NPB101_Bautista_Goldberg_Sp06_MT1_Key - NPB 101 Midterm...

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NPB 101 Midterm 1_2006 Answer Section MULTIPLE CHOICE 1. ANS: D The response is in a homeostatic loop will always counter the change that occurs within the system. It is designed to prevent significant change from the set point value. Generally, the set point is constant. DIF: Easy REF: Homeostasis 2. ANS: D Lowering the Na+ outside will decrease the driving force that pushes Na into a cell. This would decrease the magnitude of the equilibrium potential, but will not affect the resting membrane potential of the cell DIF: Hard REF: Membrane Potentials 3. ANS: A If the inactivation gate were removed, the current through the channel would not cease until the activation gate closed. This would not affect the opening of the voltage gated potassium channel, nor does it affect the resting membrane potential. Sodium flux into the cell will be unaffected. The greatest effect would be on the refractory period. The refractory period is induced by inactivation of the sodium channel. The frequency of stimulation is also related to inactivation; if a channel cannot be inactivated, then the neuron may be stimulated at a higher frequency than normal. DIF: Easy REF: Action Potential 4. ANS: D Myelination allows action potentials to travel quickly through the axonal processes. They do not decrease internal resistance, but they do increase membrane resistance of the axon. DIF: Easy REF: Myelination 5. ANS: D The composition of CSF is not identical to that of plasma. Its composition is influenced by transport processes that bring water soluible material into the ventricles via the choroid plexi epithelium. The only material that moves into the CSF are that which is lipid soluble, because that stuff easily moves through the plasma membrane of the endothelial cells and the ependymal cells. The CSF does not drain back into the blood at the blood brain barrier,
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This note was uploaded on 04/05/2012 for the course NPB NPB 101 taught by Professor Weidner/wingfield during the Spring '08 term at UC Davis.

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NPB101_Bautista_Goldberg_Sp06_MT1_Key - NPB 101 Midterm...

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