Chapter 9: Nerve Cells Flashcards
what cells and structures compose the white matter of the CNS?
- axons
- dendrites
- neuroglia
what cells and structures compose the gray matter of the CNS?
- neuron cell bodies
- neuroglia
describe the nucleus of neurons…
prominent nuclei and nucleolus
neurons are abundant in..
nissl substance
neurons have a well developed
Golgi
neurons are NOT
mitotic
neurons are known for the production of
neurotransmitters
how are neurons specialized for electrical transmission?
by myelin sheaths around the axons
what are the 5 types of neuroglia?
- oligodendrocytes
- astrocytes
- ependymal cells
- microglia
- schwann cells
what are the function of oligodendrocytes?
- form myelin sheaths in the CNS
- allows for saltatory conductions of action potentials
function of actrocytes
- controls extracellular movement by removing excess neurotransmitters
astrocytes communicate via
jap junctions
ependymal cells line what part of the brain and spinal cord?
ventricles
describe the histology of ependymal cells
cubodial w/ microvilli
what is the function of ependymal cells?
to produce CSF in the choroid plexus
microglia are ________ cells
phagocytic
microglia are derived from
monocytes
what is the function of Schwann cells
to produce the myelin sheath
forming nodes of Ranvier
Schwann cells are aka
neurolemmocytes
what protein is used as an immunohistochemical marker for gial cells?
GFAP
which cells comprise the BBB?
endothelial cells w/ tight junctions
astrocyte processes
what is the function of the BBB?
neural protection by restricting passage of molecules & pathogens
what are the 3 layers of CT in peripheral nerves?
- epineurium
- perineurium
- endoneurium
the epineurium is the
external layer of dense CT
the perineurium…
surrounds each fascicle
the endoneurium surrounds each
nerve fiber
which of the 3 layer in CT of peripheral nerves contain reticular fibers
endoneurium
the reticular fibers of the endoneurium are made by
Schwann Cells
what are the 3 meningeal layers?
- Dura mater
- Arachnoid
- Pia Mater
dura mater can be described as
dense regular CT
the arachnoid layer can be described as being
spider-like w/ a subarachnoid space filled w/ CSF
the pia mater is the
innermost meningeal layer
the pia mater is contacted by
glial cells
what are the necessary conditions for the successful repair of nerve damage in the PNS?
- soma not destroyed
- proper reconnection of axon the Schwann cells
describe the process of nerve regeneration in the PNS
injury -> distal degradation -> Schwann cell proliferation
Poliomyelitis occurs when
a virus enters the motor neurons in the ventral horn of the spinal cord
the virus in poliomyelitis kills ___________ causing ___________.
- neurons
- paralysis
glioma is resistant to
chemotherapeutic agents
what is the average survival rate of patients w/ glioma
about 3 months
alzheimer’s can be described as a
neurodegenerative disease
what are the 2 characteristic features of Alzheimer’s?
- Amyloid plaques
- NFTs
how are amyloid beta plaques formed?
from the proteolysis of APP
APP: amyloid precursoe protein
how are NFTs formed?
tau protein forming insoluble plaques
the insoluble plaques in NFTs interfere w/
cytoskeletal microtubules
what are the 3 functions of nervous tissue?
- reception
- processing electrical/chemical signals
- transmission of electrical/chemical
what are the 2 divisions of the NS?
- functional
- anatomical
the functional division of the NS composes what 2 subcategories?
- autonomic
- voluntary
the anatomical division of the NS composes what 2 subcategories?
- CNS
- PNS
what types of cells are found in gray matter?
- neuron cell bodies
- neuroglia
what types of ells are found in the white matter?
- axons/dendrites
- neuroglia
neurons are known for their ____________ and propagation of __________.
- irritability
- impulses
what is the characteristic appearance of neurons?
- large soma
- prominent nucleus & nucleolus
why do neurons typically have a large cell body?
to be able to produce adequate neurotransmitters
neurotransmitters are…
small peptides
what are the 2 cell processes in neurons?
- axons
- dendrites
axons are used to
conduct signals
axons can be very
long
why are there a lot of dendrites?
to increase surface area
what is the function of dendrites?
to receive signals
there is an abundance of what organelle in neurons?
RER
- basophilic
what organelle is “well-developed” in neurons?
Golgi apparatus
neurons are…
NON-MITOTIC
what protein is typically visible in aged neurons?
lipofuchsin
describe lipofushin
- brownish pigment in secondary lysosomes w/ digested material
neurons communicate with other neurons at
synapses
what do neurons use for chemical signaling?
neurotransmitters
what are the special stains used on neurons?
- nissl stain
- osmium stain
- silver stain
what are the 3 main types of neurons?
- bipolar
- multipolar
- pseudounipolar
how many axons and dendrites are found in bipolar neurons?
- 1 axon
- 1 dendrite
where are the places that bipolar neurons are found?
- retina
- olfactory cells
- cochlear ganglia
- vestibular ganglia
what is the distribution of axons and dendrites in multipolar neurons?
- 1 axon
- multiple dendrites
multipolar neurons are most commonly found in the
CNS
describe pseudounipolar neurons
soma w/ single process that branches
in pseudounipolar neurons the process immediately branches into
- dorsal root ganglia
- cranial ganglia
is the soma of the CNS located in the gray or white matter?
gray
the soma in the PNS is located in the
- ganglia
- specialized sensory regions
define synapses
points of contact between neurons
what is released at synapses?
neurotransmitters
synapses can be either
excitatory or inhibitory
synapses receive input from the
environment and other neurons
synapses transmit information to
other neurons and effector cells
list 5 examples of neuroglia
- oligodendrocytes
- astrocytes
- ependymal cells
- micorglia
- Schwann cells
where are Schwann cells found?
in the PNS
what neuroglia is found in the CNS?
- oligodendrocytes
- microglia
- ependymal cells
- astrocytes
In the CNS, glial cells are more numerous than ___________
neurons
neuroglia provide ___________ & _____________ support for neurons
- structural
- nutritional
most neurons will die w/o
neuroglia
neuroglia are NOT capable of transmitting ____________ or forming _______________ but are capable of ___________.
- action potentials
- synapses
- mitosis
what is the specific marker that is expressed by neuroglia and can be used for immunohistochemical staining?
glial fibrillary acidic protein (GFAP)
oligodendrocytes form the _________ ____________ around axons in the __________.
- myelin sheath
- CNS
the myelin sheath allows for ________________ conduction of action potentials
saltatory
what is the most numerous type of neuroglia?
astrocytes
what shape do astrocytes exhibit?
a star shape
astrocytes are necessary for controlling
- extracellular movement
how do astrocytes control extracellular movements?
- removing neurotransmitters
- releasing metabolites
astrocytes communicate via
gap junctions
astrocytes have ‘end feet’ that envelop ____________ in the _________ as a part of the _______.
- capillaries
- CNS
- BBB
the BBB is
neuroprotective
The BBB is composed of
endothelial cells & astrocyte processes
the BBB restricts the passage of…
molecules & pathogens into brain tissue
ependymal cells line the ventricles of the
brain & spinal cord central canal
ependymal cells are typically
cuboidal w/microvilli
ependymal cells produce
CSF in the choroid plexus
microglia are
phagocytic cells
describe microglia
short, branched processes
microglia also contribute to the brain’s
immune protection
Schwann cells are aka
neurolemmocytes
Schwann cells form the myelin sheath of axons in the
PNS
what are the spaces between adjacent Schwann cells known as?
nodes of Ranvier
peripheral nerves are large bundles of
axons (nerve fibers)
what are the 3 layers of connective tissue in the PNS?
- epineurium
- perineurium
- endoneurium
the epineurium is the external layer composed of
dense CT
the perineurium surrounds the
bundles of fibers (fascicles)
the endoneurium surrounds each
nerve fiber
the endoneurium contains some
reticular fibers
the endoneurium is made by
Schwann cells
the CNS is protected and cushioned by the…
- skull
- vertebral column
- meninges
what are the 3 layers of the meninges?
- dura mater
- arachnoid
- pia mater
the dura mater is composed of
dense regular CT
the arachnoid meninge can be described as
- spider-like w/ a space beneath it filled by CSF
the pia mater is the __________ meningeal layer
innermost
processes of glial cells contact what layer of the meninges?
the pia mater
what cushions the brain and spinal cord?
CSF
CSF is produced by
ependymal cells in the 3&4th ventricles
CSF is high in ___________ and low in __________
- glucose
- protein
the CSF has no other cells other than the occasional
lymphocyte
CSF is reabsorbed by
arachnoid into venous system
peripheral nerves can regenerate if the soma is not
destroyed
upon injury what portion of the axon degenerates?
distal portion
axon degeneration leads to the proliferation of
Schwann cells
the proximal portion of the axon can regenerate if it connects to the
proper Schwann cell
poliomyelitis contains a virus that enters the…
motor neurons of ventral horns of the SC
with poliomyelitis paralysis can occur if
the virus kills neurons
post-polio syndrome leads with neurological issues such as
- limb weakness
- tremors
- issues speaking/ swallowing
what is a glioma?
a tumor arising from glial cells
gliomas are resistant to many
chemotherapeutic agents
alzheimer’s is a neurodegenerative disease the affects
- memory
- coordination
- ppl’s ability to function
AD is histologically characterized by
- amyloid plaques
- NFTs
amyloid plaques are
extracellular deposits of beta-amyloid
how are the plaques made?
from the abnormal proteolysis of APP
APP: amyloid precursor protein
tau under normal conditions is a
microtubule stabilizing protein
tau forms abnormal “clumps” that interfere w/
cytoskeleton’s microtubules
