Exam 1 Flashcards
function of spinal cord
receives sensory information and control movements of limbs and trunk
function of medulla oblongata
contains centers of autonomic function (digestion, breathing, heart rate, etc.)
function of pons
relays info about movemnt from cerebrum to cerebellum
function of midbrain
relays motor impulses from cerebral cortex to pons and spinal cord and relays sensory impulses from spinal cord to thalamus
what makes up the brainstem
midbrain, Pons, and medulla oblongata
function of cerebellum
controls movement, learning motor skills
what makes up the diencephalon
thalamus and hypothalamus
function of thalamus
controls most info going to the cerebral cortex from the rest of the CNS
function of hypothalamus
regulates autonomic, endocrine, and visceral output functions
function of cerebral cortex
information processing
function of hippocampus
learning and memory
part of temporal lobe
function of basal ganglia
involved in motor control, cognition, and reward
function of amygdala
autonomic and endocrine response to emotional states
part of temporal lobe
parts of limbic system
hippocampus, amygdala, hypothalamus, anterior thalamic nuclei, septum habenula, cingulate gyrus, fornix, etc.
direction: dorsal
top
direction: ventral
bottom
direction: anterior
front
direction: posterior
back
direction: rostral
“towards nostril”, more for 4 legged, in biped vaguely dorsal anterior (top front)
direction: caudal
“towards tail”, more for 4 legged, in biped vaguely ventral posterior (bottom back)
what makes up the cerebral hemispheres?
cerebral cortex, hippocampus, basal ganglia, and amygdala
what basic ideas did Cajal and Golgi disagree on?
neuronal doctrine: Cajal believes that nerves are “discontinuous independent elements” (individual cells). Golgi believes that neurons are all connected long cables that transverse the entire body (contiguous)
what are neuropil and neurites
processes from a soma (dendrites and axons)
what makes neurons hereogeneous
cell shape, number and configuration of processes (neuropil), neurotransmitters sent and received, gene expression (ion channels, receptors, firing, etc.), connectivity.
experience changes the connectivity
difference between neuropil and neurites
neurites are individual collections of axons and dendrites
neuropil are found in tissue, usually densely backed and sometimes mixed with glial cells
what does the soma do?
transcription, RNA processing, rER does translation and assembly, golgi does post-translational modification, etc
apical dendrites
the longest and most distal from soma
basal dendrites
shorter and closer to base of soma
what is in the dendrites
rER, golgi, mitochondria, microtubules
are microtubules bidirectional or unidirectional in dendrites
bidirectional
are microtubules bidirectional or unidirectional in axons
unidirectional
what is the axon initial segment
trigger zone, rich in voltage-gated ion channels
what does the axon do
propagate AP and release NTs
what is in the axon
sER, and mitochondria
(virtually) no rER or golgi –> proteins are not synthesized in axon but transported from soma
function of synaptic bouton
electric to chemical signals
short term synaptic plasticity
function of plasma membrane
compartmentalization and concentration of ion channels, receptors, G proteins, etc.
unipolar shape and location
one body at end, dendrites emerge from axon
found in invertebrates and in autonomic system
bipolar shape and location
one body in middle, one long branch of dendrites go to one end and axon to the other
found in retina (sensory)
pseudo-unipolar shape and location
one body with TWO AXONS branching out from one area, dendrites found on one end of an axon
found in dorsal root ganglia
what are the three multipolar cells
motor neuron, pyramidal cell, and purkinje cell
motor neuron shape and location
one body with multiple dendrites branching out, one long axon
found in spinal cord (motor)
pyramidal cell shape and location
triangle shaped soma with an apical dendrites at peak and basal dendrites at two smaller points, one long axon that can branch
found in hippocampus and cortex
Purkinje cell shape and location
One body with dendrites that branch HUNDREDS of times over, one axon that can branch
found in cerebellum
regions of a neuron in order of information flow
input (dendrites) –> integrative (beginning of axon) –> conducting (axon) –> output (boutons)
perforant pathway in hippocampus
entorhinal cortex –> granule cell –> CA3 –> CA1
main interneuron NT
GABA
what type of neuron is most diverse
interneurons, differ in marker proteins, developmental origin, firing patterns, and connections
knee jerk reflex
hammer stretches the quadricep tendon –> activates sensory neuron in muscle –> sends message towards spine where it diverges –> 1 the motor neuron in the quad is activated messaging from spine to muscle causing it to contract –> 2 an inhibitory interneuron is also activated in spine sending a signal to the motor neuron going from the spine to the hamstring preventing it from contracting
Principle of connectivity: divergence
1 sensory neuron stimulates many motor neurons
signal amplification
principle of connectivity: convergence
many different sensory neurons stimulate the same motor neuron to get it to fire (required to generate AP)
feedforward inhibition pathway
one neuron activates 2 more: one of them continues the path while the other is an inhibitory interneuron stopping the path.
ex: knee jerk reflex
feedback inhibition pathway
one neuron activates 2 more via axon collateral: one of them continues while the other via the collateral connects to an inhibitor interneuron that loops back to the first neuron –> signal is sent quickly and then immediately stops
axon collateral
a side branch extending from the axon of a neuron that is NOT a terminal branch
what is the resting membrane potential
-65mV
what causes the resting membrane potential
unequal distribution of Na+, K+, and Cl-
what channels are responsible for the resting membrane potential and how
Na+/K+ channels and K+ selective ion channels
pump Na+ out and K+ –> They are what create the salty banana
K+ ion channels are partially open at rest so membrane is mostly permeable to K+ and not very much to N+
is membrane potential specific to neurons? An example? What is unique to neurons?
No, heart cells have a potential.
Neurons are unique in the speed at which they can change membrane potentials.
what is the relative concentration of Na+ and K+?
salty banana; greater Na+ outside and greater K+ inside
what are local potentials
local changes in membrane potential that are not amplified (there are no V-gated ion channels present) and do not spread much
what causes local potentials
mechano- or ligand-gated channels
receptor potential
a passive potential caused by local potential
characteristics of a passive potential
amp, duration, intensity, effect, and propagation
amplitude: 0.1-10mV –> dec as moves away from stimulus
duration: brief to long
intensity: graded (vary in intensity)
effect: hyperpolarization or depolarization
propagation: passive
characteristics of an action potential
amp, duration, intensity, effect, and propagation
amplitude: 70-110mV –> constant at peak as it moves away from stimulus
duration: brief
intensity: all or nothing
effect: depolarization
propagation: active
what causes action potential
local potentials are summed up at trigger zone and cause V-gated ion channels to carry the signal forming an action potential
steps of an action potential
- local potentials are summed –> generator potential
- at threshold (-55mV) Na+ channels open quickly, Na+ rushes in
- as AP approaches peak, K+ channels begin to open slowly
- at peak, Na+ gates close
- as repolarization begins, K+ channels are now open, K+ leaves cell
- hyperpolarizaton occurs as K+ are slow to close, causing dip in V
- Na+/K+ pump resets the resting membrane potential
how is information conveyed in the brain
not the signal, but the pathway the signal takes –> AP is always the same
monogenic diseases
caused by single gene mutation
simple mendelian patterns
can be X linked
multigenic disease
complex patterns of inheritance
includes most behavioral traits
what do twin studies tell us about disease inheritance?
monozygotic twins that have a less than 100% concordance in a disease means that there is some amount of environmental factors in getting the disease (would be about 50% in dizygotic twins)
explain genetic overlap in mental disorders
overlap in molecular signatures across certain mental disorders shows a correlation of gene expression in those disorders (think schizophrenia and bipolar disorder)
Explain hypothesis driven approach
you find a gene first and then see which behavior(s) it affects; all of the diseases associated with one gene
Explain phenotype driven approach
you study a behavior first and then see which gene(s) affect it; all of the genes involved in one disease
requires that behavior is scorable
hypothesis drive approach methods
transgenic mice and virus-mediated alterations of gene activity
explain the old process for transgenic mice
take a fertilized egg, inject DNA fragment containing gene of interest –> RANDOM INTEGRATION, transplant egg into foster mother, identify transgenic mouse by PCR, make with WT, identify transgenic offspring by PCR
explain the modern process of transgenic mice
Harvest blastocyst from mice with brown coat, establish embryonic stem cell line, in vitro make cells with recombinant DNA and implant into white mouse foster mother, give offspring, interbreed offspring to produce brown mouse
Difference between transgenic and mutant mice
transgenic mice have new genes inserted, mutant mice have normal genes altered in some way
phenotype driven approach method
mutatnt mice
generate mice mutant in every gene and select those with desired behavior
what is ENU
a chemical mutagen for producing mutant mice
what does a QTL analysis accomplish
allows to determine position of a gene relative to a known SNP
microtubule diameter
25 nm
neurofilament diameter
10 nm
which filament is a type of intermediate filament?
microtubules
neurofilaments
microfilaments
neurofilaments
microfilament diameter
5-9 nm
how many filaments in a microtubule
13 protofilaments
which filament interacts with GTP
microtubules
what does GTP do in microtubules
The GTP cap stablizes the end of the filament –> the end with the cap is the growing end
the end of a microtubule with a GTP gap is the growing end or shrinking end?
growing
which filament is a GTPase
beta tubulin (microtubules)
what is dynamic instability
appearance of movement from constant growing and shrinking of microtubules and microfilaments
which fibers have dynamic instability
microtubules and microfilaments
what do microtubules do in neurons?
tracts for transporting proteins
which way do microtubules face in axons
+ towards periphery, - towards soma
which way do microtubules face in dendrites
bidirectional
what do kinesins do
move cargo on MT towards PERIPHERY
what do dyneins do
move cargo on MT towards SOMA
where is Tau found
in axons (and soma)
where is MAP2 foudn
in dendrites and soma
how does Tau cause Alzheimers
becomes hyperphosphorylated and insoluble –> forms tangles –> Az
where are neurofilaments found
axons and dendrites
which type of fiber is most stable (like bones of neuron)
neurofilaments
what do integrins do
associated with neurofilaments
receive extracellular proteins, regulate cell migration, signal bidirectionally
microfilaments monomers and number
actin 2
microtubules monomers and number
alpha and beta tubulin 13
neurofilaments number
24
what does thymosin do
actin binding protein reduces growth (stabilizes actin)
what does formin do
actin binding protein
protomote plus end growth
what does profilin do
actin binding protein
reg plus end growth at plasma membrane
what does cofilin do
actin binding protein
depolymerizes actin
what does gelsolin do
actin binding protein
severs microfilaments
what type of cells are hippocampus pyramidal cells
glutamatergic
what is the order of the hippocampus strata from dorsal to ventral
oriens, pyramidale, radiatum, lacunosum moleculare
what stratum of the hippocampus are basal dendrites found
oriens
what stratum of the hippocampus are apical dendrites found
radiatum and lacunosum moleculare
what stratum of the hippocampus has no dendrites in it
pyramidale
what are Schaffer collaterals
axons of CA3 that go to Ca1
schaffer collateral cell body stratum
pyramidale
schaffer collateral axons direction
towards CA1 (dorsal and posterior)
En passant synapse
synapse on cell body or axon stem (not at axon terminal)
what is a dendritic spine
a protrusion of the dendrite that receives signals from a single axon at the synapse
what type of neuron usually has dendritic spines
excitatory neurons
glutamatergic synapses
how are dendritic spines plastic
they allow for structural and functional plasticity by changing axon contacts (important for learning)
what do dendritic spines do
limit diffusion of a signal, insulating a single signal from the surrounding ones
what does forming of new dendritic spines indicate
the formation of new LONG TERM memories
what is the purpose of the N-terminal sequence
penetrate the ER (later become an integral membrane protein)
what is co translational transfer
created by the sequence and cleavage
allows ribsome to create protein into lumen of ER
what is a stop transfer sequence
area of the chain that stays in the membrane (before is in outside cell, after is in cell)
made of hydrophobic amino acids
how do you get a cell with multiple integral membrane domains
alternating series of insertion and stop transfer sequences
what does PIP2 -> PIP3 do
recruits PH domains
allows cytoplasmic proteins to associate with membrane proteins
N-acylation
post- or co- translational?
reversible?
co
irreversible
Palmitoylation
post- or co- translational?
reversible?
post
reversible
cysteine
Isoprenylation
post- or co- translational?
reversible?
post
irreversible but can be masked
Phosphorylation
post- or co- translational?
reversible?
post
reversible
Ser, Thr, and Tyr
Ubiquitination
post- or co- translational?
reversible?
post
reversible sometimes
mono-ubiquitination vs poly-ubiquitination
mono signals degradation of membrane receptors
poly signals degradation of proteins by lyso- or proteasomes
where is prostranslational modification done for extracellular proteins
ER lumen
name the 4 post translational modifications of extracellular proteins
cleavage of signal peptides
n-linked glycosylation
o-linked glycosylation
GPI-anchors
what do dendritic mRNAs code for?
neurotransmitter receptors
scaffolding proteins
signal transducing enzymes
remember it is in the DENDRITES
how can dendritic mRNAs be regulated
by neural activity or synaptic stimulation
how do mRNAs get to the dendrites
in large granules containing mRNA, RNA-binding proteins, ribosomes, and translational factors along microtubules
what does Fragile X syndrome cause
mental retardation, most common cause in men and significant in women
fragile x syndrome cause
FMR1 gene triplet is repeated more than usual –> incorrect methylation and absence of functional FMRP protein
fragile x syndrome cellular phenotype
more dendritic spines
thinner elongated spines
impaired synaptic plasticity
what are ion channels
integral membrane proteins that allow ions to move across cell membrane –> they are fast
what mediates neural currents?
ions
what mediates electric currents?
electrons
what determines hydration shell size
charge and size of ion
smaller ions have larger hydrations shells
which is smaller, Na+ or K+? what about with hydration shells?
Na+ is smaller by itself, K+ is smaller with hydration shells
“smaller ion smaller mobility”
how do channel gates desensitize
it goes into an inactivated state that is different from the resting state preventing opening of the gate
how to ion channels generally open? what is different for v-gated ion channels?
generally a change in tertiary structure, in v-gated a ball and chain model is used
6 different ways ion channels can be stimulated
neurotransmitter/ligand gated G-protein coupled NT receptors phosphorylation V-gated mechanoreceptors (stretch or pressure) acid/proton- gated
what is an agonist
it binds to the same site as the endogenous ligand and activates it
what is an antagonist
competes with endogenous ligand (binds same spot) but does not activate
what is an allosteric modulator
binds at a different site as endogenous ligand and changes affinity of site for endogenous ligand
heteromeric vs homomeric vs single protein with repetitive element channels
heteromeric - multiple different proteins make up 1 channel
homomeric - multiples of the same protein make up 1 channel
repetitive elements - one protein that folds over and over makes up 1 channel
V gated Na+ and Ca2+ channels # of homologs # of transmembrane domains (hetero or homo) activating stimulus
homologs: 1
transmembrane domains: 24 (4*6), hetero
stimulus: membrane potential
V-gated K+ channels # of homologs # of transmembrane domains (hetero or homo) activating stimulus
homologs: 4
transmembrane domains: 6 (inward rectifying: 2), homo
stimulus: membrane potential (inward rectifying: GPCRs)
which is faster, NT gated ion channels or NT gated GPCRs?
ion channels
glutamate gated-ion channel
NT gated ion channel
GABA-A receptor
NT gated ion channel
nACh receptor
NT gated ion channel
5-HT3 receptor
NT gated ion channel
Glycine receptor
NT gated ion channel
metabotropic glutamate receptor
NT GPCR
GABA-B receptor
NT GPCR
mACh receptor
NT GPCR
5-HT receptor
NT GPCR
dopamine receptor
NT GPCR
norepinephrine receptor
NT GPCR
an outside out patch exposes which side to the drug
outside
an inside out patch exposes which side to the drug
inside
what does the presence of a ligand to its channel
increases the PROBABILTY of it opening
what does a variety of voltages in a cell show
there is more than one type of channel present
ohms law
I = V/R
conductance
conductance = I/V or 1/R
resistor like channels
have the same ease for current to flow in or out
have straight I/V curve
Ohmic channels
same as resistor like
have the same ease for current to flow in or out
have straight I/V curve
outward rectifying
line bends away from origin
conducts in outward direction easier
+ ions move out of cell
- ions move into cell
inward rectifying
line bends towards origin
conducts in inward direction easier
+ ions move into cell
- ions move out of cell
what determines the resting membrane potential
selectivity of ion resting channels
concentration of permeable ions
leak K+ channels, HCN channels, IRK channels, Na+/K+ pump, GABA-A receptors
At rest, is intra or extra cellular more positive?
excess + outside
depolarization ion movement
+ in
- out
hyperpolarization ion movement
+ out
-in
when are resting channels open
all of the time
what channels form the AP and when
resting channels form resting potential
ligand gated get to threshold
past threshold, V gated form AP
what is the chemical driving force
outward movement of K+
the resting membrane potential generated by K+ moving down its conc gradient
what is the electrical driving force
inward movement of K+
are there V gate channels in glial cells
no
what affects the nerst equation
gas constant temp valence of ion faraday constant extracellular conc of ion intracellular conc of ion
at rest, which way do ions flow
opposite their concs –> Na flow in, K flow out
Na+ has a greater effection on the membrane potential
the goldman equation
takes into account all relative permeabilites and concentrations
outward over inward, except for K
how is resting potential maintained
ions always flow down gradient, active transport counterbalences this
high permeability
high conductance low resistance
low permeability
low conductance high resistance
adding more neg charge
hyperpolarization
