Neuron-Glia Plasticity Flashcards
Name a few functions of the glia-cells
- Maintain structure
- Repair tissue framework
- Perform phagocytosis
- Provide nutrients to neurons
- Regulae composition of the interstitial fluid
What kind of Glial cells are found in the Peripheral Nervous system? Explain their function
- Satellite cells - support structure of cell bodies of the nervous system
- Schwann cells - they form myelin around axons in the peripheral nervous system
What kind of Glial cells are found in the Central Nervous system? Explain their functions.
- Ogliodendrocytes - form myelin around axons in the CNS
- Astrocytes - support the structure of the nervous system, secrete nutrients, clear up waste
- Microglia - Scavenger cells (modified immune cells)
- Ependymal cells - create barriers between compartments
How do oligodendrocytes help with neuron plasticity?
They myelinate the axons, leading to a faster signal transduction
How can one possibly fine-tune signal velocity in neurons?
- Thickness of myelin sheets (electric isolation)
2. Length between nodes (internodes)
What two proteins are crucial for myelin formation in the early stages of development?
NRG1 Type III - produced by axons
ErbB2/B3 - produced by the Schwann cells
They both interact and the Schwann cell wraps around the axons that express NRG1 Type III proteins
Why do large axons get once Schwann to wrap around the circumference while smaller neurons are present in non-myelinated bundles?
Because larger axons produce more NRG1 Type III so the Schwann cells will have a stronger signal to bind to them.
what is the difference between Intrinsic and Developmental myelination?
Intrinsic myelination is the initial amount of myelin that the body produces, without any other influence than genetics.
Developmental myelination is when more myelin is getting produced, depending on the neuronal activity.
Why does the synaptic cleft appear so dark in electron-microscope pictures?
Because of the dense amount of proteins to measure the amounts of neurotransmitters.
What is a Tripartite Synapse composed of?
A pre-synaptic cell, a post-synaptic cell, and an astrocyte.
How do astrocytes communicate with each other?
Astrocytes communicate via calcium wave signals, but it is very slow, compared to neurons.
Why do Astrocytes wrap a synapse?
To prevent any substances (like glutamate) from leaking out
How does a synapse wrapped by an astrocyte affect another synapse further away?
The astrocytes release calcium upon activation by Glutamate. The calcium wave is then transported through cellular junctions and other cells release calcium as well, increasing the excitability of a synapse further away from the initial signal.
Do astrocytes respond to other neurotransmitters than glutamate?
Yes, they can react to many other neurotransmitters and elevate the calcium in the cell.
Do astrocytes integrate information?
Yes, they somehow integrate information. This has been observed in a deviation of expected calcium signaling - as it was different than initially thought. (more research needed)
