Neural Cell Biology Flashcards
Slow anterograde Carries?
transports cytoskeletal proteins moving in polymerized form
Fast anterograde transport
Transports actin, myosin, other proteins, metabolic enzymes, second messenger molecules
Glia Roles in PNS and CNS
Radial Glia
Precursors of astrocytes that extend from ventricular to pial surface, provide substrate scaffolding that young neurons use in migration from ventricular zone to final location
Macroglia derived from
Microglia derived from
Neuroepithelium
Mesoderm
Microglia Characteristics
divide promptly in response to brain injury
involved in inflammatory response in CNS
serve macrocytic functions. Scavenge cellular debris
Macroglia two types
astrocytes and oligodendrocytes
Astrocyte function
metabolic/trophic support of neurons, modulation of synaptic transmission
Astrocyte Molecule Buffering
buffer potassium in extracellular space. Take up excess potassium and chloride when axons are active to prevent nearby axons from depolarizing.
Astrocyte Signaling
Astrocytes can communicate with one another via gap junctions
Large Myelinated Axon = (In terms of electical signaling)
Low resistance and low capacitance to send more signal with less loss to next node of ranvier
Charcot-Marie-Tooth
Inhibitory synapses generally located on
axo-somatic synapses
excitatory synapses often located on
dendrites or dendritic spines (axo-dendritic)
presynaptic termianl function - lambert eaton myasthenic syndrome affects
Presynaptic Terminal - Botulinum tetanus toxin affects
Differences in decision to fire AP in CNS and PNS
Importance of axon hillock/trigger zone
Determiens if the electrical signal sum provided to that neuron is enough to signal an action potential
Membrane Time Constant
The longer the time constant the longer the potential lasts and greater extent of temporal summation
Axon Length Constant
Relates to efficiency of current - affecting degree to which depolarization current decreases passively as it spread. Long length constant means minimal loss of signal
3 Synaptic Types and differences in active zone size
2 Methods of presynaptic inhibition and facilitatoin
Inhibition = open K close Ca
Wallerian Degeneration General
Axon Injury effect on Nissl substance
In PNS after injury cell body gears up to grow axon back and new material pushes Nissl substance to edges of soma
CNS Wallerian: What happens to debris compared to PNS
In PNS cleared in days. in CNS debris persists for much longer
gliosis
after injury, glia cells induced to divide to form a scar around damaged regions.Prevents regrowth but contains damage.
3 Factors that inhibt regeneration in CNS
Who eats debris PNS vs CNS
Are other neurons affected
Macrophages in PNS, Microglia in CNS
In CNS connected neurons affected.
