Which is TRUE about the initial segment of an axon?
A. Its membrane potential at threshold is more positive than that of the cell body and dendrites.
B. Its membrane potential at threshold is more negative than that of the cell body and dendrites.
C. Synapses far from the initial segment are more effective in influencing whether an action potential will be generated in the axon than are synapses close to the initial segment.
D. It is the region where neurotransmitter vesicles are docked and ready to be released by exocytosis.
E. It can only conduct graded potentials because it lacks voltage-gated Na+ channels.
B
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Muscle contractions that generate less force than the resistance and result in lengthening of the muscle are called:
A. Eccentric contraction B. Concentric contraction C. Isometric contraction
The intensity of a stimulus can be determined within the central nervous system by
A) labeled line coding only. B) population coding only. C) labeled line coding and/or frequency coding. D) population coding and/or frequency coding. E) frequency coding only.
Which structure of the larynx vibrates to produce sound?
A) epiglottis B) vestibular ligaments C) tracheal rings D) vocal ligaments
Define excitability
What will be an ideal response?