\#what is between the bone and brain, denser than brain, not as dense as bone?
blood
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\#Magnetic Resonance Imaging (MRI)
1) strong magnets cause protons in brain tissue to line up parallel 2) pulse of radio waves knocks protons over 3) protons reconfigure, emit radio waves that differ by tissue density
ONLY STRUCTURE *white areas \= abnormal
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\#Positron Emission Tomography (PET)
brain activity; use radioactive chemicals in bloodstream and maps destinations by emissions (shows activity) ; which regions contribute to specific functions; functional CT
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\#Functional MRI (fMRI)
METABOLIC ACTIVITY; detect brain metabolism changes, like oxygen use; can show how networks of structures collab; FUNCTIONAL activity of brain (super useful)
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\#nucleus
DNA in chromosomes, mRNA transcribe from DNA, gene expression
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\#rough ER
membranes with ribosomes, site of protein synthesis
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\#smooth ER
regulate cytoplasm
Golgi - stacks of flat membrane compartment packaging products for shipment
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\#neuron membrane
lipid bilayer surrounds cell and separates cytoplasm from ECM; charge separator
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\#instrinsic proteins
receptors, ion channels; gives properties for signaling
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\#microtubules
spirals of tubulin; tracks for movement within neuron; railroad tracks (STATIONARY)
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\#neurofilaments
static support structures
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\#microfilaments
associated w/cell membrane; double helix actin
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\#anterograde transport (what protein?)
kinesin is the enabling protein that allows material to move from soma to terminals along microtubules; MOST MOLECULES are using kinesin
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\#retrograde transport (what protein?)
dynein enables material from terminals to soma along microtubules
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\#vesicles have
neurotransmitters
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\#neuron cytoskeleton
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\#larger axon characteristics
more complexity, more distance, faster signal
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\#sequence of signals
synapse to synaptic cleft to neuronal membrane to ion channel
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\#electrostatic pressure
causes ions to flow to oppositely charged areas (electrical gradient)
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\#resting potential
selectively permeable to K+; at rest K+ ions move into negative inside and build up, will diffuse out along concentration gradient (-60 mV)
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\#sodium potassium pump
pumps Na+ out and K+ in to maintain resting potential; uses 40% of your brain's energy; if fails, brain dies
action potentials increase in frequency with increased stimulus strength
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\#hillock (soma to axon)
action potential starts here
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\#action potentials increase in what, when stimulus is strengthened?
frequency
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\#graded potentials start at the
synaptic site of the dendrite
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\#during the absolute refractory period of the Na+ channel
the inactivation gate closes and blocks Na+ from passing
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\#action potentials travel in one direction because of
refractory state after depolarization
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\#channelopathy
genetic abnormality of ion channels; epilepsy, migraine, weakness
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\#when the neurotransmitter binds to the postsynaptic receptor it will cause an
EPSP (more Na+ enters) or IPSP (more Cl- enters)
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\#if all IPSPs and EPSPs balance, the determination of action potential will depend on
how close the Na+ ion channel or Cl- ion channel is to the axon hillock; the closer will dictate the event that occurs
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\#at the axon hillock there needs to be
enough charge at that location exactly to fire
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\#transmitters can bind to presynaptic autoreceptors which
decrease the release of the transmitter; after binding will degrade or reuptaken
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\#electrical synapses
ion flow directly into adjacent neurons; no time delay,; faster, synchronized, saves energy (in epilepsy there is a chemical change to this kind of structure); ions pass freely between (problem: every room has the door open; no selectivity)
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\#ligands fit receptors to
activate or block them; lock and key
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\#endogenous ligands
neurotransmitters and hormones (ex. ACh)
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\#exogenous ligands
drugs and toxins from outside body
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\#up-regulation
increase in number of receptors (ex: NICOTINE receptors when start smoking; sensitization)