  12. Dendrites Information collectors Receive inputs from neighboring neurons If enough inputs the cell’s AXON may generate an output

  13. Axon Output structure One axon per cell, 2 distinct parts The tube branches at the end and attaches to other cells.

  14. YouTube Video • http://www.youtube.com/watch?v=i-NgGKSNiNw

  15. How neurons communicate • Neurons communicate by electrical signal called the Action Potential. • it is based on movements of ions between cells. • When an Action Potential occurs a molecular message is sent to neighboring neurons

  16. The Big Boss Brain is the organ that controls everything in your body, including your thought and reaction.

  17. Nervous System The nervous system is divided into two sections: Central Nervous System + Outer Nervous System

  18. Central Nervous System The Central Nervous System is made up of Brain and Spinal cord Electrical Signals are carried from the Brain to the receptors through Spinal cord

  19. The Path • Betweenthe receptors and the effectors, the Central Nervous system coordinates the action potentials passing through the nervous system.

  20. Outer Nervous System The Outer Nervous System is made of the nerves and the sense organs Sense Organs includes Skin - Touch Nose - Smell Tongue - Taste

  21. Nerve Impulse Electrical signals are carried through nerve impulse which is widely spread in the body

  22. Action Potential An action potential is a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls, following a stereotyped trajectory

  23. Polarisation • Resting neurons have Potential Difference Outer surface-> Positively charged Inner surface -> Negatively charged • Resting potential (-65mV), therefore said Polarised

  24. How does it work? • Resting potential is generated by Sodium-potassium pump and a potassium channel • The pump moves three sodium ions out by active transport for every two potassium ions brings in. • The facilitated diffusion allowed to let potassium ions back out. • More positive ions move out than move in.

  25. Depolarise when Stimulated • Sodium potassium pumps work all the time, but Channel protein can be opened or closed. • Depolarisation requires another protein channel, which is Sodium Channel. When Stimulated, sodium channel opens and then ions diffuses in. This increases the positive charge inside the cell. Charge is now Reversed. With a potential difference of +40mV, This is Action Potential and membrane is depolarised.

  26. Makes it much easier • http://www.youtube.com/watch?v=SCasruJT-DU

  27. Practice Questions • Q: What do sensory, relay and motor neurons do in the nervous system? • Answer: Sensory – INPUT Fromsensory organs to the brain and spinal cord. Relay – Interneurons carry information between other neurons only found in the brain and spinal cord. Motor – OUTPUTFrom the brain and spinal cord To the muscles and glands.

  28. Practice Questions • Q: Give two factors that increases the speed of conduction of action potentials • Answer: Bigger axon diameters Increase in temperature

  29. Bibliography • Notes from Richard • www.deafed.net/PublishedDocs/ • www.psych.wright.edu/Wayne/ • http://academic.luzerne.edu/ • http://en.wikipedia.org/wiki/Neuron • http://en.wikipedia.org/wiki/Action_potential • http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/bio%20102/bio%20102%20lectures/nervous%20system/neurons.htm

  30. Thank you for your attention THE END

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