Neurohistology and Nervous System repair

Question 1

Where is the subarachnoid space

Answer 1

between the pia and the arachnoid mater

Question 2

what is a perikaryon

Answer 2

neuron cell body

Question 3

what is a multipolar neuron

Answer 3

cell body at one end

Question 4

what is bipolar neuron

Answer 4

cell body in the middle

Question 5

what is a pseudopolar neuron

Answer 5

cell body in the middle, on a stalk

Question 6

what is found in grey matter

Answer 6

cell bodies

Question 7

what is found in white matter

Answer 7

axons

Question 8

what is the axon hillock

Answer 8

where the cell body meets the axon

Question 9

what does nissl substance stain

Answer 9

ER and polyribosomes

Question 10

what is the neocortex

Answer 10

cerebral cortex

Question 11

how many layers of the cerebral cortex are there

Answer 11

6

Question 12

how many layers of the cerebellar cortex are there

Answer 12

3

grey superficially and white is deep

Question 13

what are the layers of the cerebellar cortex

Answer 13

molecular
purkinje cells
granular

Question 14

what is found in the granular layer

Answer 14

granular cells and golgi cells

Question 15

what is found in the molecular layer

Answer 15

basket cells, stellate cells and fibres

Question 16

describe purkinje cells

Answer 16

multipolar neurons
largest cells in the cerebellum
pear shaped
dendritic tree which expands outwards into the molecular layer

receive afferent information from the CNS

Question 17

Where are astrocytes, oligodendroglia, ependymal cells and microglia found

Answer 17

the CNS

Question 18

where are schwaan cells and satelite cells found

Answer 18

PNS

Question 19

what do oligodendroglia and schwaan cells do

Answer 19

form myelin sheaths

Question 20

what do astrocytes do

Answer 20

structural and metabolic support for neurons

Question 21

where are fibrous astrocytes found

Answer 21

white matter of the CNS

Question 22

Where are protoplasmic astrocytes found

Answer 22

grey matter of the CNS

Question 23

where are muller glia found (astrocytes)

Answer 23

retina

Question 24

where are radial glia (astrocytes) found

Answer 24

developing CNS

Question 25

What forms the BBB

Answer 25

endothelial cells, tight junctions and astrocyte end feet

Question 26

what is the maximum weight allowed through the BBB

Answer 26

500 daltons

Question 27

what is the function of ciliated cuboidal ependymal cells

Answer 27

line the ventricle, secrete and reabsorb CSF

Question 28

where is CSF produced

Answer 28

chroroid plexus

Question 29

what is the function of microglia

Answer 29

immune function like macrophages, able to phagocytose cell debris upon injury release cytokines

Question 30

what are the functions of oligodendrocytes

Answer 30

one cell is able to myelinate several axons

Question 31

what cells is affected in MS and leukodystrophy

Answer 31

oligodendrocytes

Question 32

how many schwaan cells can myelinate one axon

Answer 32

1 cell per axon

Question 33

what is the function of myelin

Answer 33

Insulation and increased velocity via saltatory conduction

Question 34

what axons are unmyelinated

Answer 34

fibres carrying pain, temperature and itch

Question 35

describe unmyelinated axons in the PNS

Answer 35

enveloped by schwaan cells this does not happen in the CNS

Question 36

what are ganglia

Answer 36

aggregations of nerve cells outside the CNS

Question 37

what are ganglion cells surrounded by

Answer 37

flattened satellite cells (fibroblasts)

Question 38

what is the perineurium

Answer 38

surrounds several axons in order to create a fascicle

Question 39

what is the epineurium

Answer 39

surrounds several fascicles

Question 40

what is the endonerium

Answer 40

surrounds individual nerve fibres

Question 41

what is found in the lateral part of the spinal cord grey matter

Answer 41

autonomic motor neurons

Question 42

what is found in the anterior part of the grey matter in the spinal cord

Answer 42

somatic motor neurons

Question 43

what is found in the posterior horns of the grey matter in the spinal cord

Answer 43

interneurons (reflexes)

Question 44

what is found in white matter in the spinal cord

Answer 44

ascending and descending tracts mostly paired and decussate

Question 45

what is found in anterior white matter columns

Answer 45

motor

Question 46

what is found in lateral white matter columns

Answer 46

motor or sensory

Question 47

what is found in dorsal white matter columns

Answer 47

sensory

Question 48

where is the median fissure

Answer 48

anterior

Question 49

where is the median sulcus

Answer 49

posterior

Question 50

what is the histological appearance of motor neurons in the spinal cord

Answer 50

``` multipolar cell bodies are large and found in the ventral horn large pale staining nucleus prominent nucleolus nissl bodies ```

Question 51

can peripheral nerves be repaired

Answer 51

yes CNS axons cannot

Question 52

what is Wallerian degeneration

Answer 52

after trauma the PNS and CNS repairs by clearing debris and lays the foundation for regrowing nerve fibres does not work properly in the CNS, also inhibitory factors in the environment contributing to failed repair

Question 53

describe the process of Wallerian degeneration in the PNS

Answer 53

injury causes fragmentation of the axon and myelin sheath schwaan cells become reactive and proliferate macrophages phagocytose debris schwaan cells express growth factor and form bands of Bungner nerve fibres grow towards the bands nerve fibres reconnect with end organs and are remyelinated by schwaan cells

Question 54

Why does Wallerian degeneration fail in the CNS

Answer 54

inflammation myelin debris is not completely removed glial scar is formed by reactive astrocytes astrocytes regrowth of axons is inhibited by myelin debris and glial scar a cystic cavity forms lack of growth promoting molecules and an inhibitory environment may have reactive end bulbs oligodendrocytes > myelin debris astrocytes > glial scar

Question 55

describe reactive astrocytes after injury

Answer 55

hypertrophy | expression of inhibitory molecules and normal molecules which forms a glial scar which the axon cannot pass through

Question 56

where are glial cells segregated into CNS or PNS

Answer 56

glial limiting membrane at the dorsal root entry zone

Question 57

what is the substantia gelatinosa

Answer 57

a mass of gelatinous gray matter that lies on the dorsal surface of the dorsal column and extends the entire length of the spinal cord into the medulla oblongata and transmits painful sensory information.

Question 58

what is the gracile fasculus

Answer 58

carries information from the lower limbs found in the posterior column medial lemniscus pathway