Medical School Resources! (and Other Humanbiology,physiology,biochemistry-related Resources)

Medical School Resources! (and other human biology,physiology,biochemistry-related resources)

Hi Everyone! 

Update: I am now officially done with my second year! I know i’ve been MIA on here for a while now - but that’s only because I was drowning in textbooks and assignments! I will be writing a whole other post on what my second year in medical school was like - so watch out for that :)

I, for one, can not just rely on one method of learning. Meaning, I’ll jump from videos, to textbooks, to flashcards. In this post I’m going to list some of my holy grail youtube channels that have helped saved me. 

1) Handwritten Tutorials

https://www.youtube.com/user/harpinmartin

Every video in this channel is short, but not so much that you feel like you’re missing out on information. Definitely one to save as a favourite!

2) Armando Hasudungan

https://www.youtube.com/user/armandohasudungan

The best thing about this channel is the fact that there are over 300 videos, covering a wide range of core topics in endocrinology, neurology, physiology and pharmacology. Another pro is the presentation of topics (otherwise considered snooze-worthy) in an artistic manner!

3) Speed Pharmacology

https://www.youtube.com/channel/UC-i2EBYXH6-GAglvuDIaufQ

Raise your hand if you’ve ever fallen asleep trying to read about the mechanism of action of opioids, their side effects and contraindications. I know I have. Fret not, for this youtube channel will introduce you to a world where pharmacology is actually interesting.

4) Wendy Riggs 

https://www.youtube.com/user/wendogg1

Wendy Riggs is a very down-to-earth professor in Northern California, and she covers a wide range of  topics in Anatomy, Physiology and General Biology. 

5) Anatomy Zone

https://www.youtube.com/user/TheAnatomyZone

A better way to learn anatomy is to supplement your textbook information with videos from this channel. The explanations and visuals provided are absolute gold.

I hope you all find these channels as helpful as I did!

In Which Dr. Baffled Tortures His Residents

I was rounding in the nursery with 2 interns today.  There are 7 babies in the nursery.  One of them had a large, hyper-pigmented nevus on his right calf.  All of the other babies have completely normal exams.  When I asked them if any of the babies had any findings on exam they said no.  I told them that one baby had a clear abnormality on the exam and they should go back in and re-examine all the babies and find it.  They examined babies and reported non-existent findings for an hour with no progress.  I then told them which baby had the findings and they then stared at that baby for 20 minutes before they found it.  The whole incident was painful to watch.

Whats the moral or the story?  A physician’s history and physical exam skills are among the most important aspects of medicine.  Without them, you’re just wandering around the diaspora throwing spaghetti at the wall and hoping something sticks.

Pharmacokinetics Overview

(Absorption and distribution of drugs)

The study of the time course of drugs and their metabolites in the body (what the body does to the drug) consisting of:

administration

absorption

distribution

metabolism

excretion

Administration

Enteral (passes through intestine)

oral (mouth)

buccal/sublingual (applied in cheek/under tongue)

Gastrosomy (surgical opening through the abdomen into the stomach)

Topical (applied directly)

Nasal

Rectal

Ophthalmic (eyes)

Parentral (injection)

Intravenous (into veins)

intramuscular (into muscles)

intradermal (within layers of skin)

subcutaneous (under the skin)

Drug molecules move around the body either through bulk flow (bloodstream, lymphatics or cerebrospinal fluid) or diffusion (molecule by molecule over short distances)

Absorption 

Passage of drug from its site of administration into plasma - important for all routes except intravenous injection.

Injection

IV = fastest route of administration

bolus injection = very high concentration of drug

rate limiting factors = diffusion through tissues and removal by local blood flow

Drugs need to pass through membranes (cell membranes, epithelial barriers, vascular endothelium, blood-brain barrier, placenta barrier etc) via

passive diffusion through lipids

carrier-mediated

passage through membrane pores/ion channels

pinocytosis (ingestion into a cell by the budding of small vesicles from the cell membrane)

Diffusion through lipid

non-polar molecules can dissolve freely in membrane lipids

the rate is determined by the permeability coefficient (P)(solubility in the membrane and diffusibility) and the concentration difference across the membrane

pH and Ionisation

Many drugs are weak acids or weak bases

exist in unionised or ionised forms

pH = balance between the two forms

ionised forms have low lipid solubility

uncharged however the drug is usually lipid soluble

ionisation affects:

rate of drug permeation through membranes

steady state distribution of drug molecules between aqueous compartments if pH difference exists between them

Therefore:

urinary acidification accelerates the excretion of weak bases and slows that of weak acids

alkalisation has opposite effect

increasing plasma pH causes weak acids to be extracted from CNS into plasma

Reducing plasma pH causes weakly acidic drugs to become concentrated in CNS, increasing neurotoxicity

Bioavailibility

Bioavailibility (F) indicates the fraction of an orally administered dose that reaches systemic circulation intact, taking into account both absorption and local metabolic degradation

determined by comparison between oral and IV absorption

affected by:

drug preparation

variation in enzyme activity of gut

gastric pH

intestinal motility

Volume of Distribution

Vd is defined as the volume of fluid required to contain the total amount, Q, of drug in the body at the same concentration as that present in the plasma, Cp

determined by relative strength of binding between drug and tissue compared with drug and plasma proteins

tight binding to tissue but not plasma –> drug appears to be dissolved in large volume –> large Vd (eg chloropromazine)

tight binding to plasma –> V can be very close to blood volume –> low Vd (eg warfarin)

ICU Materials part 1

After 4 years of volunteering in the ICU of the local hospital for respiratory diseases I’ve finally started to really understand a lot of the diagnostic procedures and the meaning of their results.

So I’ve decided to share with you some of the materials I use to study the ICU Stuff:

ABG interpretation

https://abg.ninja/abg - The site gives you a results from ABG analysis and you have to make a reading of them, then it show you if you are correct or wrong and gives you a full description why. On this site there some other very nice medical quzzes as well - Glasgow coma scale, Cranial Nerves, Basic ECG etc.

Lung function tests

http://www.ums.ac.uk/umj080/080(2)084.pdf

http://www.ics.gencat.cat/3clics/guies/184/img/–americanfamilyphysician.pdf In these PDFs the basic aproach to spirometry is described, everything you need to know when you stumble across spirometry results.

Coagulation tests

http://thrombosiscanada.ca/wp-content/uploads/2013/08/Bloody_Easy_Coag_2013.pdf

http://www.pathology.vcu.edu/clinical/coag/Lab%20Hemostasis.pdf Very consise and well writen guidelines for coagulation tests interpretations.

Chest radiology

https://lane.stanford.edu/portals/cvicu/HCP_Respiratory-Pulmoanry_Tab_2/Chest_X-rays.pdf

http://www.southsudanmedicaljournal.com/assets/files/Journals/vol_1_iss_2_may_08/how%20to%20read%20a%20cxr.pdf Basic guidelines for reading a Chest X-ray

Echography - Ultrasound Imaging

http://www.sah.org.au/assets/files/PDFs/For%20Doctors/2011-crit-care-us-heart.pdf

http://www.cardioegypt.com/cardioeg/ACSCA2014-Presentations/002001.pdf

http://www.annalsofintensivecare.com/content/pdf/2110-5820-4-1.pdf

http://www.cardiovascularultrasound.com/content/pdf/1476-7120-12-25.pdf

http://www.ccforum.com/content/pdf/cc5668.pdf Very simple and easy to understand presentations for the newbies(like me) in Ultrasound imaging. To be continued…

Molecule of the Day: Diazepam/Valium

Diazepam (C16H13ClN2O), also known as Valium, is a white solid that is of significant pharmaceutical importance. It is a member of the benzodiazepine family, which shares the similar bicyclic system comprising of a conjoined benzene and diazepine ring.

Diazepam is used to treat anxiety and panic disorders, and this is achieved by its binding to GABA receptors on neurons. This causes the active site of the receptors to become a better fit for GABA molecules, resulting in a higher binding of GABA to it. This triggers a greater influx of chloride ions into the neuron. 

Since the intracellular portion of the neuron is more negative than normal, the membrane is hyperpolarised to a greater extent. Consequently, a stronger stimulus is needed to trigger an action potential, which is created when a stimulus causes the membrane to reach the threshold potential.

Since the resting potential is now more negative, the action potential and thus firing of the neuron is less likely. This then produces the anxiolytic, sedative, amnesia-inducing, and anticonvulsant effects of diazepam. 

Diazepam can be produced by various synthetic pathways; one such one is shown below.

Requested by anonymous