Histology of the CNS Flashcards
what are the supporting cells of the CNS
astrocytes, oligodendrocytes, microglia, ependymal cells
3 major components of a neuron
soma (cell body), dendrties, and an axon
where are nissl bodies found and first part where they are not found
found in the soma
-first not seen in the axon hillock
what is a bipolar neuron and where is it found
cell body with single axon emerging from either side of it
- found in sensory strucutres
- retina, olfactory, epithelium, vestibular and auditory systems
single axon that divides short distance from the cell body
- found in the snesory ganglia of cranial and spinal nerves
- cell body sits in the spinal cord
pseudounipolar neuron
multipolar neurons and types
many dendrites and a single long axon emerge from cell body
- pyramidal cell of cerebral cortex
- purkinje cell of cerebellar cortex
cerebral cortex layers external to internal
molecular layer external granular layer external pyramidal cell layer internal granular layer internal pyramidal cell layer multiform cell layer white matter
cerebellar organization
molecular layer
purkinje cell layer
granular layer
white matter
4 types of synapses
1) axosomatic: axon termianl ending on soma
2) axoaxonic: axon terminal contacting other axon term
3) axodendritic: axon ending on dendrite
4) axospinous: axon terminal facing dendritic spine
what is a dendritic spine
consists of an expanded head connected to dendrite shaft by neck
- normal shaft contains microtubules
- spine has actin filaments with postsynaptic density
- NT receptors and ion channels are localized in postsynaptic density
what do astrocyte end feet cover
dendrites and cell bodies
- inner surface of pia matter
- every blood vessel of the CNS (perivascular feet of astrocytes)
what are joined end feet processes of astrocytes coating the pia mater called
glia limitans
3 main components of the blood-brain barrier
1) tight junctions from the endothelial cells
2) basal lamina of the endothelial capillaries
3) perivascular astrocyte end-feet
1 oligodendrocyte myelinates ___ axons
multiple
in CNS the the astrocyte end feet have ___ contact with axon
-they do/don’t interdigitate
direct, do not interdigitate
-space is occupied by astrocytic end foot process
microglial cell function
- produce what
- enter from where?
macrophages of CNS
- produce chemoattractants capable of recruiting leukocytes across BBB to initate neruoimmunologic diseases
- enter from the blood
2 types of ependyma cells
1) tanycyte
2) ependymal cells
features of tanycyte cells
- basal processes extend through astrocytic process to form end feet on BV so it can receive blood and make CSF
- attached to each other by tight junctions
features of ependymal cells
- cilia and microvilli on apical domian (not on tanycyte), abundant mitochondria,
- basal domain in contact with astrocytic processes
- attached to each other by desmosomes
in the brainstem the central canal is lined primarily by which kind of ependyma
ependymal cells
what is the choroid plexus
ependyma wraped around fenestrated blood vessels
arachnoid-CSF barrier
in brain need arachnoid matter right up against dura matter to prevent subdural fluid from building up such as a hematoma
blood-CSF barrier
cells that line the choroid plexus prevent mixing of blood and CSF
-choirodal epithelial cells
pia matter:
single layer of flat cells on the brain surface
