Histology of the CNS Flashcards
neurons
three regions: soma (cell body), dendrites, axons
astrocytes
present in CNS
branching cells w/ cytoplasmic processes ending in expansions called end-feet
end feet cover neurons, inner surface of the pia mater, every blood vessel of the CNS
glia limitans are jointed end feel processes coating the pia mater
oligodendrocytes (oligodendroglia)
form the myelin sheaths around the axons in CNS
myelinates multiple axons
microglia
resident macrophages of CNS
primary cells to respond to injury to the brain
produce: cehmoattractants
interact w/ astrocytes to modulate the initiation and progression of immune responses
CNS autoimmunity and inflammation
enter from blood
ependymal cells
simple cuboidal epithelium
made of ependymal cells and tancytes
stroma (cell body)
contains nissl bodies
axon
no nissl bodies
bipolar neuron
single axon from either side of the cell body
pseudounipolar neuron
single axon divides a short distance from the cell body
peripheral branch carriers info from the periphery
central branch ends in the spinal cord
multipolar neuron
many dendrites and a single long axon emerges from the cell body
pyramidal cell
multipolar neuron
cerebral cortex
purkinje cell
multipolar neuron
cerebellar cortex
cerebral cortex grey matter layers
molecular layer external granular layer external pyramidal cell layer internal granular layer internal pyramidal cell layer multiform cell layer
cerebellar grey matter layers
molecular layer
purkinje cell layer
granular layer
synapse
- electrochemical signal reaches axon terminal
- synaptic vesicles move and bind to docking proteins
- VG Ca channels open allowing Ca into terminal
- release of the NT into synaptic cleft
axosomatic synapse
axon terminal ending on the soma
axoaxonic synapse
axon terminal contacting another axon terminal
axodendrtic synapse
axon ending on dendrite
axospinous synapse
axon terminal facing a dendritic spine
blood brain barrier
tight junctions b/w endothelial cells are the main components
additional components: basal lamina of the endothelial capillaries, perivascular astrocyte end-feet
myelination CNS
cytoplasmic processes of adjacent oligodendrocytes do not interdigitate
the space is occupied by an astrocyte end foot process
myelination PNS
cyptoplasmic processes of the adjacent Schawann cells interdigitate at the node region
epedymal cells
cillia and microvilli and mito (apical)
contact w/ asrocyte (basal)
attached by desmosomes
hold spinal fluid in
tanycytes
basal processes extend through the astorcytic process layer to from end feet on BV
attached to each other and to ependymal cells by tight junctions
make spinal fluid
chorid plexus
location of production of spinal fluid
ependyma wrapped around fenestrated BV
arachnoid - CSF Barrier
arachnoid membrane prevents the CSF into the subarachnoid space from coming in contact c/ the fluid of the extracellular space of the dura
CSF drains around the cerebral hemispheres to the arachnoid villi placed along the venous sinus
NO CSF UP AGAINST DURA MATER
blood - CSF barrier
formation of CSF by choroid plexus requires passage of an untrafiltrate of plasma through the fenestrated endothelium of the capillary and CT
choroidal epithelial cells transform this ultrafiltrate into an excretory product
meninges
dura mater
arachnoid mater
(subarachnoid space)
pia mater
pia mater
single layer of the flat cells on the brain surface
arachnoid granulations and arachnoid villi
reabsorb CSF
dura mater
tough and collagenous
surrounds the brain and spinal cord
arachnoid villi
protrusions of the arachnoid into the lumen of the venous sinus that allows movement of CSF into venous sinus
malfunction leads to hydrocephalus
