Neuroscience: Neurons, Synapses, and Vesicle Cycling (Vocabulary)

Vocabulary flashcards covering nerve structure, glial support, visualization techniques, synaptic transmission, vesicle cycling, and pain modulation from the lecture notes.

Neuron doctrine

Idea that neurons are discrete functional units that communicate via synapses rather than forming a continuous network.

Bipolar neuron

A neuron with two processes (dendrite and axon) with the soma between; a basic example of neuronal structure.

Dendrite

Input region of a neuron that receives signals from other neurons.

Soma

Cell body of a neuron containing the nucleus and organelles.

Axon

Output projection that conducts action potentials away from the soma.

Axon hillock

Region at the start of the axon where action potentials are initiated.

Pre-synaptic terminal

End of the sending neuron's axon where neurotransmitters are released.

Post-synaptic terminal

Region on the receiving neuron with receptors for neurotransmitters.

Chemical synapse

Synapse where neurotransmitters cross the synaptic cleft to signal the next neuron.

Electrical synapse

Fast, bidirectional synapse using gap junctions to pass ions directly.

Gap junction

Channel between adjacent cells allowing direct electrical coupling.

Connexins

Protein subunits that form gap junction channels in electrical synapses.

Golgi staining

Silver-based staining method to visualize individual neurons and their processes.

Nissl staining

Staining of rough endoplasmic reticulum (Nissl bodies) in neuron cell bodies.

Purkinje cell

Large, highly dendritic cerebellar neuron illustrating neuronal diversity.

Astrocyte

Glial cell that recycles neurotransmitters (e.g., glutamate) and modulates synaptic communication.

Oligodendrocyte

CNS glial cell that forms the myelin sheath around axons.

Schwann cell

PNS glial cell that myelinates peripheral axons.

Microglia

CNS immune cells involved in defense and inflammatory responses.

Myelin

Lipid-rich sheath around axons that increases conduction speed.

White matter

CNS region rich in myelinated axons.

Gray matter

CNS region rich in neuronal cell bodies and dendrites.

Afferent

Information or signals moving toward the CNS (sensory pathways).

Efferent

Information or signals moving away from the CNS (motor pathways).

Anterograde transport

Movement of cargo from the soma toward the axon terminals.

Retrograde transport

Movement of cargo from axon terminals back to the soma.

Five senses

Sight, hearing, smell, taste, and touch processed by the brain.

Somatosensory cortex

Parietal lobe region processing touch, temperature, and pain.

Occipital cortex

Cortex responsible for visual processing.

Temporal lobe

Lobe involved in emotion, memory, learning, and auditory processing.

Frontal lobe

Lobe important for executive functions and decision-making.

Parietal lobe

Lobe involved in somatosensory processing and spatial body awareness.

CNS

Central nervous system: brain and spinal cord.

PNS

Peripheral nervous system: all nerves outside the CNS.

Tract

Bundle of axons in the CNS forming neural pathways.

Olfactory bulb

Brain structure involved in the sense of smell.

Nociception

Detection of potentially harmful stimuli by sensory neurons.

Pain

Perception of noxious stimuli; modulated by brain and spinal mechanisms.

Descending pain modulation

Brain pathways that dampen or enhance pain signals at the spinal cord.

Spinal gate

Concept that the spinal cord modulates transmission of pain signals.

Endocannabinoids

Endogenous cannabinoids that modulate presynaptic release via GPCRs.

CB1 receptor

G-protein-coupled receptor for endocannabinoids, mainly in the CNS.

Retrograde signaling

Post-synaptic signals that travel back to the presynaptic terminal to modulate release.

SNARE complex

Protein machinery (v-SNAREs and t-SNAREs) mediating vesicle fusion.

Synaptobrevin (VAMP)

Vesicle-associated SNARE protein essential for fusion.

SNAP-25

Target SNARE protein on the plasma membrane involved in fusion.

Syntaxin

Target SNARE protein on the plasma membrane involved in fusion.

Synaptotagmin

Calcium sensor on the vesicle that triggers vesicle fusion.

CaMKII

Calcium/calmodulin-dependent protein kinase II; promotes vesicle mobilization.

Synapsin

Protein that tethers vesicles to the actin cytoskeleton to regulate mobilization.

Rab GTPases

Family of small GTPases guiding vesicle docking at the presynaptic membrane.

RIM protein

Rab-interacting molecule involved in docking at the active zone.

Munc13

Protein essential for priming vesicles for fusion.

Clathrin

Protein forming a coated vesicle during endocytosis.

Dynamin

GTPase that nips off clathrin-coated vesicles during endocytosis.

Endocytosis

Process of vesicle membrane retrieval after exocytosis.

Exocytosis

Vesicle fusion with the presynaptic membrane to release neurotransmitters.

EPP

Endplate potential; evoked postsynaptic depolarization at the NMJ.

Mini EPP (mEPP)

Spontaneous miniature endplate potential from single vesicle release.

Quantal release

Neurotransmitter release in discrete packets corresponding to vesicle content.

Botulinum toxin

Toxin that cleaves SNARE proteins, blocking neurotransmitter release.

Myasthenia gravis

Autoimmune disease with antibodies against acetylcholine receptors at the NMJ.

NMJ

Neuromuscular junction; synapse between motor neuron and muscle.

End plate

Postsynaptic region of the muscle fiber at the NMJ.

HRP

Horseradish peroxidase used as a tracer to study vesicle cycling.

Dense-core vesicles

Vesicles carrying neuropeptides; larger and less Ca2+-sensitive than small clear vesicles.

Small clear vesicles

Vesicles carrying classic neurotransmitters like glutamate, GABA, or acetylcholine.

Glutamate

Major excitatory neurotransmitter in the brain.

GABA

Major inhibitory neurotransmitter in the CNS.

Acetylcholine

Neurotransmitter at many synapses, notably the NMJ.

Dopamine

Biogenic amine important for reward, movement, and motivation.

Serotonin

Biogenic amine involved in mood, appetite, and cognition.