Neuron Structure and Function Quiz

Study Notes

Neurons are the fundamental units of the nervous system, responsible for transmitting signals.
Key components of a neuron:
- Soma (cell body): Contains the nucleus and organelles for cell metabolism.
- Dendrites: Receive signals from other neurons.
- Axon: Transmits signals away from the cell body.
- Axon terminals (postsynaptic terminals): Neurotransmitter release occurs here.
- Myelin sheath: Protects and speeds up signal transmission along the axon.
- Nodes of Ranvier: Gaps in the myelin sheath, allowing for faster signal propagation.

Multipolar neuron: Has multiple dendrites and one axon, common in the central nervous system (CNS).
Bipolar neuron: Found in sensory organs, has one dendrite and one axon.
Interneurons: Connect other neurons within the CNS.

Oligodendrocytes: Myelin sheath formation in the CNS.
Astrocytes: Provide support, regulate neurotransmitters, and maintain ion balance.
Microglia: Immune cells, clearing debris in the brain.

Depolarization: Na+ ions enter the neuron, making the inside more positive.
Repolarization: K+ ions flow out, restoring the negative charge inside the neuron.
Resting membrane potential: Stable, negative charge inside a neuron, typically -70mV.
Refractory period: A period following an action potential when the neuron cannot fire again.
Threshold: The minimum stimulation level required to trigger an action potential.
All-or-nothing events: Action potentials fire fully once the threshold is reached, or not at all.
Action potential propagation: Moves in a wave-like manner along the axon, jumping between Nodes of Ranvier in myelinated axons.

Synaptic Transmission: The process of signal transfer from one neuron to another at the synapse.
Excitatory signals: Bring the next neuron closer to firing.
Inhibitory signals: Reduce the likelihood of firing.
Synaptic plasticity: The ability of synapses to strengthen or weaken over time based on activity, crucial for learning and memory.

Ligand-gated ion channels: Open in response to the binding of specific molecules like neurotransmitters.
Ion pumps: Use ATP to transport ions against their concentration gradients, maintaining the resting membrane potential.
Leakage channels: Always open, allowing ions to passively move across the cell membrane.

Saltatory conduction: The process where action potentials jump from node to node along a myelinated axon.
Cytoskeleton components: Microtubules, neurofilaments, and microfilaments, providing structural support and maintaining the shape of the neuron.