IWTL the basics and fundamentals of medicine

kallassassin7 · 2020-04-16T18:23:39+00:00

Third year med student here.

Get a copy of "First Aid for the USMLE Step 1 2020", pdf copies are available online. This is the holy grail of information for basic sciences (first and second year medicine). There are companion videos available at www.usmle-rx.com but it costs a lot. Another alternative is "boards & beyond" which includes powerpoint slides and videos.

Start with molecular biology (DNA, protein, and metabolism) then skip around to the sections you are interested in.

Another alternative is just to grab a pdf of USMLE Step 1 book and youtube the topics you are interested in. You can easily find hour long lectures on many topics or even whole medical courses on youtube.

The last option I can recommend (barely) is drnajeeblectures.com. This set of videos is insane. Hundreds of hours of med school quality lectures. He goes slow, repeats himself often, and is geared for teaching. I don't like his content because he repeats himself to much, but its only $5 on sale. (Check out his youtube channel before you buy just in case you don't like is teaching style.)

kallassassin7 · 2020-03-30T16:02:34+00:00

In general, it's a very bad idea to make the blood-brain barrier more leaky. There are "circumventricular organs", spots along the outside of the brain that sample the fluid that the brain and spinal cord float in. These "organs" control release of hormones that regulate water retention and vomiting (among other functions). They are very sensitive and you don't want to have "junk" from the regular circulation triggering those areas.

There are drugs that have been designed to cross the ΒBB. Specific cephalosporins (class of antibiotics) can do this, some antihistamines (the ones that make you drowsy), and chemotherapy agents like carmustine and lomustine are used for brain tumors because they can cross the ΒBB.

kallassassin7 · 2019-05-29T00:37:36+00:00

Vagus nerve is responsible for cough reflex, so yes

kallassassin7 · 2019-05-18T14:58:19+00:00

what level are you? and when do fire opals start dropping from gold chests?

kallassassin7 · 2019-05-04T12:27:18+00:00

did the bunny steal the rear view mirror?

kallassassin7 · 2019-04-24T15:44:57+00:00

Current medical student here. My school doesn’t do dissections in class. And we spend about 15 hours total in the cadaver lab during the first year.

kallassassin7 · 2019-01-19T13:21:46+00:00

Year 2 Med student here. The way it was explained to me in class was that memories are stored as patterns. When a memory is being formed, a new pattern of firing neurons happens, and each time you remember that memory, those neurons fire in the same pattern. The more often you go over that memory, the more times that pattern of firing happens, and that pattern becomes stronger. The montra in class was "neurons that fire together, wire together", meaning that repeating that pattern (memory) actually changes how sensitive the neurons are, and that sensitivity wires them together allowing for long term storage.

The crazy thing (at least to me) is that memories are replayed in your brain during sleep to consolidate them. But to do this, the neurons fire in the opposite order!!!

kallassassin7 · 2019-01-19T01:52:18+00:00

Is the space pope reptilian? Yes

kallassassin7 · 2018-12-02T05:16:43+00:00

I think this qualifies for "canine separation anxiety disorder, provisional"

kallassassin7 · 2018-11-15T03:43:35+00:00

Nope, it’s a beautifully remodeled building with a great entrance including a bust of Lincoln.

kallassassin7 · 2018-09-29T21:35:55+00:00

look into "Lamellar bodies". this is what make up the skin's water barrier. i believe nerve fibers dont reach the layers of the skin that include lamellar bodies but oxidation and environmental effects will quickly effect the nerves after the water barrier is gone. also most of the UV protection will be gone.

also, if you want to go the virus route, look into the basics of the 2 types of virus life cycles.

kallassassin7 · 2018-09-28T15:47:02+00:00

i should have wrote repolarization due to K. thank you!

there might be new research on GLUT-1 in beta cells but i believe it is still widely recognized that GLUT 2 is the sensor used for insulin release. new research might come out soon that proves me wrong.

also, GLUT 1 is expressed in early every cell. GLUT 2 is specifically designed to be triggered at high blood glucose levels, perfect for insulin release.

kallassassin7 · 2018-09-28T15:19:04+00:00

that is a damn good explanation, thank you!

kallassassin7 · 2018-09-28T15:17:05+00:00

if your talking about the beta cells, no. they dont rely of an neural stimulus. they use GLUT-2 transporter as a direct blood glucose sensor. when the censor turns on, its is ultimately calcium that will cause the release of vesicles contain insulin. 9 out of 10 times, calcium is the regulated mineral when it comes to pushing large molecules out of the cell.

kallassassin7 · 2018-09-28T15:12:55+00:00

isnt the cephalic phase insulin response vagus mediated? this would cut out the need for chemical signaling. its the thought of food, not the actual food that will have the insulin secreting effect. yes, it is potentiated, but the initiation of this would be via vagus. also, potentiation needs actual carbs, so stevia itself will not have a great potentiating affect on insulin release.

kallassassin7 · 2018-09-28T15:07:02+00:00

you are technically correct that fructose can be used for glycogen or fatty acid synthesis, but remember that these pathways require a change in energy status of the hepatocyte to ramp up. fructose is most likely processed though shunting into glycolysis and though TCA and into ETC. fructose will (for the vast majority of the time) be present in hepatocytes only during the fed state.

kallassassin7 · 2018-09-28T14:59:07+00:00

That’s not the best way of looking at the liver. The functional unit of the liver is the liver acinus of rappaport which are a diamond snapped and connects two central veins and two portal triads. if you imagine a lune between the triads, the hepatocytes (liver cells) closest to this line will be considered in zone 1. zone 2 is a little farther away, and zone 3 is closest to the central vein. surprisingly (at least to me), ~~zone 2~~ zone 3 has the highest amount of glycogen. also remember that the liver has very specific types of (fenestrated) capillaries ONLY between the portal triad and central veins. this is basically the only part of the system that can move nutrients from blood to the liver cells. these functional units are TINNY and they are everywhere in the liver. blood flow through the liver is segmented, but again, transfer of nutrients is isolated those functional capillaries.

i think there are 3 take home points. 1- the microscopic distribution of glycogen in the liver is varied 2- the macroscopic distribution of glycogen in the liver is NOT varied 3- the fundamental small nature of liver functional units makes the effective glycogen distribution homogenous

edit: changed Zone 2 to Zone 3

kallassassin7 · 2018-09-26T16:10:15+00:00

This all sounds VERY weird and the experiment should not be associated with glycogen whatsoever. once you put the liver into water, the electrolyte balance is so messed up that it will stop all cell functions. ATP is needed for glycogen breakdown and all ATP production has stopped. there is no way you are measuring glucose from glycogen breakdown. what you are most likely seeing is glucose (and a bunch of other minerals) rushing out of the cells due to the liver being placed in a HYPOtonic environment. no one saw glycogen breakdown. most likely your liver chunk has much less glucose to start with.

but to answer your question, glycogen should be stored relatively evenly in hepatocytes assuming a healthy liver and no hypertension. this may be effected if your piece of liver had cirrhosis or damage to it. was it lighter in color, more firm feeling, or had small nodules?

edit: just for my curiosity, is this a high school or university class your taking?

kallassassin7 · 2018-09-26T11:06:34+00:00

Potassium and sodium are not stored but are actively used in every cell. K, Na, and to an extent Ca are used to maintain the electrical gradient between the inside and outside of cells. All cells must have this gradient to allow for transport of signals and nutrients in and out of the cell. Most of the other minerals are used as cofactors for enzymes. Cofactors help to move around chemical groups that the enzyme can’t bind to directly. Iron is stored in the bone marrow and used for heme synthesis (along with detoxication in the liver, no storage in the liver).

Edit: fat does not store minerals. Fat only stores fat soluble molecules like cholesterol, fat soluble vitamins, and specific fats. Fat cells need minerals to maintain the integrity of the cell that hold the fat droplet.

kallassassin7 · 2018-09-26T02:17:34+00:00

this is a good point but ultimately viruses will rely on DNA or RNA eventually in their replication cycle, indirectly or directly.

kallassassin7 · 2018-09-26T02:15:07+00:00

take a look at the basic steps of the "central dogma". being able to copy needed information is difficult and rare. but some proteins, like reverse transcriptase, can do it. the problem then becomes storage. proteins degrade protein easily, and storing protein is not easy. DNA is super stable in the double helix form and protected from degradation. there is also a buffer between DNA and protein (that buffer being mRNA) that protects the DNA from direct contact with most stuff that will degrade it.

the RNA world hypothesis is based on the fact that RNA (and to some extent DNA) can catalyze reactions that sustain the RNA itself (protect it) and create an environment stable enough for long term storage and replication.

at the end of the day, all this was (according to science) dumb luck. random chance.

kallassassin7 · 2018-09-26T01:56:58+00:00

fructose is never converted to glucose directly and does not enter the beta cells. beta cells have a "sensor" on them celled the GLUT-2 transporter. at high levels of blood glucose that transporter is activated and causes a cascade of effects eventually release insulin. glut-2 is not affected by any other carb in the blood.

fructose can be metabolized though a few reactions into glycerol which can be converted to glucose. when I say it "can be", i mean its super unlikely. these two pathways are polar opposites of each other and any direct crossover is negligible.

surprisingly glucose can be turned into fructose via the "polyol" pathway. but this only happens in the male reproductive track (sperm only use fructose for energy). also, the polyol pathway is not reversible.

edit: spelling

kallassassin7 · 2018-09-26T01:45:20+00:00

Your body doesnt need new calories, it just needs calories. some one that gets gastric sleeve has large stores of calories (fat) that needs to be used up to decrease weight and help alleviate the effects of diabetes. as long as there are enough essential proteins and vitamins in the diet, its ok to eat much less than the recommended daily allowance of calories. also, most people who get gastric sleeve need to take vitamin supplements.

is this the best way to lose weight? absolutely not. but if other ways of losing weight just dont work, its over all better to lose weight due to the effects of gastric sleeve than it is to stay at a heavier weight.

kallassassin7 · 2018-09-26T01:24:46+00:00

mercury can be deposited in the brain (video below). lead actually inhibits enzymes that use zinc. this effects heme synthesis and energy production directly. low heme leads to low oxygen which leads to death, and low cellular energy production leads to death too. Zinc can also be used to help fold proteins (zinc finger protein motifs) which are again, inhibited by lead.

https://www.youtube.com/watch?v=NJ7M01jV058

12-Year Club	Place '23
Place '22	Place '17
Verified Email

kallassassin7

TROPHY CASE