Today I am giving you a quiz. I only see it as fair. I have to take them, and would like you to experience the joy... Good luck.
(Quiz is on the right)
Saturday, September 27, 2008
Monday, September 22, 2008
hierarchy
there is a hierarchy in medicine. at the top of this pyramid are the neurosurgeons who think they are God. its because, as far as our medical abilities are concerned, they pretty much are. they push the limits of medicine and save lives that no one else can.
the other day we had a lecture from a neurosurgeon. he said something that will stick with me for the rest of my medical career.
"The biggest mistake in medicine is not listening to the mom."
-Dr. Letarte M.D. Neurosurgeon
the other day we had a lecture from a neurosurgeon. he said something that will stick with me for the rest of my medical career.
"The biggest mistake in medicine is not listening to the mom."
-Dr. Letarte M.D. Neurosurgeon
Saturday, September 20, 2008
drug origins
i'm constantly amazed where drugs come from. some are from plants, some are from animals, some are made in a labratory, some are found in nature and then modified in labratories.
this one has a pretty cool history
Ergotamine: this is a medicine used to abort migraines once they have started. it is a partial agonist at 5-HT (serotonin) receptors, causing vasoconstriciton and suppression of meningeal nociceptive pathways.
History: derived from a fungus called claviceps purpurea, which infects grain. People would eat this invected grain and have prolonged vasospasms, gangrene, paresthesias, and spontaneous aborthions. It was known as St. Anthony's fire, because for relief of the disease, people would pilgramage to St. Anthony's shrine. In reality, they would be healed from this because they were eating a fungus-free diet on their pilgramige.
Other drug derivations.
Opioids: Poppy seeds. This group includes morphine, codine, and heroin.
Atropine: an antimuscarinic drug used to decrease the parasympathetic nervous system. it is derived from the plant Atropa belladonna. This plant got its name because ectracts from the plant were used by Italian women to dilate their pupils, a very attractive trait (apparently). I know thats the first thing i look at when i see a beautiful woman... her pupil size. mmm... i love me some big pupils... big, bilateral, dilated pupils... ok, i better stop. im going to get in trouble for this one.
this one has a pretty cool history
Ergotamine: this is a medicine used to abort migraines once they have started. it is a partial agonist at 5-HT (serotonin) receptors, causing vasoconstriciton and suppression of meningeal nociceptive pathways.
History: derived from a fungus called claviceps purpurea, which infects grain. People would eat this invected grain and have prolonged vasospasms, gangrene, paresthesias, and spontaneous aborthions. It was known as St. Anthony's fire, because for relief of the disease, people would pilgramage to St. Anthony's shrine. In reality, they would be healed from this because they were eating a fungus-free diet on their pilgramige.
Other drug derivations.
Opioids: Poppy seeds. This group includes morphine, codine, and heroin.
Atropine: an antimuscarinic drug used to decrease the parasympathetic nervous system. it is derived from the plant Atropa belladonna. This plant got its name because ectracts from the plant were used by Italian women to dilate their pupils, a very attractive trait (apparently). I know thats the first thing i look at when i see a beautiful woman... her pupil size. mmm... i love me some big pupils... big, bilateral, dilated pupils... ok, i better stop. im going to get in trouble for this one.
Tuesday, September 16, 2008
MSG
MSG? yeah, that flavor enhancer in your panda express known as monosodium glutamate. it actually kills cells in the arcuate nucleus in your hypothalamus. so what? well, turns out the hypothalamus does a lot. that nucleus specifically controls feeding behavior. so, when you kill those cells, you eat a lot, which leads to obesity. hum... so that is why i want to eat so much orange chicken and fried rice.
other neclei in the hypothalamus.
preoptic n. controls temperature.
posterior hypothalamus n. controls shivering and autonomics
suprachiasmatic n. controls your circadian rhythm (entrained by light, taking the retinothalamic pathway
dorsal medial n. also contributes to circadian rhythm but is entrained by feeding schedule
lateral hypothalamus releases orexin which makes you eat. it receives signals from the arcuate n. in form of neuropeptide Y and AGRP which are orexic (they make you want to eat) as opposed to anorexic ( you know what this means).
other neclei in the hypothalamus.
preoptic n. controls temperature.
posterior hypothalamus n. controls shivering and autonomics
suprachiasmatic n. controls your circadian rhythm (entrained by light, taking the retinothalamic pathway
dorsal medial n. also contributes to circadian rhythm but is entrained by feeding schedule
lateral hypothalamus releases orexin which makes you eat. it receives signals from the arcuate n. in form of neuropeptide Y and AGRP which are orexic (they make you want to eat) as opposed to anorexic ( you know what this means).
Thursday, September 11, 2008
Kluver-Bucy Syndrome
jeff, this one is for you.
examples of animals with kluver-bucy syndrome
crazy disease with absurd symptoms, do read on.
this is a disease caused by a bilateral lesion in the temporal lobe, including the amygdala, temporal neocortex, olfactory cortex and hippocampus.
symptoms:
visual agnosia: all objects, living or not, familiar or not, food or feces, are approached and compulsively examed, often orally
Oral tendencies: everything is compulsively put into the mouth, licked, chewed and smelled
Loss of fear and anger
Hypersexuality: male monkeys with this disease display frequent erections and copulate with other monkeys (male or female) whenever possible.
examples of animals with kluver-bucy syndrome
Wednesday, September 10, 2008
the blind can see!
no, i'm not jesus, nor did i discover a new way to heal the blind. they actually can see. let me explain.
the world around us enters the eye as light, falls on the retina then travels in the optic nerve, the optic chiasm (where it gets all switched up) and then the optic tract to the Lateral Geniculate. from here, the visual information is sent through the optic radiation (inferior visual field via the geniculocalcarine tract and the superior visual field via Meyer's loop) to the occipital lobe of the brain.
if someone has an infarct of the posterior cerebral artery affecting the occipital lobe (the part of our brain that processes visual information) then they have cortical blindness. they can't see anything.
however, if you throw a ball at their head, they will duck, or catch it! trust me, i tried it. how?
remember the lateral geniculate i mentioned? well, not only does it send off the optic radiation to the occipital lobe, but it also sends fibers through the brachium of the superior colliculus to the superior colliculus (SC). from the SC originates the tectospinal tract. this is the tract (or group of nerves) that allows us to respond to a stimuli such as a ball thrown at our head.
in the blind person, they have a lesion that occurs after this branch to the superior colliculus. thus, they duck the ball, or worse, catch it and throw it back! another way to test this phenomenon is to hold a pen in front of the blind person. 9 times out of 10 they will be able to tell you if it is pointing up or down.
so, im not advicating that you throw things at blind people, but i thought i would share this very cool bit of info with you. hope you enjoyed!
the world around us enters the eye as light, falls on the retina then travels in the optic nerve, the optic chiasm (where it gets all switched up) and then the optic tract to the Lateral Geniculate. from here, the visual information is sent through the optic radiation (inferior visual field via the geniculocalcarine tract and the superior visual field via Meyer's loop) to the occipital lobe of the brain.
if someone has an infarct of the posterior cerebral artery affecting the occipital lobe (the part of our brain that processes visual information) then they have cortical blindness. they can't see anything.
however, if you throw a ball at their head, they will duck, or catch it! trust me, i tried it. how?
remember the lateral geniculate i mentioned? well, not only does it send off the optic radiation to the occipital lobe, but it also sends fibers through the brachium of the superior colliculus to the superior colliculus (SC). from the SC originates the tectospinal tract. this is the tract (or group of nerves) that allows us to respond to a stimuli such as a ball thrown at our head.
in the blind person, they have a lesion that occurs after this branch to the superior colliculus. thus, they duck the ball, or worse, catch it and throw it back! another way to test this phenomenon is to hold a pen in front of the blind person. 9 times out of 10 they will be able to tell you if it is pointing up or down.
so, im not advicating that you throw things at blind people, but i thought i would share this very cool bit of info with you. hope you enjoyed!
Monday, September 8, 2008
random facts
your brain grows! if you practice a certain motion, the part of your brain that corresponds to that motion actually becomes thicker. with all of the complex movements that i practice each day, think of how thick my brain must be!
spacticity is a upper motor neuron sign characterised by increased tone, unequally between muscles, especially anti-gravity muscles: upper limb: flexors > extensors. lower limb, extensors > flexors.
rigidity is an increased tone seen equally in flexors and extensors. its caused by a lesion in the extrapyramidal system (basal ganglion)
what is a Bloodgood cyst? the same thing as a cyctic mastitis, adenosis, bluedomed cyst, and Schimmelbusch disease. it is a cystic mastopathy found on the breast. (breast exams begin tomorrow)
spacticity is a upper motor neuron sign characterised by increased tone, unequally between muscles, especially anti-gravity muscles: upper limb: flexors > extensors. lower limb, extensors > flexors.
rigidity is an increased tone seen equally in flexors and extensors. its caused by a lesion in the extrapyramidal system (basal ganglion)
what is a Bloodgood cyst? the same thing as a cyctic mastitis, adenosis, bluedomed cyst, and Schimmelbusch disease. it is a cystic mastopathy found on the breast. (breast exams begin tomorrow)
Saturday, September 6, 2008
muscle relaxants, receptor reserve and lethal injection
there are two types of neuromuscular relaxants (that i have learned, there are probably many more). one kind inhibits your muscles from being activated but depolarization occurs, one kind depolarizaiton does not occur.
Non-depolarization: (pancuronium, tubocurarine, vecuronium, mivacurium, rocuronium) this type works by binding to the nicotinic receptors and not allowing acetylcholine to bind. this drug demonstrates competitive, reversible binding.
depolarizing drugs: (ie succinylcholine) allows the muscle cell to be depolarized, but doesn't allow the sodium channels to be reactivated, and thus you get no more muscle contraction.
receptor reserve: this is a bit of a dificult concept. a ligand (drug) binds to its specific receptor at its target tissue. sometimes, to get a maximal effect, you dont have to have a drug binding to all the receptors. so, say you have a complete effect of the drug with only 80% of the receptors bound to drug, you have a receptor reserve (receptors unbound).
drugs like non-depolarizing neuromuscular relaxants bind to the receptor and inhibit a normal physiologic action, muscle contraction. however, if enough acetylcholine is present, you can still get muscle contraction.
diferent tissues have diferent levels of receptor reserve, and for very good reason. small fine muscles (facial expression) have the lowest reserve, so they will be affected first by these drugs. large muscles (leg and trunk muscles) have medium receptor reserve, so they will be affected next. lastly comes the diaphragm (the muscule that allows you to breath). it has the highest receptor reserve, meaning it will be the last one to be affected by this drug, which interestingly enough comes from a south american plant used by indians on the tips of arrows to kill animals. so, God designed our bodies to preserve life.
lethal injection: tubocurarine, a non-depolarizing muscle relaxant with a duration of action greater than 60 min and metabolized by the liver and kidney, is used for lethal injection. it paralizes your diaphram and you sufficate. yikes!
sorry for ending on such a depressing note. on friday we started the beautiful day with a lecture on death and the process of dying. happy thoughts...
Non-depolarization: (pancuronium, tubocurarine, vecuronium, mivacurium, rocuronium) this type works by binding to the nicotinic receptors and not allowing acetylcholine to bind. this drug demonstrates competitive, reversible binding.
depolarizing drugs: (ie succinylcholine) allows the muscle cell to be depolarized, but doesn't allow the sodium channels to be reactivated, and thus you get no more muscle contraction.
receptor reserve: this is a bit of a dificult concept. a ligand (drug) binds to its specific receptor at its target tissue. sometimes, to get a maximal effect, you dont have to have a drug binding to all the receptors. so, say you have a complete effect of the drug with only 80% of the receptors bound to drug, you have a receptor reserve (receptors unbound).
drugs like non-depolarizing neuromuscular relaxants bind to the receptor and inhibit a normal physiologic action, muscle contraction. however, if enough acetylcholine is present, you can still get muscle contraction.
diferent tissues have diferent levels of receptor reserve, and for very good reason. small fine muscles (facial expression) have the lowest reserve, so they will be affected first by these drugs. large muscles (leg and trunk muscles) have medium receptor reserve, so they will be affected next. lastly comes the diaphragm (the muscule that allows you to breath). it has the highest receptor reserve, meaning it will be the last one to be affected by this drug, which interestingly enough comes from a south american plant used by indians on the tips of arrows to kill animals. so, God designed our bodies to preserve life.
lethal injection: tubocurarine, a non-depolarizing muscle relaxant with a duration of action greater than 60 min and metabolized by the liver and kidney, is used for lethal injection. it paralizes your diaphram and you sufficate. yikes!
sorry for ending on such a depressing note. on friday we started the beautiful day with a lecture on death and the process of dying. happy thoughts...
Thursday, September 4, 2008
Wednesday, September 3, 2008
mirror neuron system
i must appologize to those who check my blog regularly. we had a test last week, so i took the rest of the week off, sort of, and didn't really learn a whole lot. this last weekend i was rock climbing in red river gorge. so, today marks my return to the books.
what i learned today... pretty amazing, your going to like this one. so when we move our hand, or feel pain in our leg, a certain part of our brain is activated. there are parts of our brain devoted to motor and parts devoted to sensory. (not impressed yet, just wait) so, it turns out that when we watch someone else throw a ball, the same part of their brain that caused them to throw the ball is activated in our brain! we are trying to learn what they did, what they felt, etc. if we see someone break their leg, the same sensory part of our brain is activated as theirs. feeling disgust from smelling a bad ordor and observing disguest in another person activates the same part of the insular cortex. this is termed the "mirror neuron system"
it has been proposed that a malfunctioning mirror neuron system is the cause of symptoms of autistic children. they may understand the intentions of others cognitively but lack the mechanism for understanding them experientially. just my speculation, but i think this might also explain why some people (usually women, and especially moms) are better at empathizing with people. maybe they have a higher developed mirror neuron system?!
what i learned today... pretty amazing, your going to like this one. so when we move our hand, or feel pain in our leg, a certain part of our brain is activated. there are parts of our brain devoted to motor and parts devoted to sensory. (not impressed yet, just wait) so, it turns out that when we watch someone else throw a ball, the same part of their brain that caused them to throw the ball is activated in our brain! we are trying to learn what they did, what they felt, etc. if we see someone break their leg, the same sensory part of our brain is activated as theirs. feeling disgust from smelling a bad ordor and observing disguest in another person activates the same part of the insular cortex. this is termed the "mirror neuron system"
it has been proposed that a malfunctioning mirror neuron system is the cause of symptoms of autistic children. they may understand the intentions of others cognitively but lack the mechanism for understanding them experientially. just my speculation, but i think this might also explain why some people (usually women, and especially moms) are better at empathizing with people. maybe they have a higher developed mirror neuron system?!
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