Chapter 2: Histology of the Nervous System Flashcards
Neurofilaments
provide structural support for the neuron, and are most numerous in the axon and the proximal parts of dendrites
Microfilaments
- form a matrix near the periphery of the neuron.
- prominent in growth cones of neuronal processes and functions to aid in motility of growth cone
- also prominent in dendrites and forms structural specializations at synaptic membranes
Where are microtubules found in the neuron?
all parts of the neuron, and are the cytoplasmic organelles used in axonal transport
What are Lewy bodies?
cytoplasmic inclusions of degenerating neurons of the substantia nigra, pars compacta, evident in Parkinson’s disease and in cortical and brain-stem neurons seen in certain forms of dementia
What are Negri bodies?
eosinophilic cytoplasmic inclusions seen in degenerating neurons in the hippocampus and cerebellar cortex in patients with rabies
Tau proteins becominng excessively phosphorylated prevents what action of the neuron?
prevents crosslinking of microtubules
Neurofibrillary tangles are prominent features of what conditions?
Alzheimer’s disease, amyotrophic lateral sclerosis, and Down syndrome
What are neurofibrillary tangles?
when tau proteins become excessively phosphorylated and prevent crosslinking of microtubules
What motor protein is important for fast anterograde transport in the neuron?
kinesin
Is slow anterograde transport dependent on microtubules or ATPase motor molecules?
neither
How does a person with diabetes manage to get polyneuropathies producing characteristic “glove and stocking” pattern?
hyperglycemia results in an alteration of proteins that form microtubules, which may disrupt axonal transport
Is retrograde transport faster or slower than anterograde transport?
slower than anterograde transport
What are the most numerous glial cells in the CNS?
astrocytes
Which glial cells have large numbers of radiating processes?
astrocytes
GFAP?
glial fibrillary acidic protein (GFAP). Large bundles of intermediate filaments that are contained within astrocytes
What are some viruses that are taken up into the neuron with retrograde axonal transport?
polio, herpes, and rabies viruses and tetanus toxins
What are radial glia?
precursors of astrocytes that guide neuroblast migration during CNS development
What are microglia cells?
smallest glial cells in the CNS
Are microglia cells derived from ecotoderm? Explain.
No, they are derived from bone marrow monocytes and enter the CNS after birth
What are oligodendrocytes?
form myelin for axons in the CNS
What are Schwann cells?
supporting cells of the peripheral nervous system