#1 In the process of saltatory action potential propagation A) the action potent
ID: 163269 • Letter: #
Question
#1 In the process of saltatory action potential propagation
A) the action potential is triggered by graded depolarization of the initial segment.
B) at threshold, sodium channels begrn to open rapidly.
C) local currents depolarize the region just adjacent to the active zone.
D) local currents depolarize a sensitive spot distant from the active zone.
E) A, B, and D
#2 which of the following statements about the action potential is false?
A) The rapid depolarization phase is caused by the entry of potassium ions.
B) During the depolarization phase, membrane potential becomes positive.
C) During the repolarization phase, sodium channels close and potassium channels open.
D) In the after-hyperpolarization phase, membrane potential approaches the potassium
equilibrium potential.
E) None of these statements is false-all are true.
#3 Cerebrospinal fluid flows with the
A) pia mater
B) dura mater
C) filum terminale
D) arachnoid mater
E) subarachnoid space
#4 Parkinson disease is the result of
A) inadequate production of dopamine by substantia nigra neurons.
B) inadequate production of GABA by neurons in the basal nuclei.
C) weak response of the red nuclei of the mesencephalon.
D) decreased levels of acetylcholine from neurons in the substantia nigra.
E) hyperactivity of the limbic system
#5 Nicotinic receptors
A) are found at neuroeffector iunctions of the parasympathetic nervous system.
B) respond to epinephrine.
C) open dremically gated sodium ion charurels.
D) open dremically gated calcium ion drannels.
E) respond to norepinephrine.
#6 Which of the following is a function of a neuroglia?
A) produce cerbrospinal fluid
B) provides a supportive framework
C) regulate the compostion of interstitial fluid
D) act as phagocytes
E) All of the above
Explanation / Answer
2-a) The rapid depolarization phase is caused by the entry of potassium ions.
3-d) subarachnoid space
4-a) inadequate production of dopamine by substantia nigra neurons
5-c) open chemically gated sodium ion channels
6-d) act as phagocytes
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