Final Exam Information (NEW STUFF)

Final Exam Information (NEW STUFF) - 1064-1086 I. Neuron...

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1064-1086 I. Neuron structure a. Cell body b. Dendrites i. Part of the neuron that is going to receive information c. Axon d. Axon hillock e. Myelin Sheath (some) a. Electrical production – 2,074,000 kilowatts b. Is the water next to Hoover Dam high or low? i. High on one side and low on another side c. What allows the dam to produce power? d. What would change the capacity of the dam to produce power? i. Dam does work by Potential Difference ii. How much work can be done is the size of the gradient III. Membrane potentials a. All cells have an electrical gradient or electrical potential across their cell membrane. b. Measured with outside being = 0 (reference point) c. The inside is generally -50 to -100 milliVolts (mV) d. Elements i. High [] Na+ outside
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ii. High [] K+ inside iii. High [] organic molecules (-) inside iv. Na-K pumps ions unequally 1. 3 Na+ out for every 2K+ a. these concentrations aren’t exactly equivalent vi. Result 1. Fewer positive charges on the inside 2. More positive charges on the outside 3. Overall has a negative charge at about -70mV e. How could you change the membrane potential? i. You could reduce the gradient by moving Na into the cell. You don’t have to pump it because it can be diffused inside once membrane is permeable to Na. ii. Or I could make K permeable to the membrane and this will also diffuse itself. IV.Action Potentials a. All cells have membrane potentials b. Muscle and nerve cells are excitable. This means they can generate a change in membrane potential. V. Gated channels a. Excitable cells (muscles & neurons) have a special ion channel called ion gated channels. These are facilitated diffusion channel proteins that are embedded in the cell membrane letting specific ions going through. These gates can be opened or closed with Na gated channels and K gated channels.
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b. A stimulus will cause a change in gated channels c. If K+ channels open, what happens? i. They would like to flow out the cell because there’s more inside than outside so it wants to diffuse. ii. To the membrane potential, this will cause a more negative charge. 1. Hyperpolarization d. If Na+ channels, what happens? i. It becomes less negative, depolarization. VI.Action potential a. If a depolarization is great enough (threshold) it will stimulate an action potential b. This involves voltage-gated channels VII. Voltage gated channels a. Na+ b. K+ c. Differ: i. Ions allowed to pass ii. Speed of gate opening/closing iii. Number of gates d. Na+ Channels – 2 gates i. Activation gate = opens fast ii. Inactivation gate = closes slowly 1. Both gates start moving at the same time
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e. K+ Channels – 1 gate i. Opens slowly VIII. Action potential a. Is the result of a rapid depolarization of the membrane (NA+ activation gate open).
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This note was uploaded on 02/26/2009 for the course BIOL 1201 taught by Professor Wishtichusen during the Fall '07 term at LSU.

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Final Exam Information (NEW STUFF) - 1064-1086 I. Neuron...

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