A 8 Histology of CNS Flashcards
Histo appearance of GABA neuron?
GABA is packaged in elongated (flattened), small clear vesicles.
Histo appearance of Glutamate neurons?
Glutamate is packaged in small, clear, spherical vesicles. At glutamatergic synapses, postsynaptic membrane is electron dense.
Histo appearance of catecholamine neurons?
Catecholamines and 5HT are packaged in large, spherical, dense core vesicles.
How fast are slow & fast anterograde transport and what do they carry?
Slow: 1 mm/day, proteins and microfilaments
Fast: 100mm/day, organelles and vesicular substance
(Retrograde is always fast)
Bipolar neurons are found in what structures?
3 sensory structures: Ear, Eye, Nose. “EEN!”
“Slow” acting neurotransmitters, a.k.a. modulators are?
Categories: Neuropeptides & Steroids
Examples: Catecholamines, Serotonin, Acetylcholine
Fast acting neurotransmitters are?
Glutamate, GABA
Cocaine inhibits what?
Dopamine transporter, which clears dopamine from the synaptic cleft
Multiple Sclerosis is a disease of what?
Myelin in the CNS is attacked & degraded.
Oligodendrocytes can myelinate how many axons?
many, up to 50
Fibrous astrocytes have what characteristics?
-Found in white matter
-Few & long
“Few are white” mneumonic
Astrocytes do what?
- control composition of extracellular fluid
- release glutamate, increasing excitation of local neurons
- Form foot processes around blood vessels, but do NOT contribute to tight junctions.
Protoplasmic astrocytes have what characteristics?
- Many Short & branched
- Found in gray matter
Ependymal cells do what?
- Form leaky brain-to-CSF barrier in brain and spinal cord
- Ciliated simple columnar cells move the CSF
Microglia do what?
- Phagocytose
- Release proteases & free radicals
Choroid Plexus is what?
- Simple cuboidal cell villi covering capillaries
- Its epithelial cells form tight blood-to-CSF barrier. These touch the ependymal epithelial cells (which don’t contribute to the barrier)
Nerve fiber= ?
-Axon plus covering. (myelination)
T/F Unmyelinated axons are surrounded by Schwann cells?
True
In what order are cortex layers laid?
6-5-4-3-2-1-White
3 layers of cerebellum are?
Out->In:
Molecular
Purkinje
Granular
Endoneurium is secreted by what, and made up of which type of collagen?
- Schwann cells
- Type 3
- Some fibroblasts
- surround a nerve fiber
Perineurium consists mostly of what?
-Flattened fibroblasts surrounding fassicles (clusters of nerve fibers)
Compared to autonomic ganglion, a sensory ganglion has what appearance?
- satellite cells tightly packed around neurons
- neuronal cell bodies are clustered
- nucleoli tend to be in the center of the cell body.
- (Also note there is no synapse here)
Epineurium consists of what?
-Dense connective tissue w/ Type 1 collagen and fibroblasts surrounding entire nerve
A column is what?
- Functionally related axons
- Perpendicular to cortex
what is the most common type of neuron?
multipolar
A layer, lamina, strata is what?
- Functionally related cells
- Parallel to cortex
Funiculus is what?
-Several parallel tracts in the CNS (the tracts would be functionally related to themselves but maybe not to each other)
Fasciculus/fascicle -> funiculus, commissure, peduncle, lemniscus are what?
- Anatomic grouping of cell axons (maybe not functionally related)
- Lemniscus indicates crescent shape
- Peduncle indicates short & stubby shape
- In the CNS, a group of Fascicles make a Funiculus
Tract is what?
- USUALLY functionally related axons (that would then form into groups called fascilulus/lemniscus/commissure
- Usually named by its origin and insertion
what is nissl substance?
rough ER in a nerve cell
what is a neurofilament?
an intermediate filament of a nerve cell. Note: these are argyrophilic
what is lipofuscin?
garbage material left in a cell and stored in a lysosome. Every cell accumulates this but since nerve cells live so long, they accumulate a lot of it.
what is the axolemma?
the plasma membrane covering the axon.
what are two other names for a cell body?
perikaryon and soma
which are the biogenic amine neurotransmitters?
catacholamines (epi, norepi, dopamine) as well as serotonin.
the neurotransmitter glutamate is excitatory/inhibitory?
excitatory
If a neuron makes the GABA neurotransmitter, what type of neuron is it?
Gabaergic. The neuron is named for the neurotransmitter that it releases.
What is the function of a neuromodulator?
to modify the sensitivity of neurons to neurotransmitters.
what are the two glial cells in the PNS called?
satellite cells
Schwann cells
How many neurons can a schwann cell myelinate?
only one neuron! it can wrap up many neurons but only myelinate one.
what are the two layers of the Dura matter called?
periosteal and menigeal layer of the Dura matter
what makes up the blood brain barrier?
Endothelial cells with very tight junctions.
How do local anesthetics work on the nerve?
they block the Na+ channels necessary for impulse transmission.
Does regeneration of a nerve occur in the body?
Yes but only minimally in the PNS. The portion of the nerve distal to the lesion dies and the schwann cells help direct/regrow the distal portion again.
In the CNS, a group of fasciculi are called what?
funiculus
which type of glial cell is derived from bone marrow?
microglia
