Week 1 Flashcards
synapse
point of junction between two electrically excitable cells
presynaptic bouton
vesicles and NT
postsynaptic site
receptors
synaptic cleft
ECM
adhesion proteins
astrocytes
electrical synpase
bidirectional
fast
strong
limited
chemical synpase
unidirectional
variable strength
not as fast
NT
neurochemical released by neuronal stimulation resulting in a postsynaptic response
localization mimicry release pharmacology reuptake/degradation
localization of NT
produced within neuron and found within a neuron
mimicry of NT
if chemical applied to post synaptic membrane, it should have same affect
release of NT
from neuron (depolarized)
pharmacology of NT
action on receptors; agonist and antagonist effects
reuptake of NT
inactivated of chemical after release
through reuptake or enzyme
axodendritic/axosomatic
terminal to postsynaptic receptor
pre to post forward
axoaxonic
module NT release
dendoraxonic
retrograde signaling
autapse
autocrine signaling (self regulation)
multipartite synpase
synaptic modulation
neuroglia
cells that support and protect neurons
maybe in volved in local and long distance signaling
neuron features
high metabolic rate
extreme longevity
nonmitotic (mostly)
diverse in morphology and function
dendrites
short processes that branch out from cell body
receive impulses and carry to cell body: signal input
soma
integrating center for neuronal signals
axons
transmit nerve impulses away from cell body and transmit info to other cells (signal output)
stroma cell
nucleus
nucleolus
mitochondria
free ribosomes and ER (nissl bodies)
axons
long, cylindrical processes
may branch into axon collaterals
transmit impulses away from body and transmit info to other cells (signal output)
axon hillock
region where axon connects to cell body
axon collaterals
side branches of main axon
synaptic knobs
expanded regions at tip of axon with NT containing vesicles
local circuit neurons
short, unmyelinated
projection neurons
long, myelinated
neurons can be BOTH
local and projection
microfilaments
F-actin from G actin
5nm
microtubules
tubulin dimers w associated MAPs and Tau proteins
20nm
intermediate filaments
polymerized GFAP in astrocytes - no other glial cell
10nm
int he axon the distal end of the microtubule is the
+ end
immunofluorescence microscopy
localizing proteins in brain cells
emission of visible light by substance that has absorbed light of a diff wavelenth
double label immunofluorescence
two proteins on one cell
NaCh, MAP2
dendrite structure
tapered, many branching processes
several principle dendrites and MANy dendrites
bipolar cells
one principle dendrite
size and shape of dendritic arbor
relates to connectivity with and location of connecting neurons
complexitiy relates to number of synpases
dendritic spines
more density - increased sensory experience
spiny neurons vs nonspiny neurons
exist
gray’s type 1
excitatory synapses on spine and dendritic shaft
not in soma
elaborated postsynaptic region
2 types of synapses
gray’s 1 and 2
gray’s type 2
inhibitory synapses on dendritic shaft and soma
not only in dendritic spines
spines serve as
functional compartments within cell and barriers to diffusion (calcium and protein)
spines can
change size and shape altering strength and number of contacts
synapse on spine
almost certainly excitatory
four CNS glial cell types
encased in bone
astrocytes
ependymal cells
microglial cells
oligodendrocytes
two PNS glial cell types
satellite cells
neurolemmocytes (schwann cells)
ependymal cells
line ventricles, produce and secrete CSF
form blood-CSF barrier
neural stem cell roll
precursor of neuron and astrocytes
myelin
lipid rich wrapping of glial membrane around axons to provide electrical insulation and speed action potential conduction
PNS myelin
schwann cells
one schwann cell sheaths one axon; axons are sheathed by many Schwanns
CNS myelin
oligodendrocytes
one oligodendrocyte sheaths multiple axons; axons may be sheathed by many oligodendrocytes
microglia
smallest star shaped few processes/neurites mesoderm-derived (not ectoderm) defensive/scavenger function related to macrophages dormant
how do microglia respond to injury?
mitosis
retracting processes, changing shape
produce cell signaling molecules
migrate to injury/infection site
destroy/engulf dead and dying cells
astrocytes
star shaped cells many processes/neurites have End Feet ectoderm derived (neural origin) present in CNS only
astrocyte jobs
- create 3D framework for CNS; guide neuronal migration during development
- repair damaged tissue
- maintain BBB
- provide metabolic support for neurons
- control interstitial ionic environment
- uptake of NT
astrocyte role: 3D framework
migrate along radial glia
astrocyte role: repair damaged tissue
phagocytosis
provide trophic support and repair functions for damaged neurons
astrocyte role: BBB maintenance
isolates CNS
perivascular feet to surround blood vessels in brain
astrocyte role: metabolic support
metabolic trafficking in brain cells
breakd own glucose to give neuron lactic acid to re-convert to pyruvate for use in CA
-glucose from capillary, give neurons lactate
astrocyte role: ionic balance
aquaporins to couptake K+
astrocyte role: NT uptake
take up glutamate and GABA
astrocyte and synaptic functions
- partner with neurons at Glu and GABA synapses to reuptake
- express Glu receptors themselves
- promote synapse formation with synaptogenic factors and adhesion proteins
- envelop and isolate individual synapses
BBB keeps out
infectious pathogens
immune cells
BBB allows to pass
O2, CO2, lipids
glucose, AA, vitamins, hormones
how does neuronal activity locally increase the cerebral blood flow?
vasodilation thus increasing delivery of oxygen and nutrients to working neurons
Glu fired with AP; astrocyte has mGluR
signals to vasodilate
growth cone
end of developming neuron;s neurite is a growth cone
actively expands and retracts during neurite outgrowth and axon pathfinding
growth cone filopodia
test surrounding environment and are attracted to some chemical signals but repelled by others
growth cone has surface receptors that sense attractant and repellent cues
signals are transduced in cytoplasm and guides growth
dependent on cytoplasmic calcium levels
growth cone movement and elongation is mediated by
cytoskeletal lattice in filopodia containing dynamic actin and myosin
as neurite extends, MT backbone elongates by polymerization of tubulin protein monomers
what adds membrane to both sides of lamellopodia and filopodia
fusion vesicles
SLIT
decreased motility
NETRIN
increase motility, actin polymerization, vesicle docking
chemotropism
oriented or directed growth dictated by chemical signaling
SLIT signal
global CA2+ signals: regulation of depolymerization of MT and actin
membrane vesicle endocytosis
retraction of growth cone
NETRIN signal
global Ca2+ signals: regulator of polymerization of MT and actin
membrane vesicle exocytosis
elongation of growth cone
intracellular Ca2+ regulates activity of
Rho-GTPase and effectors
Protein phosphatases (calcineurin)
Protein kinases (CAMK, PKC, AMPK) ==> inc cell cycle, survive, energy
two major classes of axon guidance cues
secreted, diffusable signals
cell-adhesion molecules
long range cues
soluble, secreted molecules
short range cues
membrane-bound, contact-mediated cues
