white matter ARTICLE (mini-quiz 3) Flashcards
Myelination of the Nervous System: Mechanisms and Functions
What is the primary function of white matter in the central nervous system (CNS)?
White matter facilitates rapid communication between different brain regions by allowing the fast transmission of nerve impulses along myelinated axons.
Which cells are primarily responsible for producing myelin in the CNS?
Oligodendrocytes.
What is myelin and what role does it play in the CNS?
Myelin is a fatty sheath that insulates axons, speeding up the transmission of electrical signals in the nervous system.
How does myelination affect axonal conduction?
Myelination enables saltatory conduction, where electrical impulses jump from one node of Ranvier to the next, significantly increasing conduction speed.
What protein is critical in the CNS myelin membrane and has both structural and signaling roles?
Myelin basic protein (MBP).
What role does cholesterol play in myelin integrity?
Cholesterol is essential for myelin membrane structure, helping maintain the compact, insulating layers necessary for proper nerve conduction.
Name the gaps in the myelin sheath that are critical for the propagation of action potentials along the axon.
Nodes of Ranvier.
What is the function of proteolipid protein (PLP) in CNS myelin?
PLP helps maintain the stability and compactness of the myelin sheath.
What are oligodendrocyte progenitor cells (OPCs) and why are they important?
OPCs are precursor cells that differentiate into oligodendrocytes, which are crucial for myelination in the CNS.
What is the difference in myelin formation between the CNS and the peripheral nervous system (PNS)?
In the CNS, oligodendrocytes myelinate multiple axons, whereas in the PNS, Schwann cells myelinate individual axons.
Which factors can stimulate the differentiation of OPCs into mature oligodendrocytes?
Neural activity, growth factors, and extracellular matrix cues can promote OPC differentiation and myelination.
How does myelination adapt to an individual’s learning or motor activities?
Activity-dependent myelination occurs, where tasks like learning or motor skills training can increase myelin production and adjust myelin structure.
How does social isolation impact myelination?
Social isolation has been shown to reduce myelination in certain brain regions, potentially affecting cognitive and emotional functions.
What are leukodystrophies?
Leukodystrophies are a group of genetic disorders that primarily affect the white matter, leading to abnormal myelination and neurological deficits.
Describe Pelizaeus-Merzbacher disease (PMD) and its cause.
PMD is a leukodystrophy caused by mutations in the PLP1 gene, resulting in hypomyelination and progressive neurological impairment.
How does multiple sclerosis (MS) affect white matter?
MS is an autoimmune disease that leads to the demyelination of axons in the CNS, impairing signal transmission and causing various neurological symptoms.
Which transporter is important for transferring lactate from oligodendrocytes to axons, supporting axonal energy needs?
Monocarboxylate transporter 1 (MCT1).
What is the role of myelin-associated glycoprotein (MAG) in the CNS?
MAG is involved in stabilizing myelin-axon interactions and supporting axonal integrity.
Explain the significance of connexins in myelination.
Connexins are proteins that form gap junctions, facilitating intercellular communication between oligodendrocytes and between oligodendrocytes and astrocytes.
How do extracellular matrix molecules like chondroitin sulfate proteoglycans (CSPGs) affect myelination?
CSPGs can inhibit myelination by creating a physical and chemical barrier to oligodendrocyte migration and axon engagement.
What role does N-acetylaspartate (NAA) play in the CNS?
NAA is a CNS metabolite involved in myelin lipid synthesis and is a marker of neuronal health and activity.
How do oligodendrocytes acquire the energy required for myelination?
Oligodendrocytes primarily use lactate and glucose, obtained via astrocyte-neuron metabolic coupling, as energy sources.
What is remyelination, and what factors are known to enhance this process?
Remyelination is the repair of damaged myelin, and it can be promoted by factors like growth factors, neural activity, and pharmacological agents targeting myelin-inhibitory pathways.
Name one approach being studied for potential therapeutic remyelination in diseases like multiple sclerosis.
Stem cell therapy and growth factor delivery are under investigation for enhancing remyelination in demyelinating diseases like MS.
How does oligodendrocyte death impact neurons in white matter tracts?
Oligodendrocyte loss leads to axonal degeneration due to the loss of metabolic support and myelin insulation necessary for axon survival.
IN CLASS MINI-QUIZ QUESTION 1:
How can you stimulate oligodendroglial plasticity (how can you stimulate adult myelin plasticity)?
Using your brain, keeping it active (use it or lose it) to avoid degeneration of cells and such. Also keeping generally healthy and active but mostly cognitive stimulation.
IN CLASS MINI-QUIZ QUESTION 2:
What is the evolutionary cost of myelination?
Myelin degenerative diseases, you can’t have myelin degeneration without myelin. It also takes up some brain energy but that’s not necessarily a bad thing.
