Local passive current flow decreases with distance because
a. ion pumps which drive current flow run out of energy (ATP) as they drift from the stimulus site.
b. current leakage across the membrane attenuates current available for intracellular current flow.
c. as it gets away from the active zone, the membrane fluidity decreases and prevents influx of booster current.
d. of all of these reasons.
e. of none of these reasons.
B
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Antagonists are compounds that
A) Prevent synthesis of new receptors. B) Prevent synthesis of hormones. C) Bind to a receptor, activating it. D) Bind to a receptor, but do not activate it.
Cells responsible for the secretion of calcitonin are located
A. on the posterior surface of the thyroid gland. B. between the follicles and among the cells that make up the follicle of the thyroid gland. C. within thyroid follicles. D. None of the choices are correct.
An electroencephalogram measures
A. electrical activity in the brain. B. the use of glucose in the brain. C. the production of CSF in the brain. D. blood flow in the brain.
The cascade of events in the intrinsic pathway can be set into motion when ________ comes into contact with collagen.
A. factor VII B. factor III C. factor XII D. calcium E. factor X