Neurons communicate within themselves through electrical changes across their membranes. This lesson explains how ion distributions create the resting membrane potential and how a sufficiently strong input triggers an action potential.
A neuron's lipid membrane separates the fluid inside the cell from the fluid outside it. Charged particles called ions cannot pass freely through the lipid bilayer; they cross through specialized membrane proteins called ion channels. Some channels open or close in response to changes in voltage and are called voltage-gated ion channels.
All flashcards
How does the sodium-potassium pump help maintain neuronal ion gradients?
Using one ATP molecule, it moves three sodium ions out and two potassium ions in.
What is saltatory conduction?
Action-potential propagation along a myelinated axon by regeneration at successive nodes of Ranvier.
How does calcium trigger neurotransmitter release at a chemical synapse?
Calcium entry into the presynaptic terminal triggers synaptic vesicles to fuse with its membrane and release neurotransmitter.
How does an electrical synapse transmit signals?
Gap junctions allow electrical current to pass directly between connected cells.
How does long-term depression affect a synapse in one described mechanism?
It removes AMPA receptors from the postsynaptic membrane, weakening the response to glutamate.
Quiz questions
How does myelin generally affect action-potential conduction along an axon?Answer: It reduces current leakage and increases conduction speed.
Why does the refractory period help an action potential travel forward along an axon?Answer: Recently activated membrane is temporarily unable to fire again, while membrane ahead can be stimulated.
What is the effect of an inhibitory postsynaptic potential (IPSP)?Answer: It makes the postsynaptic cell less likely to reach firing threshold.
How does summation influence whether a neuron fires an action potential?Answer: The combined effect of excitatory and inhibitory inputs determines whether threshold is reached.
What does a brain-computer interface do?Answer: It decodes recorded brain activity to control an external device.
Based on Biology 2e by Mary Ann Clark, Matthew Douglas, Jung Choi (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.