Chapter 7 – Neural Physiology Key Points

A concise set of flashcards covering threshold potentials, synapse types, neurotransmitter classification, neural circuit patterns, and distinctions between upper and lower motor neurons.

Why will a postsynaptic neuron at −60 mV not fire an action potential?

Because −60 mV is below the threshold potential of −55 mV, so voltage-gated Na⁺ channels do not open to initiate an action potential.

Which type of synapse is typically involved in presynaptic inhibition or presynaptic facilitation?

An axoaxonic synapse.

Why are norepinephrine, epinephrine, dopamine, and serotonin classified as biogenic amines?

They are derived from amino acids that have been chemically modified.

A motor neuron receiving input from several other neurons is an example of what neural circuit pattern?

Convergence.

What is an "upper motor neuron," and why is the term a misnomer?

An upper motor neuron is an interneuron located entirely within the CNS that regulates lower motor neurons; it is called a motor neuron even though it does not directly innervate muscle, making the term technically inaccurate.

What is a "lower motor neuron"?

A true motor neuron that originates in the lower part of the CNS and conveys action potentials to skeletal muscle fibers in the periphery.