BIOL 3800 1st Edition Lecture 7 Outline of Current Lecture I. Pop Quiz Discussion Questions and AnswersII. Communication Along and Between NeuronsA. Transmission of Information in a Single NeuronIII. Conduction Velocities and HistoryA. Helmholtz 1845B. Average Fiber Diameter…Current LectureChapter 6: Part I Communication along and Between MembranesI. Pop Quiz Discussion Questions and Answers1. Myelin is made by astrocytes in the central nervous system. False (Made by oligodendrites and Schwann Cells)2. Diffusion is a passive transport that requires neither ATP nor thermal energy; it is only concentration dependent. False3. During the rising phase of the action potential, the sodium current stops when the membranepotential reaches zero. False4. The bond between carbon and oxygen atoms in an amino acid molecule is approximately 5 kcal/mol.False5. Glia cells cannot make action potentials because they do not have membrane potentials. False(all cells have membrane potentials)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.6. For mammalian cells, a 240 milliosmolar salt solution is hypotonic. True7. Saturated fats contain no double bonds in their carbon chain. True8. Gap junctions also can serve as electrical synapses. True9. Gap junction allows the passage of molecule up to a maximum of 150 daltons. False10. After sodium has entered during the action potential, the Na+/K+ pump brings the membrane potential back to the normal negative resting level. False11. Graded potentials are NEVER self-propagating. True12. Movement of ions during the action potential occur mostly through the sodium pump protein. False 13. In order for the voltage-gated channel to open ATP must be hydrolyzed. False (not ATP dependant)14. Artificial kidneys work primarily via a process called dialysis. Which mode of membrane transport is responsible for dialysis?(a) ATP-dependent transport (b) diffusion transport (c) pressure transport (d) electrical gradient transport (e) active transportAnswer: B15. What is the classification of the water-water bond that dominates during the formation of ice?(a) Covalent bond (b)ionic bond (c) Van der Waals bond (d) hydrogen bond (e) none of the aboveAnswer: DI. Communication along and Between NeuronsA. Transmission of Information in a single neuron1. Must understand difference between passive and active processes2. So think Professor Gross in class his voice decays with distance so that in the backpeople can’t hear him as easily as those in the front who are closer to him- passive3. If you wanted to make action potential out of this scenario or active propagation then we would have a microphone at the back and a loudspeaker and another microphone 200 yards away and you could go to LEWISVILLE that way!!! a. This example of reamplification is what action potential does b. It is self-propagating and velocity depends on two factors.i. The diameterii. And myelinationII. Conduction Velocities and HistoryA. Helmholtz 18451. At one time everyone thought if something is electrical will move fast. No way to measure that in those days 2. In 1845 Helmholtz did experiment where he showed: a. AP propagation velocity and reason why slower than electrons b. Reason was because it was not carried by electrons but by massive ions i. ions much more weight than electrons so ionic phenomenon not electric or electronic phenomenon3. When did we find out which ions move across membranes? a. 1950’s Hodgkin Huxley 100 years later took a long timeB. Average fiber diameter… 1. people still arguing as to whether what B fibers supposed to be and subdivided A fibers and that’s just people messing around trying to make sense of things a. think representative diameter of 20 micrometers can get velocity or speed of 50 meters per second Not speed of light but it’s okay! b. C fibers tiny unmyelinated fibers you WILL NEVER SEE C FIBERS WITH MYELIN SHEATHa. conduct very low speeds and very vulnerable to low oxygen and low glucose you may not be dead but approaching it b. C fibers cut out don’t have volume Krebs cycle mitochondria etc. to survive membrane potential under these conditions that’s why you feel pretty good before you