The Neuron and Synapse Flashcards

A set of practice flashcards covering neuron anatomy and the 10-step process of synaptic transmission as described in the lecture notes.

Dendrites

Receive incoming signals from other neurons and carry them toward the cell body.

Axon Hillock

Integrates signals from dendrites; decides whether to fire an action potential. Known as the neuron's "decision zone."

Schwann Cell

Produces the myelin sheath around axons in the peripheral nervous system. Supports and insulates the axon.

Axon Terminals

Release neurotransmitters into the synapse to communicate with the next neuron or target cell.

Cell Body (Soma)

Contains the nucleus; maintains the neuron's metabolism and integrates incoming signals.

Nodes of Ranvier

Gaps in the myelin sheath where the action potential is regenerated, enabling fast saltatory conduction.

Myelin Sheath

Insulates the axon to speed up electrical signal transmission and reduce energy loss.

Axon

Conducts the action potential away from the cell body toward the axon terminals.

Action Potential Arrives (Step 1)

The electrical signal reaches the axon terminal, triggering the neurotransmitter release process.

Voltage-Gated $Ca^{2+}$ Channels Open (Step 2)

Membrane depolarization causes calcium channels in the pre-synaptic membrane to open.

$Ca^{2+}$ Enters the Terminal (Step 3)

Calcium ions flood into the axon terminal, triggering synaptic vesicles to move toward the membrane.

Synaptic Vesicles Fuse (Step 4)

Vesicles dock with the pre-synaptic membrane and release neurotransmitters via exocytosis.

Autoreceptor (Step 5)

A pre-synaptic receptor that detects the neuron's own neurotransmitters to regulate further release (feedback control).

Neurotransmitter Released into Cleft (Step 6)

Neurotransmitters diffuse across the synaptic cleft toward post-synaptic receptors.

Neurotransmitter Binds to Receptor (Step 7)

NT binds post-synaptic receptors, causing ion channels to open and generating a new electrical signal.

Post-Synaptic Receptors (Step 8)

Receive neurotransmitters and convert the chemical signal back into an electrical one in the next cell.

Reuptake Transporter (Step 9)

Pumps neurotransmitters back into the pre-synaptic neuron for recycling (e.g., serotonin, dopamine transporters).

Enzyme Degradation (Step 10)

Enzymes in the cleft break down remaining neurotransmitters to terminate the signal (e.g., acetylcholinesterase).