Histology and Cells of CNS

Question 1

name the three functional classes of neurons

Answer 1

sensory
motor
interneuron

Question 2

what is the rough ER called in neurons?

Answer 2

Nisl Substance

Question 3

where is there not much rough ER?

Answer 3

near the axon hillock…will appear lighter on slide

Question 4

name the five neuroglia cells

Answer 4

astrocytes
schwann cells
ependymal cells
oligodendrocytes
microglia

Question 5

what cell contributes to the BBB?

Answer 5

astrocyte foot processes

Question 6

what are the 5 functions of astrocytes

Answer 6

scavenge debris
supply energy for metabolism
contribute to the glie limitans
structural support
help form scar tissue

Question 7

what cell covers the nodes of ranvier in the CNS?

Answer 7

astrocytes

Question 8

what is the glia limitans?

Answer 8

barrier between pia mater and nervous tissue

Question 9

what is the role of the oligodendrocytes in the CNS?

Answer 9

make myelin for several neurons each

Question 10

what is the role of the microglia?

Answer 10

small phagocytic cells derived from monocytes, can become APCs when activated and secrete cytokines

Question 11

what is the function of schwann cells?

Answer 11

in PNS they wrap neurons with myelin…can only do one per schwann cell though`

Question 12

can a schwann cell support PNS neurons even if it isnt wrapping with myelin?

Answer 12

yes…but just isnt wrapped in myelin but surrounds many cells

Question 13

what is the role of the ependymal cells?

Answer 13

secrete CSF in the ventricles and line the ventricles of the brain

Question 14

what neurons are usually unmyelinated?

Answer 14

postganglionic neurons in the ANS

Question 15

name the three layers surrounding a nerve

Answer 15

epineurium
perineurium
endoneurium

Question 16

what does the epineurium cover?

Answer 16

the whole nerve

Question 17

what does the perineurium cover?

Answer 17

bundle of nerve fibers within the nerve

Question 18

what is a ganglia?

Answer 18

encapsulate aggregation of neuronal cell bodies outside of the CNS

Question 19

what are the two types of ganglia?

Answer 19

autonomic and sensory

Question 20

what surrounds cells in the autonomic ganglia?

Answer 20

satellite cells

Question 21

are cell bodies in autonomic ganglia normal or irregular shape?

Answer 21

irregular shape

Question 22

are cell bodies in sensory ganglia normal or irregular shape?

Answer 22

normal round shape

Question 23

are cells in autonomic close together or spread out?

Answer 23

spread out

Question 24

are cells in sensory ganglia close together or spread out?

Answer 24

close

Question 25

what type of neuron is in sensory ganglia?

Answer 25

pseudounipolar

Question 26

name the six layers of the cerebral cortex from out to in

Answer 26

``` molecular external granular external pyramidal internal granular internal pyramidal multiform layer ```

Question 27

what type of cell is in the pyramidal layers?

Answer 27

pyramidal shaped cell bodied neurons

Question 28

name the three parts of the BBB

Answer 28

endothelial cells foot processes from astrocytes and thick basement membrane

Question 29

do oligodendrocytes or schwann cells have a basal lamina?

Answer 29

schwann cells

Question 30

what is the role of satellite cells?

Answer 30

provide support and modulate neuronal enviro in the PNS

Question 31

what are the two directions for axonal movement?

Answer 31

anterograde and retrograde

Question 32

anterograde movement on axon happens at what two speeds?

Answer 32

slow...1mm/day and fast...400mm.day

Question 33

retrograde movement happens at what speed?

Answer 33

intermediate...100-200mm/day

Question 34

retrograde transport moves in what direction?

Answer 34

from axon terminal to cell body

Question 35

anterograde trsnport moves in what direction?

Answer 35

cell body to axon terminal

Question 36

dynein assists in retrograde or anterograde?

Answer 36

retrograde

Question 37

kinesis assists in retrograde or anterograde?

Answer 37

anterograde

Question 38

what is axotomy?

Answer 38

cut an axon

Question 39

what happens to the axon of neuron after axotomy?

Answer 39

anterograde degen and retrograde degen right at cut

Question 40

what happens to cell body of neuron after axotomy? 3 things

Answer 40

nucleus moves to periphery nissl substance decreases in amount cell swells

Question 41

explain why crush injuries lead to accurate nerve reinnervation

Answer 41

axons distal to site of crush still have basal lamina tract that was layed down by the schwann cells

Question 42

what happens to axon growth following crush injury?

Answer 42

proximal stump grows into distal stump and follows basal lamina tract

Question 43

explain why transection of a nerve leads to less accurate reinnervation

Answer 43

basal lamina put down by the schwann cells gets cut too and so the proximal stumps can go into different distal stumps and innervate in a different spot than they are supposed to

Question 44

what is it called when you have reinnervation following a nerve transection but it is a bit off?

Answer 44

anomalous reinnervation

Question 45

what happens when regeneration of axon occurs but it cannot find the distal stump basal lamina?

Answer 45

leads to axonal cluster...called a neuroma...and there is no reinnervation so degenerates

Question 46

can remyelination occur in CNS or PNS or both?

Answer 46

really just schwann cells in PNS able to do it

Question 47

can regeneration occur in the CNS?

Answer 47

not as likely as in PNS because there is not a basal lamina like put down by the schwann cells in the PNS

Question 48

what is molecular plasticity?

Answer 48

axon membranes acquire new voltage Na channels after injury

Question 49

what is synaptic plasticity?

Answer 49

increased activity at synapse

Question 50

what is collateral sprouting of axons?

Answer 50

targets that lose innervation can get sprouts of axons from surrounding axons