Neuro Exam 1.11
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Neuro Exam 1.11
neuroscience neuroanatomy neurology
review of neuro lecture 11 for exam 1
increased levels of K in blood
What causes hyperkalemia?
renal failure (kidneys don't filter K)
What happens during hyperkalemia?
concentration gradient causes diffusion into interstitial space
changes in ratio of intracellulr to extracellular K
shift in RMP that decreases intracellular negativity
RMP closer to threshold, so easier to generate AP
Causes excessive contractions of smooth mm
What symptoms occur during hyperkalemia?
cramping of GI tract
: very rapid HR --heart won't fill (can result in death)
decreased level of K in blood
What causes hypokalemia?
excessive dehydration, vomiting, diarrhea, etc.
What occurs during hypokalemia?
migration of K from interstitial to intravascular (blood) --trying to reach equilibrium
ratio increases causing hyperpolarization
RMP farther from threshold, so harder to fire
What does hypokalemia cause?
decrease in activity of muscle (bradycardia, decreased peristalsis, and constipation
Lidocaine chemical binds to:
voltage-gated channel on receptor organs and axons of passage
What does lidocaine do?
closes Na voltage-gated channels
What does closing Na voltage-gated channels do?
Na can't pass through channel
depolarization can't occur, therefore no graded potential or AP
What is lidocain used for?
naturally occurring plant compound that binds to nicotinic receptor sites
What is the synthetic version of curare used in anesthesia?
What does curare compete with?
What does curare compete with ACh for?
Curare acts as an antagonist to:
If curare is injected, it:
competes for nicotinic receptors associated w/ MEP, and skeletal mm can't contract
What does curare do to mm?
What is curare used in?
Succinylcholine is similar to:
What is succinylcholine?
What does succinylcholine prevent?
AP in skeletal mm
Succinylcholine is an anesthetic to:
paralyze the pt during surgery
To reverse the anesthesia effects of succinylcholine, pts are given:
Anticholinesterase drugs prevent:
action of ACh-esterase
What is ACh-esterase?
enzyme that naturally breaks down ACh
What are some examples of anticholinesterase drugs?
Anticholinesterase drugs increase the volume of:
ACh in NMJ
What do anticholinesterase drugs do in the synaptic cleft?
increase skeletal mm contractions
Anticholinesterase drugs prolong:
mm contractions b/c you aren't breaking down ACh
When ACh isn't breaking down, what happens?
leads to convulsions and respiratory distress (respiratory arrest)
suffocation if diaphragm is involved
What is Anticholinesterase drug used for?
antidote for chemical warfare agents
to treat myasthenia gravis
neuromuscular disorder characterized by variable weakness of voluntary mm
Myasthenia gravis improves w/:
Myasthenia gravis worsens w/:
What mm does myasthenia gravis cause weakness and fatigue to?
extrinsic eye mm (causing double vision)
Myasthenia gravis causes destruction of:
ACh receptors on postsynaptic membrane at MEP (Ach can't bind and AP can't continue)
You treat myasthenia gravis w/:
How is myasthenia gravis discovered?
lesion on skeletal mm
What type of disease is myasthenia gravis?
progressive, autoimmune disease
Botulinum toxin is produced by:
clostridium botulinum bacteria
Botulinum toxin prevents:
release of ACh at NMJ by blocking calcium at presynaptic membrane
What does botulinum toxin paralyze?
What does botulinum toxin prevent by paralyzing the presynaptic membrane?
release of toxin into cleft by blocking Ca ligand channels
What happens if there is no release of ACh?
no end plate potential of sarcolemma of mm and can't contract (paralyzed)
What is botulinum toxin commonly known as?
What does no influx of Ca cause?
no fusion pore comples
no transmission of AP
no mm contraction (if diaphragm, can suffocate)
What is a diluted form of botulinum toxin used for?
botox, called a pharmacological dennervation (lasts 3-4 mo)
If not treated for botulinum toxin, you die of:
Nerve gases function as:
inhibitors of AChase
What do nerve gases cause?
increase in ACh
What does the increased ACh from nerve gases result in?
activity of effector organs:
lacrimal glands, salivary glands, cardiac mm, skeletal mm
Nerve gases cause the lacrimal glands to:
Nerve gases cause the salivary glands to:
Nerve gases cause the cardiac mm to:
tachycardia, leads to heart failure
Nerve gases cause the skeletal mm to:
go into seizure
What is an antidote to nerve gases?
What is atropine?
an ACh antagonist
What does prozac block?
reuptake of serotonin
The blocking of reuptake of serotonin from prozac involves:
pre and post-synaptic membranes
Blocking of reuptake of serotonin from prozac occurs via:
Blockage of reuptake of serotonin allows:
serotonin to remain in receptor
Prozac may have a positive effect for what disorder?
depression, but it could cause side effects elsewhere
What does Aspirin come from?
What is aspirin useful in?
What does aspirin break down to reduce pain?
What does prostaglandin do?
activates Na channels
Aspirin doesn't transmit what kind of info?
Aspirin causes neurons to not convey:
pain to NS