A sodium Na B potassium K C chloride Cl D calcium Ca E phosphate PO 4 Answer B

A sodium na b potassium k c chloride cl d calcium ca

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A) sodium (Na + ) B) potassium (K + ) C) chloride (Cl - ) D) calcium (Ca ++ ) E) phosphate (PO 4 - ) Answer: B 96) The resting membrane potential is close to the equilibrium potential of which of the following ions? A) sodium (Na + ) B) potassium (K + ) C) chloride (Cl - ) D) calcium (Ca ++ ) E) phosphate (PO 4 - ) Answer: B 97) During the rapid depolarization phase of an action potential, the plasma membrane is more permeable to which of the following ions? A) sodium (Na + ) B) potassium (K + ) C) chloride (Cl - ) D) calcium (Ca ++ ) E) phosphate (PO 4 - ) Answer: A 98) Increased permeability to what ion is responsible for the relative refractory period? A) sodium (Na + ) B) potassium (K + ) C) chloride (Cl - ) D) calcium (Ca ++ ) E) phosphate (PO 4 - ) Answer: B 18
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99) Effector organs act as receptors that detect information about the external environment and transmit that information to the central nervous system. Answer: True False 100) Excitable cells are capable of producing action potentials. Answer: True False 101) Generation of new neurons (neurogenesis) cannot occur in the brain. Answer: True False 102) Leak channels are most concentrated in the soma of neurons. Answer: True False 103) Afferent neurons are generally bipolar neurons. Answer: True False 104) Oligodendrocytes are located in the peripheral nervous system, providing the myelin sheath that forms the nodes of Ranvier. Answer: True False 105) Schwann cells are the only glial cells in the peripheral nervous system. Answer: True False 106) The number of ions whose movement across the membrane creates the resting membrane potential is so few that their movement does not affect that ion's concentration gradient. Answer: True False 107) The membrane potential of a cell is determined exclusively by that cell's sodium and potassium permeability. Answer: True False 108) At the resting membrane potential, a cell is at equilibrium. Answer: True False 109) The Na + /K + pump distributes three sodium ions to the outside of the membrane and two potassium ions to the inside of the membrane. Answer: True False 110) An ion's net electrochemical force will tend to move that ion across the membrane in a direction that will cause membrane potential to move toward that ion's equilibrium potential. Answer: True False 111) The Na + /K + pump maintains the concentration gradients in a neuron but maintains them. Answer: True False 112) Graded potentials are of equal magnitude and travel over long distances along the axon. Answer: True False 19
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113) In temporal summation, stimuli from different sources are applied at the same time such that they overlap and sum. Answer: True False 114) Excitatory graded potentials are those where the stimulus initiates a hyperpolarization of the cell. Answer: True False 115) Under resting conditions, the sodium channel responsible for generating an action potential is closed and incapable of opening. Answer: True False 116) Both activation and inactivation gates of a sodium channel are stimulated at the same time by a depolarization with the inactivation gate acting more slowly than the activation gate, thereby allowing sodium to enter the cell.
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