Flashcards in W19-L2: Cells of the CNS Deck (28):
How many layers of neurones are there in the cortex?
What is the cortex?
Thin 1 cm layer of cell bodies that is the outermost layer of the brain
What stains can you use for neurones
H & E and Silver stain (golgi stain)
What are ependymal cells?
Low columnar or cuboidal cells that line the central canal of the spinal cord and the ventricle within the brain.
How is CSF flow aided?
cilia on apical surface of ependymal cells
What is the difference between ependymal cells and epithelial cells?
ependymal cells have non basal laminar
How are neurones different from other cells?
-Neurons are specialized for signalling (Morphologically distinct, Electrically active, Rapid communication, Long distance)
-High level of protein synthesis
Regulation of neuronal morphology
Via the cytoskeleton
Actin's role in neuronal cytoskeleton
Dynamic assembly/disassembly allows shape changes and movement (e.g spines and growth cones)
Intermediate filament's role in neuronal cytoskeleton
-In all processes
Microtubule's role in neuronal cytoskeleton
-Composed of tubulin
How are high levels of protein production seen?
large pale nucleus, Nissl bodies (rough ER, free ribosomes)
Most important function of astrocytes
Neurotransmitter uptake and degradation especially glutamate and GABA
Other passive support functions of astrocytes
-K+ homeostasis (remove excess K+)
-neuronal energy supply
-maintenance of BBB
-injury response and recovery
Active functions of astrocytes
-Modulation of neuronal function (via Ca2+)
-Modulation of blood flow
What is caused by inhibition of glial glutamate transporters?
cells are more depolarized, extended depolarisation can cause cell death
How are glia excited?
Causes of glial excitement
as ATP, glutamate
Mechanism of glia commuication
Glial cells contain synaptic vesicles and show exocytosis.
regulation of neuronal function by astrocytes
-Neurons are inhibited by calcium wave (hyperpolarised)
-Mechanism involves release of ATP from glia which causes Ca2+
How do Astrocytes regulate vascular tone?
Calcium wave initiated within an astrocyte causes vasoconstriction or vasodilation.
Difference between oligodendrocytes and schwann cells
Schwann is in the PNS, Oligodendrocyte is CNS and schwann only does one axon compared to many
-local defence cells from bone marrow
-5-20% of cells in mouse brain
-Resemble macrophages – phagocytic
Role of microglia
-Constantly survey the CNS. (function in normal healthy tissue)
-Change rapidly in response to inflammation or
injury- upregulate cytokines/growth factors
Structure of peripheral nerves
-One or more bundles (fascicles) or nerve fibres with epineurium, endoneurium and perineurium
collagenous tissue that surrounds fascicles of nerve fibres
If there is more than one fascicle, than there is further layer of collagenous tissue