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Flashcards in Central Nervous system Deck (10)
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1

Differentiate between grey matter and white matter

1. grey matter: neuron cell bodies located here, glial cells, axons, and dendrites. fiber rich regions between cell bodies are called neuropil
2. white matter: long distance myelinated axon tracts. Astrocytes and oligodendrocytes are also present

2

Describe the characteristics of synapses and spines.

-pre-synaptic component, characterized by presence of synaptic vesicles, the active zone: site of synaptic vesicle fusion and neurotransmitter release
-post-synaptic component: found of dendrites, cell bodies, or axons
-spines: small protrusions from dendritic staff where majority of excitatory glutamatergic synapses are found

3

What are the characteristics of astrocytes?

-stellate cells that express glial fibrillary acidic protein (GFAP) and numerous processes. vimentin and intermediate filaments.
-function: maintain extracellular environment of CNS, regulate concentration of ions, clear excess glutamate, enhance neuronal ability to combat oxidative stress.
-have endfeet: forms glia limitans at brain surface and around blood vessels
-reactive gliosis: hypertrophy of cell body, increased growth of processes, increase in GFAP expression and proliferation-->limit neuronal injury or form glial scar to limit axonal regeneration

4

What are the characteristics of oligodendrocytes?

-myelin formation in CNS
-can myelin ate multiple axons
-late event in CNS development

5

What are the characteristics of microglia cells?

-resident macrophages of the brain, identify and phagocytose infectious agents that gain access to the CNS
-motile, can sample and remodel local environment
-possible participation in synaptic pruning
-removal of dying cells and debris

6

Describe the basis of the blood brain barrier

-formed by endothelial cells of capillaries-prevents large or hydrophilic molecules from penetrating brain parenchyma
-tight junctions, limited vesicular transport, high mitochondria number

7

what are the circumventricular organs?

-circumventricular organs: interrupted BBB
1. median eminence and neurohypophysis-invovled in regulation of pituitary hormones
2. area postrema-in medulla-chemoreceptor trigger zone for vomiting-detect blood borne substances

8

Describe the characteristics of ependymal cells and the choroid plexus

-ependymal cells: ciliated simple cuboidal epithelium lining ventricles and central canal of spinal cord
-cilia assist in circulation of CSF through ventricles
-Choroid plexus made of ependymal cells- they have tight junctions and forms blood-CSF barrier
-active transport of Na+ -produces most of CSF

9

What is the difference between CT and MRI?

CT=computed tomography
-uses ionizing radiation and forms cross sectional images. useful in evaluation of trauma, stroke, in emergency setting. but has poor CNS tissue contrast
MRI=magnetic resonance imaging
-detects RF signal from H nuclei in magnetic field
-optimal imaging of CNS
-many sequences possible

10

What is the difference in T1WI and T2WI in MRI?

Water/CSF is dark in T1 and bright in T2
-brain lesions: dark in T1 and bright in T2
-vascular malformations: dark on T1 and T2
-Neoplasms: bright on post contrast T1 due to leakage of contrast due to breakdown of BBB

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