1 Neurons and Neural Signaling Free Online FlashCards

What does neuroscience study?

Neuroscience studies how the nervous system receives, processes, and sends information.

What is the main role of neuronal dendrites?

Dendrites receive many incoming signals from other cells.

Where does an action potential commonly begin?

The axon initial segment is a common site where an action potential begins, if the membrane reaches threshold.

What is the resting membrane potential?

It is the voltage difference across the membrane at rest. The inside is usually negative relative to the outside, in part because the resting membrane is especially permeable to potassium ions.

What are graded potentials, and how can they combine?

Graded potentials are small, local changes in membrane voltage whose size depends on the input. They can add together across time or locations.

What characterizes an action potential?

It is a brief, all-or-none electrical event: sodium ions entering the cell rapidly depolarize the membrane, then sodium-channel inactivation and potassium ions leaving repolarize it.

How can a neuron represent a stronger stimulus?

A stronger stimulus generally does not make an individual action potential larger; stimulus strength can instead be represented by a change in firing rate.

What is the function of the refractory period?

The refractory period is a brief period after an action potential that helps limit immediate refiring.

How do nodes of Ranvier support rapid signal conduction?

In myelinated axons, the signal is regenerated at nodes of Ranvier, enabling rapid saltatory conduction.

How does an arriving action potential trigger neurotransmitter release?

An arriving action potential opens calcium channels in the axon terminal. Calcium entry triggers vesicles to release neurotransmitter into the synaptic cleft.

What determines a neurotransmitter's effect on a receiving cell?

A neurotransmitter's effect depends on the receptors and cellular context; it does not depend only on the transmitter's identity.

What are three functions of astrocytes?

Astrocytes help regulate ions and neurotransmitters around synapses, support neurons metabolically, and interact with blood vessels.