Chapter 3.3 Protection of the Central Nervous System Flashcards
About 90% of the cells within the CNS are not neurons, but ____ cells, or _____
About 90% of the cells within the CNS are not neurons, but glial cells, or neuroglia
Unlike neurons, glial cells do not initiate or conduct ______, but they do communicate via _____ signals
Unlike neurons, glial cells do not initiate or conduct nerve impulses, but they do communicate via chemical signals
Glial cells serve as the _______ tissue of the CNS and, as such, help _____ the neurons both physically and metabolically
Glial cells serve as the connective tissue of the CNS and, as such, help support the neurons both physically and metabolically
What are two basic and essential functions of glial cells
- maintain the homeostatic composition of the extracellular environment surrounding the neurons to keep in within the narrow range for normal function
- actively modulate synaptic function - nearly as important for learning and memor as neurons
What are the four major types of glial cells?
- Astrocytes
- Oligodendrocytes
- Microglia
- Ependymal cells
Named for their starlike appearance, ______ are the most abundant glial cells.
Named for their starlike appearance, Astrocytes are the most abundant glial cells.
What are seven functions of astrocytes?
- Hold neurons together in proper spatial relationships (main ConnectiveT of CNS)
- Scaffold to guide neurons to their proper destination during fetal brain development
- Induce the small blood vessels of the brain to undergo the anatomic and functional changes responsible for establishing the blood-brain barrier
- Important in repair of brain injuries
- Play a role in neurotransmitter activity (take up and degrade glutamate and GABA - halting action)
- Take up excess K+ from the brain ECF (help maintain proper brain ECF ion concentration and normal excitability)
- Enhance synapse formation and strengthen synaptic transmission via chemical signalling with neurons
