NEURAL Flashcards
3 functions of the NS
sense
integrate
respond
2 types of peripheral nerves
cranial
spinal
what are ganglia
collections of neuronal cell bodies
sensory neurons
peripheral -> CNS
motor neurons
CNS -> peripheral effectors
T or F: motor neurons can be voluntary or involuntary
T; based on tissue they innervate
T or F: a neuron is only either sensory or motor; NEVER both
T
target of somatic NS
skeletal muscle
T or F: somatic NS can be subconscious
T; as long as its skeletal muscle, reflex are included
targets of visceral/autonomic NS
smooth muscle
cardiac muscle
glands
T or F: subdivisions of autonomic NS are functionally and anatomically distinct
T
2 divisions of autonomic NS
sympathetic
parasympathetic
what defines the arm of NS being used
target
2 means of communication by neurons
electrical, chemical
T or F: neuroglia participate directly in communication
F: only for structural support
how do microglia support neurons
chemical support (metabolic exchange, maintain CSF) immunological defense myelin sheath (insulation)
where do graded electrical signals occur in neurons
at dendrite
what does graded signal mean
proportional to strength of stimulus
T or F: dendrites are wide reaching
F; function locally
where does integration occur in nerve
axon (integration of signals)
where on neuron are AP generated
initial segment
how many axons per cell
1 (unidirectional flow)
end of neuron
synaptic terminal
what always has fixed amplitude T or F: neurons are polarized
T (input end, output end)
what always has fixed amplitude
AP
what is special about initial segment
high concentration of voltage-gated Na channels
multipolar neurons
motor neurons (somatic and visceral) interneurons
structure of interneurons
multipolar
where is initial segment in multipolar neurons
beside cell body
bipolar neurons
special senses
retina, cochlea, vestibular apparatus
pseudo unipolar neurons
sensory neurons
where is cell body located for pseudo unipolar neurons
ganglion
where are dendrites for pseudunipolar neurons
periphery
where is initial segment in pseudounipolar neuron
beginning of axon (not adjacent to hanging cell body)
glia of CNS
astrocytes
oligodendrocytes
microglia
ependyma
glia of PNS
schwann cells
satellite cells
cell bodies: grey or white matter?
grey
composition of white matter
myelinated axons
intermediate filament in astrocytes
glial fibrillary acidic protein (GFAP)
what does GFAP detect
astrocytes in CNS
what kind of tumour could GFAP detect
fibrous astrocytomas (80% of adult brain tumours)
which glia acts like reticular fibres in CNS
astrocytes
which cell induces TJ in BBB
astrocytes
3 functions of astrocytes
foot processes -> BVs, nerves => tight junctions
structural support
chemical homeostasis ; buffer K
which glia forms myelin in CNS
oligodendrocytes
T or F: one o-cyte only contributes to 1 axon
F; can contribute to many
T or F: one CNS neuron can be myelinated by many o-cytes
T
function of o-cyte
increase rate of conduction
which glia are phagocytic cells of CNS
microglia
what lineage are microglia from
monocyte/macrophage
what activates microglia
infection, damage
where are ependymal cells
lining ventricles (brain) and central canal (spinal cord)
classify epithelium of ependymal cells
ciliated cuboidal
role of cilia on ependymal cells
propels CSF
what structure secretes CSF
choroid plexus
what forms the blood-CSF barrier
ependymal cells that cover BV in choroid plexus
what junction in CSF-blood barrier
tight junctions between ependymal cells
T or F: CSF fills ventricles and space around CNS
T
2 compartments separated by BBB
blood and interstitial fluid
what fluid bathes parenchyma of brain
interstitial fluid
T or F: interstitial fluid and CSF are continous
true; across wall of ventricle; separated by ependymal cells
capillaries in choroid plexus
fenestrated
where are TJ: lining ventricle wall or in choroid plexus?
choroid plexus ependymal cells
function of satellite cells
electrically and chemically insulate neural cell body
sensory ganglion
dorsal root ganglion
composition of myelin in PNS
many concentric layers of schwann cell membrane
how many axons does schwann cell cover
SINGLE axon (if myelinated)
how many schwann cells per axon
multiple
in myelin, where is schwann cell nucleus
squeezed to periphery (think of skeletal fibres)
where are nodes of ranvier
BOTH CNS and PNS
when does schwann cell envelope many axons
when axon = “unmyelinated”
T or F: unmyelinated axons are associated with schwann cells
T; axon in superficial groove of schwan cells
T or F; unmyelinated axons still need multiple schwann cells
T
grey matter in brain
cortical
cerebral nuclei
where does synaptic transmission occur
grey matter
grey matter in spinal cord
central butterfly
white matter in brain
tracts, columns, pathways
pathways in white matter are usually ___
crossed (crosses midline)
T or F: tracts within white matter are functionally segregated
T; sensory vs motor
what is nissl substance
RER
what is neuropil
substance in neural tissue other than neuronal cell bodies (glia, axons, dendrites)
T or F: glia cell nuclei are in white matter
T
how does myelin sheath appear on slide
empty; lipid extracted during processing
type of neuron in sensory ganglia
pseudo unipolar; both somatic and visceral
type of neuron in autonomic ganglia
multipolar (motor)
T or F: sympathetic and parasympathetic ganglia are anatomically separate
T
what type of neurons in dorsal root ganglion
sensory; so pseudo unipolar
what type of neuron has a large round cell body, central nucleus, prominent nucleolus
pseudo unipolar
type of neuron with irregular cell bodies, eccentric nuclei
multipolar
which neuron has more satellite cells: pseudo unipolar or motor
pseudo unipolar (motor/autonomic = few)
T or F: in PNS, no functional segregation
true; nerves (white matter of PNS = mixed sensory and motor)
what happens if cut off blood supply to nerves
parathesia
enclosed in endometrium
axon and its schwann cells
axon: basophilic or eosinophilic?
eosinophilic
