CNS and Cell Types Flashcards
Where do action potentials originate?
The axon hillock
Where do inputs to cells come from?
Dendrites
Where do outputs from cells go?
Through axons
What are the 2 types of synapses?
Electrical
Chemical (majority)
Where are excitatory synapses concentrated?
On dendritic spines
What neurons are lost in Motor Neuron Disease?
Motor neurons
What neurons are lost in Huntington’s Disease ?
Medium spiny GABA neurons
What is an upper motor neuron?
first-order neurons which are responsible for carrying the electrical impulses that initiate and modulate movement.
They are large, excitatory neurons which are glutaminergic and have long projection pyramidal cells
What are striatal interneurons?
Small, inhibitory GABAergic neurons
What are oligodendrocytes?
Myelinating cells of the CNS (the PNS has schwann cells which are myelinating)
They insulate axon segments are allow rapid nerve conduction
Provide metabolic support for axons
Myelin sheath segments are interrupted by nodes of ranvier- part of neurotransmission where the impulse travels along the axon
A single oligodendrocyte can myelinate multiple axons
What is the myelin sheath?
Formed by wrapping of axons by oligodendocyte processes
They are highly compacted
Myelin specific proteins cna be used as ‘markers’
What are microglia?
Resident immune cells of the CNS
Proliferate at sites of injury
Upon acitvatio, retract processes and become “amoeboid” and motile
What are the functions of microglia?
Immune surveillance
Phagocytosis- debris/microbes
Synaptic plasticity- pruning
Good (M2) glia and bad (M1) glia
What are astrocyes?
Star like cells
Most numerous glial cells in the NCS
Part of the BBB
What is the function of astrocytes?
Envelop synapses & blood vessles
Metabolic support
NVC
Proliferate (increase) in disease
Development
Regulate ion/metabolites