Histo of CNS

Question 1

Typical neuron cell body

Answer 1

1. large nucleus w a well developed nucleolus & nissl substance
2. numerous dendrites and long axon emerges from axon hillock

Question 2

Neuropil is:

Answer 2

dense network of nerve fibers & their branches & synapses, together with glial filaments

Question 3

Anterograde transport

Answer 3

carries material from the nerve cell body to axon. Kinesin-MT motor protein

Question 4

Retrograde transport

Answer 4

carries material from axon terminal to cell body or dendrites. utilizes dynein

Question 5

Slow axonal transport

Answer 5

speed 0.2-4 mm/day. Anterograde movement typically cytoskeletal elements

Question 6

Fast axonal transport

Answer 6

20-400 mm/day, bidirectional movement of organelles. retrograde may include endocytosed toxins and viruses

Question 7

Synaptic communication is uni or bidirectional?

Answer 7

unidirectional

Question 8

In a chemical synapse presynaptic terminal bouton contains what?

Answer 8

lots of mitochondria and synaptic vesicles with NT released by exocytosis

Question 9

separating the pre and postsynaptic membrane is

Answer 9

synaptic cleft 20-30 nm wide

Question 10

Postsynaptic cell membrane includes what?

Answer 10

receptors for NT and Ion channels to initiate new impulse

Question 11

Astrocytes form

Answer 11

a vast network of delicate terminals contacting synapses and other structures. Terminal processes of a single astrocyte associate with 1M synaptic sites

Question 12

Proximal regions of astrocytes are reinforced with what intermediate filament?

Answer 12

glial fibrillary acid protein (GFAP)

Question 13

Oligodendrocytes

Answer 13

Extend processes that enwrap nearby axons in myelin, will enrap axons from multiple neurons and a single axon can be wrapped by multiple oligo’s

Question 14

Oligodendrocytes on a histo slide

Answer 14

usually appear as small cells with rounded condensed nuclei and unstained cytoplasm.

Question 15

Ependymal cells

Answer 15

columnar or cuboidal cells that line the brain ventricles and central canal of SC

Question 16

Apical end of ependymal cells

Answer 16

may have cilia and long microvilli, facilitate movement of CSF, involved in absorption

Question 17

Ependymal cells are joined…

Answer 17

apically by apical junctional complexes. no basal lamina present.

Question 18

Choroid plexus is found where

Answer 18

roofs of 3rd and 4th ventricles and parts of lateral ventricle walls.

Question 19

Choroid plexus is composed of…

Answer 19

thin, elaborated folded layer of well-vascularized pia mater covered by cuboidal ependymal cells.

Question 20

Action of choroid plexus is to

Answer 20

remove H2O from blood and release it as CSF.

Question 21

Microglia

Answer 21

major mechanism of immune defense in the CNS, originate from monocytes

Question 22

Astrocyte function (5)

Answer 22

1. BBB barrier
2. Regulates interstitial fluid comp
3. structural and organization to CNS
4. Assists neuronal development
5. Replicates to occupy space of dying neurons

Question 23

Oligodendrocyte function

Answer 23

1. myelinates and insulates CNS axons

2. Allows faster action potential

Question 24

Ependymal cell function:

Answer 24

1. lines ventricles of brain and central canal of SC

2. assist in production and circulation of CSF

Question 25

Function of microglial cells

Answer 25

1. phagocytic cells that move through CNS

2. Protects CNS by engulfing infectious agents and other potential harmful substances

Question 26

Molecular layer of cerebellum:

Answer 26

has much neuropil and scattered neuronal cell bodies

Question 27

Purkinje cells layer of cerebellum

Answer 27

extend dendrites t/o molecular layer as a branching basket of nerve fibers-conspicuous in HE stain sections.

Question 28

Granular layer cerebellum

Answer 28

contains various very small densely packed neurons and little neuropil

Question 29

The cerebral cortex is divided into old and new called

Answer 29

Archicortex-3 layers
neocortex- 6 layers
90% of cortex is neocortex

Question 30

Neocortex has cells divided into 5 categories

Answer 30

1. pyramidal
2. granule (stellate)
3. Cells of martinotti
4. Fusiform
5. horizontal cells of cajal
   * all cortex contains supporting glia as well

Question 31

Pyramidal cells

Answer 31

pyramid shaped cells with apex directed towards cortical surface. Huge UMN of the motor cortex (betz) are the largest of these cells

Question 32

Granule (Stellate) cells

Answer 32

small neurons with a cell body in the shape of a star

Question 33

Cells of martinotti

Answer 33

small polygonal cells with a few short dendrites

Question 34

Fusiform cells

Answer 34

spindle shaped cells oriented at right angles to the surface of cerebral cortex

Question 35

Horizontal cells of Cajal

Answer 35

small and spindle shaped but oriented parallel to the surface (least common)

Question 36

6 cortical layers

Answer 36

1. Molecular
2. External granular
3. External Pyramidal
4. Inner Granular
5. ganglionic (internal pyramidal)
6. Multiform (polymorphic)

Question 37

Molecular cortical layer:

Answer 37

consists largely of fibers, most of which travel parallel to surface & mostly neuroglial cells and horizontal cells of cajal

Question 38

External granular cortical layer:

Answer 38

consists mainly of small pyramidal cells and granule cells

Question 39

External pyramidal cortical layer:

Answer 39

pyramidal cells are larger and pyramid shape, not sharply demarcated from layer 2

Question 40

Inner granular cortical layer:

Answer 40

many small granule cells

Question 41

Ganglionic cortical layer:

Answer 41

very large pyramidal cells (betz) motor areas

Question 42

Multiform (polymorphic) cortical layer:

Answer 42

cells of diverse shape, many are fusiform cells

Question 43

Alzheimer’s

Answer 43

memory failure progressing to motor skills, speech, sensation-most common

thinning of gyri esp in frontal and temporal lobes

Question 44

Alzheimer’s histo

Answer 44

amyloid b plaques: amorphous, pink masses in cortex

neurofibrillary tangles- flame shaped skeins formed by abnormal accumulation of tau