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Flashcards in Histology of the CNS Deck (26):

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



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

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


arachnoid villi function
-blocking it

get blood from the brain back out
-send to venous sinus which returns blod to the heart
-take CSF into arachnoid villus then excess goes into venous sinus
-if block then subarachnoid space fills up with fluid and pushes on brain = hydrocephalus


dura matter

tough and collagenous
-surround brain and spinal cord