What Is the Best Estimate of the Number of Neurons

question 12

Multiple Choice

What is the best estimate of the number of neurons in your brain?

• A) about 10 to 20 million
• B) several hundred million
• C) about 1 billion
• D) 10 to 99 billion
• E) at least 100 billion

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Definitions:

Excitation Threshold

The voltage difference between a neuron’s interior and exterior that, if exceeded, causes the neuron to fire.

Action Potential

A temporary reversal of electric polarization of the membrane of a nerve cell or muscle cell, involved in the transmission of signals.

Nodes of Ranvier

Gaps in the myelin sheath of nerve fibers that facilitate the rapid conduction of electrical impulses along the neuron.

Myelinated Neuron

A nerve cell that features a myelin sheath around its axon, enhancing the speed of electrical transmission of signals.