A Recording Electrode Is Placed into a Nerve Cell to Measure

question 445

Multiple Choice

A recording electrode is placed into a nerve cell to measure the membrane potential at a particular point. When the physiologist glances at the recording and sees that the membrane at that instant has a potential of +15 mV, she knows that the portion of the membrane being recorded is which of the following?

• A)in the normal resting state
• B)in the reversal phase of an action potential when the inside of the cell becomes more positive than the outside
• C) more permeable to Ca²⁺ than normal
• D) in the after hyperpolarization phase of an action potential

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Definitions:

Blood-Brain Barrier

Specialized membranes that surround the blood vessels within the brain and filter harmful chemicals out of the brain’s blood supply.

Defense System

Mechanisms or strategies employed by individuals or systems to protect against threats, criticism, or psychological harm, often unconsciously in the form of psychological defenses.

Hyperpolarized

describes a state where a neuron's membrane potential becomes more negative than its resting potential, making it less likely to fire an action potential.

Transmitter Substances

Chemicals released by nerve cells to transmit signals across a synapse to another nerve, muscle, or gland cell.