Exam II - BIO4120 2008 EXAM II June 6, 1. _ are known as...

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BIO4120 June 6, 2008 EXAM II 1. _______________ are known as the functional unit of the nervous system. a. Glial cells b. Skeletal muscle c. Neurons d. Axons e. Dendrites 2. Which of the following regarding axons is NOT true. a. Their terminal ends can synapse directly with their effector cell (ie muscles or glands) b. They are designed to convey both chemical as well as electrical signals c. Except for the varicosities, their cytoplasm is rich in ribosomes and endoplasmic reticulum d. Their primary function is to transmit outgoing electrical signals from the integrating center of the neuron to the end of the axon e. They can vary in length from more than a meter to only a few millimeter 3. All of the following are glial cells of the nervous system except a. Chromaffin cells b. Satellite cells c. Schwann cells d. Ependymal cells e. Astrocytes
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4. Which of the following statements is NOT true? a. If a membrane is permeable to only one ion, then the resting membrane potential for that cell would be equal to the equilibrium potential for that ion b. The resting membrane of cells is much more permeable to potassium than sodium or calcium c. If a cell became more permeable to sodium, the membrane potential of the cell would become less negative so the cell would depolarize d. If a cell became more permeable to calcium, the membrane potential of the cell would become less negative so the cell would depolarize e. If a cell hyperpolarizes, its membrane potential becomes more positive 5. When Ca+2 ions enter the axon terminal, a. Exocytosis is initiated b. neurotransmitters are released to enter the synapse c. Cl- channels are triggered to open d. A and B e. A, B, and C 6. In which of the following would the rate of impulse conduction be the greatest? a. a myelinated fiber 20 microns in diameter b. a nonmyelinated fiber 20 microns in diameter c. a myelinated fiber 2 microns in diameter d. a nonmyelinated fiber 2 microns in diameter e. they would all be the same 7. Each of these statements is true except one. Identify the exception.
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a. recordings of action potentials show them to be identical depolarizations b. an action potential measured at the distal end of an axon is identical to the action potential measured at the trigger zone c. the strength of the graded potential that triggers the action potential is critical in determining the size of the action potential, especially if the graded potential is below threshold d. neither A nor B is true e. A, B, and C are true 8. The primary problem in hyperkalemia is that a. neurons are harder to excite because their resting potential is hyperpolarized b. neurons are hyperexcitable because their resting potential is closer to threshold c. neurons respond too quickly to smaller graded potentials d. A and C e. B and C 9. Which of these does NOT contribute significantly to the protection of the brain? a. cranium
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Exam II - BIO4120 2008 EXAM II June 6, 1. _ are known as...

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