Membrane Potentials & Synapses

These flashcards cover key concepts related to membrane potentials and synapses, including definitions of various potentials, types of synapses, and principles of synaptic transmission.

Resting Membrane Potential (RMP)

The voltage difference across the neuronal membrane at rest, typically at -70mV.

Action Potential (AP)

A rapid, transient change in membrane potential that propagates along neurons.

Depolarization

A decrease in membrane potential (becoming less negative), indicating the inside of the membrane becomes more positive.

Hyperpolarization

An increase in membrane potential (becoming more negative), making it less likely to generate an action potential.

Graded Potential

Localized changes in membrane potential that vary in strength and can lead to action potentials.

Voltage-Gated Channels

Ion channels that open or close in response to changes in membrane potential, crucial for action potentials.

Sodium-Potassium Pump (Na+-K+ Pump)

A membrane protein that actively transports sodium out of and potassium into the cell, maintaining RMP.

Threshold

The critical level to which a membrane potential must be depolarized to trigger an action potential.

Propagation of Action Potential

The process by which an action potential moves along the axon, either continuously in unmyelinated axons or by saltatory conduction in myelinated axons.

Synapse

The junction between two neurons that facilitates communication through electrical or chemical signals.

Presynaptic Neuron

The neuron that sends the signal across the synapse.

Postsynaptic Neuron

The neuron that receives the signal at the synapse.

Chemical Synapse

A type of synapse that uses neurotransmitters to transmit signals from one neuron to another.

Electrical Synapse

A less common type of synapse where neurons are connected by gap junctions, allowing for rapid communication.

Excitatory Postsynaptic Potential (EPSP)

A postsynaptic potential that makes a neuron more likely to fire an action potential.

Inhibitory Postsynaptic Potential (IPSP)

A postsynaptic potential that makes a neuron less likely to fire an action potential.

Synaptic Integration

The process by which multiple synaptic inputs combine to influence the postsynaptic neuron.

Temporal Summation

The integration of multiple excitatory inputs that occur in rapid succession.

Spatial Summation

The integration of simultaneous inputs from multiple synapses.

Synaptic Potentiation

The increase in the efficiency of synaptic transmission following repeated stimulation.

Synaptic Delay

The interval between the arrival of an action potential at the axon terminal and the postsynaptic response.