Propagation of Action Potential and Synapses

These flashcards cover key concepts related to the propagation of action potentials along axons and synaptic transmission.

Action Potential

A transient change in electrical potential across a cell membrane that occurs when a neuron is activated.

Voltage Gated Channels

Proteins in the cell membrane that open or close in response to changes in voltage, allowing ions to enter or exit the cell.

Refractory Period

A period following an action potential during which a neuron is unable to fire another action potential.

Saltatory Conduction

A mode of conduction in myelinated axons where the action potential jumps from one node of Ranvier to the next, speeding up the transmission.

Continuous Conduction

The slow process of action potential propagation along unmyelinated axons where each segment of the membrane is depolarized in sequence.

Synapse

The junction between two neurons or between a neuron and a muscle cell where nerve signals are transmitted.

Calcium (Ca2+) Ions

Ions that enter the axon terminal during synaptic transmission, triggering the release of neurotransmitters.

Neurotransmitter

Chemical messengers released from a neuron that transmit signals to other neurons or muscles.

Myelin Sheath

A fatty substance that surrounds and insulates axons to enhance the speed of action potential transmission.

Presynaptic Neuron

A neuron that sends a signal to another neuron at a synapse.

Postsynaptic Neuron

A neuron that receives a signal from a presynaptic neuron at a synapse.

Nodes of Ranvier

Gaps in the myelin sheath of an axon where voltage-gated channels are concentrated.

Neuromuscular Junction

A synapse between a motor neuron and a muscle cell.

Absolute Refractory Period

A phase during which no additional action potential can be generated, regardless of the strength of the stimulus.

Relative Refractory Period

A phase during which a stronger-than-normal stimulus is required to generate a second action potential.

Dendrites

Branching extensions of a neuron that receive signals from other neurons.