Module 2 Terminology

Question 1

Neurons

Answer 1

Principle cells of the nervous system responsible for processing and transmitting information

Question 2

Myelin

Answer 2

A thick, fatty substance that wraps around axons and serves as an insulator. Influences the speed of propagation of nerve impulses

Question 3

Synapse

Answer 3

A structure consisting of a presynaptic terminal bouton, a synaptic cleft, and a postsynaptic membrane

Question 4

Neurotransmitter

Answer 4

A chemical released by the axon into a synapse that either inhibits or excites the next neuron

Question 5

Resting potential

Answer 5

Potential difference of -70 millivolts that exists across the cell membrane when the neuron is is a resting state

Question 6

Depolarization

Answer 6

Change by which the inside of a neuron becomes less negatively charged (i.e., voltage becomes more positive inside)

Question 7

Hyperpolarization

Answer 7

Change by which the inside of a neuron becomes more negatively charged

Question 8

Graded potential

Answer 8

Changes in membrane potential that vary in size, as opposed to being all-or-none. Arises from the summation of the individual actions of ligand-gated ion channel proteins, and decrease over time and space.

Question 9

Action potential

Answer 9

Propagated wave of positivity and negativity that sweeps down the axon without decrement to the terminal boutons of the axon and its collaterals.

Question 10

Saltatory conduction

Answer 10

The “jumping” of an action potential from one node of Ranvier to the next node of Ranvier