Neuro: Neurons, Glia, Histology Flashcards
Soma is the:
Cell body of the neuron
Soma is involved in:
-gene expression
-biosynthesis
-cell. Survival mechanisms
-responses to injury
-receives synaptic input
Dendrites:
-“fingers”
-receive synaptic input
-can be structurally altered by activity
Axons:
Send out action potential that initiates at the axon hillock
Terminals:
Where axons send their information to, and terminals release neurotransmitter into synapses
Terminal boutons
Site of release of synaptic vesicles and neurotransmitters into synaptic cleft
In the terminal bouton, neurotransmitter molecules are stored inside ______________
Synaptic vesicles
When an action potential reaches the terminal…
The vesicles fuse with the cell membrane, releasing the stored neurotransmitter into the synaptic cleft where it binds to receptor in cell mem. of postsynaptic neuron
Post-synaptic density:
Appearance of the synapse region by electron microscopy
In the resting state of pre-synaptic activation:
-few vesicles are already docked at active zone, not yet fused
-most vesicles tethered by actin and not docked
In the activated state of presynaptic activation:
-Ca2+ influx allows neurotransmitter release by pre-docked vesicles
-Ca2+ influx causes actin filaments to dis-associate from vesicles
Axon terminals can form synapses on what part of the neuron?
Any part!
Synapses can mediate either excitatory or inhibitory effects on the post-synaptic neuron. This depends on:
-nature of neurotransmitter
-nature of the receptor for that neurotransmitter
Synapses on dendritic spines are…
ALWAYS excitatory
At axoaxonic synapses, neurotransmission can excite or inhibit the…
Postsynaptic axon terminal s
Sensory/pseudo-unipolar neurons :
-Touch/pain receptors in skin/viscera and taste receptor cells
-Typically located in a ganglion
Motor neurons are located in:
Located in the anterior horn of the spinal cord and in cranial nerve motor nuclei in brainstem
Local interneuron
Usually very short, unmyelinated axons in PNS and CNS
Neuroendocrine neuron
-Mostly in hypothalamus
-release peptide hormone into blood (systemic or portal circulation
Antrograde axonal transport:
-from cell body to terminals
-synaptic vesicles
-neurotransmitters, synthetic enzymes
Retrograde axonal transport:
-from terminals to cell body
Kinesin is ____________ because it goes toward _____ end
Anterograde, plus end
Dynein is ______________ because it goes towards ______ end
Retrograde, minus
Clinical significance of axonal transport:
-pathophysiological role in neurodegenerative disorders
-role in viral infections of PNS
-potential tool for viral delivery of gene therapy