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4 neuron functional zones
input zone - dendrites
integration zone - axon hillock
conduction zone - axon
output zone - axon terminals
What kind of neurons make up most of the CNS?
interneurons
astrocytoma
tumor in brain or spinal cord - cancerous - astrocytes rapidly multiplying
Alexander disease
genetic mutation causes astrocytes unable to get rid of GFAP (something they produce) --> they fill up and die
Multiple sclerosis
oligodendrocyte injury from autoimmune attack
Sympathetic nervous system
fight or flight
parasympathetic nervous system
rest and digest
white matter
axon bundles - no neurons/cell bodies
gray matter
clusters of neuron cell bodies
corpus callosum
white matter
basal ganglia
Center of the brain - a bunch of neurons for movement
Parkinson's disease
basal ganglia dies
limbic system
emotional memory, regulation
cortex area
consciousness, decision-making
Midbrain function
Reticular formation - sleep, arousal, body temperature
If you go into a coma, what has failed?
The midbrain
pons function
connection of nerves to the eyes and face.
medulla function
heart rate, breathing
cerebellum function
motor coordination, learning
what part of your brain can you live without?
cerebellum
meningococcal meningitis
bacteria enters subarachnoid fluid
tumor of the dura name
meningioma tumor
subdural hematoma
blood under dura mater
what do cerebral ventricles do?
make CSF
how much CSF is produced per day?
16oz
hydrocephalus
CSF circulation failure - entire 16oz doesn't leave brain each day
how is hydrocephalus treated?
CSF drainage tube
CT scan
X-ray
Shows tissue density
MRI
magnetic fields and radio waves cause protons in brain tissue to line up
PET scan
Show brain activity
Radioactive chemicals to map destination
best neural imaging for brain tumors
PET scan
Functional MRI
Show brain activity
Detects changes in metabolic activity (ex. oxygen use)
Show how networks in brain collaborate
Diffusion tensor imaging
shows brain connections (images axons of neurons)
soma
cell body
intrinsic proteins
proteins on surface of cell membrane (receptors, channels, etc)
Kinesin transport type/direction
anterograde transport (soma --> terminals)
Dynesin transport type/direction
retrograde transport (terminals --> soma)
Lissencephaly
"Smooth brain" - microtubules fail
MELAS syndrome
Mitochondria fails --> brain can't get oxygen --> seizure
concentration gradient
Diffusion - ions flow from areas of high concentration to low concentration
Electrical gradient
Electrostatic pressure causes ions to flow towards oppositely charged areas
ion channels
proteins on membrane that allow ions to pass in/out
Gated channels open in response to? (3 things)
Voltage
Chemicals (drugs)
Mechanical action (vibration)
What ion are neurons selectively permeable to?
K+
sodium-potassium pump
3 Na+ out, 2 K+ in
What does tetrodotoxin do?
Blocks voltage-gated Na+ channels
Where are graded potentials located?
Dendrites
Where are action potentials located?
Axon
Threshold for neuron to fire
-40mV
Where is "trigger" for action potential located?
Axon hillock
Action potential when do Na+ channels open and close?
-40mV open, +40mV close
Absolute refractory phase
+40mV - no more action potentials can be produced
Relative refractory phase
While K+ channels are open and K+ is leaving - only strong stimulation can produce action potential
What is myelin's purpose?
Help action potentials regenerate FAST
What helps action potentials travel only in one direction?
Refractory period
Myelinated vs unmyelinated axons speed and energy use
Myelinated - 10x faster, and saves 40% more energy
How do action potentials cross synapse?
Chemical signals
excitatory postsynaptic potential (EPSP)
Depolarization - Na+ ions enter = more positive
inhibitory postsynaptic potential (IPSP)
Hyperpolarization - Cl- ions enter = more negative
How are ESPS and ISPS integrated?
dendrites vote, axon hillock decides
What gates on ESPS or IPSP?
chemically gated - transmitter binding causes them to open
what happens to neurotransmitters after binding?
degradation or reuptake
What is the primary neurotransmitter in muscles?
Acetylcholine
How does RAID work?
blocks acetylcholinesterase --> more acetylcholine --> more muscle action --> twitch to death
where do electrical synapses exist?
heart and some places of brain
what causes epilepsy?
injury or genetic defects on electrical synapses --> excessive firing
Ligands
Chemicals that bind to receptors to activate/block them
endogenous ligands
neurotransmitters, hormones
exogenous ligands
drugs, toxins from outside the body
Up-regulation
increase of number of receptors - sensitization
Down-regulation
Decrease in number of receptors (as a defense) - tolerance
Example of up-regulation
Nicotine addiction
example of down-regulation
benzodiazepines
Tonic-clonic seizure
Stiffness and then jerking
Loss of consciousness and violent muscle contractions
absence seizure
Happen hundreds of times a day - pausing/freezing for a couple seconds
focal seizure - impaired awareness
Barely conscious, drooling
In L/R temporal brain
myoclonic seizure
Rhythmic/repetitive muscle jerk seizure
98% chance of mental retardation
focal seizure - aware
Awake and aware, twitching
In motor cortex
glycine
Inhibitory neurotransmitter --> causes inhibition (relaxation)
Opisthotonos
generalized rigidity - glycine is blocked by tetanospasmin
Ionotropic receptor
simple, direct - open when bound by transmitter (ligand-gated ion channel)
metabotropic receptor
complicated, indirect - transmitter binds, receptor activates G-protein, binds to other proteins or ionotropic receptor
75% of drugs act on what type of receptor?
metabotropic receptors
agonist
initiate normal effects of receptor
antagonist
prevents receptor from being activated by other ligands
competitive antagonist
doesn't let other ligands bind
noncompetitive antagonist
sneaky --> binds somewhere else, makes other ligands NOT WANT TO bind
4 common amino acids
Glutamate
Aspartate
Glycine
GABA
2 types of monoamines
catecholamines and indolamines
catecholamines
dopamine, norepinephrine, epinephrine
indolamine
serotonin
soluble gases
nitric oxide, carbon monoxide
what does glutamate operate?
Sodium and Calcium ionic entry (ionotropic receptors) and mGluRs
excitotoxicity
neural injury causes excess release of glutamate --> causes neurons to kill themselves
what goes GABA do?
Inhibitory --> activates ionotropic receptors like Cl- channels
most common inhibitory neurotransmitter in brain
GABA
agonists of GABA
Valium, barbiturates
most common neurotransmitter in spinal cord
Glycine
What does glycine do?
Acts like GABA - inhibitory, binds to ionotropic receptors
catecholamine synthesis
dopamine --> norepinephrine --> epinephrine
Note 
Flashcard (20)