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Flashcards in Histology of the CNS Deck (26)
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1
Q

what are the supporting cells of the CNS

A

astrocytes, oligodendrocytes, microglia, ependymal cells

2
Q

3 major components of a neuron

A

soma (cell body), dendrties, and an axon

3
Q

where are nissl bodies found and first part where they are not found

A

found in the soma

-first not seen in the axon hillock

4
Q

what is a bipolar neuron and where is it found

A

cell body with single axon emerging from either side of it

  • found in sensory strucutres
  • retina, olfactory, epithelium, vestibular and auditory systems
5
Q

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
A

pseudounipolar neuron

6
Q

multipolar neurons and types

A

many dendrites and a single long axon emerge from cell body

  • pyramidal cell of cerebral cortex
  • purkinje cell of cerebellar cortex
7
Q

cerebral cortex layers external to internal

A
molecular layer
external granular layer
external pyramidal cell layer
internal granular layer
internal pyramidal cell layer
multiform cell layer
white matter
8
Q

cerebellar organization

A

molecular layer
purkinje cell layer
granular layer
white matter

9
Q

4 types of synapses

A

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

10
Q

what is a dendritic spine

A

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
11
Q

what do astrocyte end feet cover

A

dendrites and cell bodies

  • inner surface of pia matter
  • every blood vessel of the CNS (perivascular feet of astrocytes)
12
Q

what are joined end feet processes of astrocytes coating the pia mater called

A

glia limitans

13
Q

3 main components of the blood-brain barrier

A

1) tight junctions from the endothelial cells
2) basal lamina of the endothelial capillaries
3) perivascular astrocyte end-feet

14
Q

1 oligodendrocyte myelinates ___ axons

A

multiple

15
Q

in CNS the the astrocyte end feet have ___ contact with axon

-they do/don’t interdigitate

A

direct, do not interdigitate

-space is occupied by astrocytic end foot process

16
Q

microglial cell function

  • produce what
  • enter from where?
A

macrophages of CNS

  • produce chemoattractants capable of recruiting leukocytes across BBB to initate neruoimmunologic diseases
  • enter from the blood
17
Q

2 types of ependyma cells

A

1) tanycyte

2) ependymal cells

18
Q

features of tanycyte cells

A
  • 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
19
Q

features of ependymal cells

A
  • cilia and microvilli on apical domian (not on tanycyte), abundant mitochondria,
  • basal domain in contact with astrocytic processes
  • attached to each other by desmosomes
20
Q

in the brainstem the central canal is lined primarily by which kind of ependyma

A

ependymal cells

21
Q

what is the choroid plexus

A

ependyma wraped around fenestrated blood vessels

22
Q

arachnoid-CSF barrier

A

in brain need arachnoid matter right up against dura matter to prevent subdural fluid from building up such as a hematoma

23
Q

blood-CSF barrier

A

cells that line the choroid plexus prevent mixing of blood and CSF
-choirodal epithelial cells

24
Q

pia matter:

A

single layer of flat cells on the brain surface

25
Q

arachnoid villi function

-blocking it

A

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
26
Q

dura matter

A

tough and collagenous

-surround brain and spinal cord