Did you know?

[Doctor Ali]

I'm opening this thread in terms for educational purposes; particular for USMLE Step 1. Everyone is welcome to write, share, comment, and/or give a thought in terms of Medical Education. Again this thread is meant for MEDICAL EDUCATION - NOT meant for thrashing or bashing each. This is for Medical Education Thread and I'm asking to keep it as clean as it suppose to be. When someone wants to start a new topic, it would be a good idea to start with "Did you know?" and from there, start discussing. This is meant to HELP people around for Step 1. All the best!!!!!!

[Doctor Ali]

Haha yes, physio can look like a very daunting subject to comprehend. BUT, put in the hard work and it's a piece of cake. (It's not the cardiovascular aspect of it that sucks, it's Renal and Acid/Base that SUCKS).

I couldn't agree more. CVS Physio was by far my favorite topic in any course thus far.


And yes, I believe merlindoc's point is worth reiterating. The amount of effort it takes to get to that point is astounding. From far away it likes like an extremely daunting task, but if you take it one day at a time then you can handle it no problem.

Renal Physiology does sucks. As matter a fact, the entire chapter of Renal Physiology itself sucks so badly that every time when I reached Acid - Base, I just close the book!!! Because my brain cells becomes dry as it was secreting and excreting and NOT MY KIDNEYS!!!!!! Now That sucks!!!!

[Doctor Ali]

Pretty soon Dr. Ali will be writing a physio book. :P

Never know. I might be GOLJAN # 4.

[Doctor Ali]

Did you know?


Neurotransmitter changes with disease.


1. When someone has ANXIETY, there will be:

A. Increase Norepinephrine

B. Decrease GABA

C. Decrease Serotonin (5 - HT)



2.When someone has Depression due to breakup with a girl , He will have:

A. Decrease Norepinephrine

B. Decrease Serotonin (5 - HT)

C. Decrease Dopamine



3. When someone has Alzheimer's dementia, there will be:

A. Decrease ACh



4. When someone has Huntington's disease, there will be:

A. Decrease GABA

B. Decrease ACh

C. Increase Dopamine



5. When someone has Schizophrenia, there will be:

A. Increase Dopamine



6. When someone has Parkinson's disease, there will be:

A. Decrease Dopamine

B. Increase Serotonin (5 - HT)

C. Increase ACh





Recall the following:


Serotonin is formed by Tryptophan by the following mechanism:


1. Tryptophan + Tryptophan - 5 - Hydroxylase = 5 - Hydroxytryptophan


2. 5 - Hydroxytryptophan + Aromatic L - amino acid decarboxylase = 5 - Hydroxytryptamine (Serotonin)


5 - Hydroxytryptamine = 5 - HT = Serotonin





Parkinson's disease, there is degeneration of Dopaminergic neurons that use D2 receptors.



Schizophrenia involves increased levels of D2 receptors.



GABA (Inhibitory) is converted from Glutamate (Excitatory) by the following reaction:

Glutamate + Glutamate Decarboxylase = GABA


Glutamate excitotoxicity → Glutamate is released in the Striatum and binds to its receptors in striatal neurons, resulting in an action potential. Glutamate is removed from the extracellular space by astrocytes. In Huntington’s disease, Glutamate is bound to NMDA receptor, resulting in an influx of Calcium ions and subsequent cell death.


For more information on RECALL, please see my posts # 43 and # 47

[windsorstudent]

@ Doctor Ali

Wow!! I cannot thank you enough!! Excellent post!!! You make physiology easier

[Doctor Ali]

Did you know?



1. Sugar acid is Ascorbic acid, which is Vitamin C.

Prolonged deficiency of Vitamin C are as follows:

A. Perifollicular petechiae

B. Corkscrew hairs

C. Bruising

D. Gingival Inflammation

E. Bleeding

Basically SCURVY.



2. Sugar alcohols (Polyols) are Sorbitol and Galactitol.

Sorbitol derived from sugar is osmotically active and is responsible for damage to:

A. The lens (Cataract formation)

B. Schwann cells (Peripheral neuropathy)

C. Pericytes (Retinopathy)

All those associated with Diabetes Mellitus.



Galactitol derived from galactose and contributes to cataract formation in galactosemia.




3. Glycosylation refers to the reaction of sugar aldehyde with protein amino groups to from a non-reversible covalent bond.

A. Excessive Glycosylation in diabetes leads to endothelial membrane alteration, producing microvascular disease.

B. In arterioles, Glycosylation of the basement membrane renders them permeable to protein, producing hyaline arteriolosclerosis.

[Doctor Ali]

Did you know?



Vitamin B12

Propionyl CoA

Methylmalonyl CoA

Methylmalonyl CoA mutase

Succinyl CoA

Methylmalonic acid




1. Propionyl CoA is converted to Methylmalonyl CoA

So basically it is this way:

Propionyl CoA → Methylmalonyl CoA


2. B12 is a cofactor for Methylmalonyl CoA mutase

So basically it’s going to be:

Methylmalonyl CoA + Methylmalonyl CoA mutase + B12 → Succinyl CoA (Citric acid cycle)


So the bottom of a line is very simple; you get the following equation:

Propionyl CoA → Methylmalonyl CoA + Methylmalonyl CoA mutase + B12 → Succinyl CoA (Citric acid cycle)



Now, what happens if there was Vitamin B12 deficiency?

Remember!! I said B12 is a cofactor. For what??? For Methylmalonyl CoA mutase. To do what??? To get Succinyl CoA. Now if there was B12 deficiency, do you think that you are going to get that Succinyl CoA?????


So then what happens??? I’m telling you what’s going to happen!!!!

1. Methylmalonyl CoA mutase needs B12 as a cofactor to produce Succinyl CoA.

2. Since B12 is deficit, Methylmalonyl CoA mutase is USELESSNESS.

3. When Methylmalonyl CoA mutase is USELESSNESS, there WILL be ACCUMULATION (Build up) of Methylmalonyl CoA.

4. Eventually this build up of Methylmalonyl CoA will automatically convert to increasing levels of Methylmalonic acid; which (Methylmalonic acid) will be detected in the urine. Why?

5. Because Methylmalonic acid is excreted in the urine; and increase Methylmalonic acid levels in the urine is indication of B12 deficiency.

6. Hey!!! That’s one way to find out if you’re B12 deficit!!!!!


Besides of accumulation of Methylmalonyl CoA, which is converted to Methylmalonic acid, which is excreted in the urine; what else happens in B12 deficit? Do you still remember that Propionyl CoA guy? Yeah. What it normally does?

Propionyl CoA → Methylmalonyl CoA


So what happens when there is Vitamin B12 deficiency?

1. Methylmalonyl CoA mutase is USELESSNESS → accumulation of Methylmalonyl CoA → which leads to increase Methylmalonic acid levels in the urine.

2. At the same time, there will be increase levels of Propionyl CoA


What’s the danger?

1. In the NORMAL PROCESS, acetyl CoA is use in MYELIN synthesis. For what? MYELINATION throughout your body where it is NEEDED; Brain, Spinal cord, and Peripheral nerves.

2. Propionyl CoA REPLACES acetyl CoA in myelin synthesis. And does what? DEMYELINATION of Spinal cord, Peripheral nerves and Brain.




Sound familiar to you guys? After all of this discussion, there should be one Neurological disease coming to your mind. Only one. Think about it. Only one Neurological disease should come to your mind.


I give a hit. B12 deficit and Demyelination. What comes in your mind? Well the answer is

SUBACUTE COMBINED DEGENERATION (VITAMIN B12 NEUROPATHY)!!!!


So!!! Before you go to bed tonight, make sure you take your B12. Trust me, it's good for you!!

[McNasty]

normal to high PCO2 in an asthmatic attack indicates respiratory fatigue and impending resp. collapse so intubation should be made ready

[Doctor Ali]

Did you know?



Saliva is characterized by:

1. High volume

2. Low concentrations of Na+ and Cl-

3. High concentrations of K+ and HCO3-

4. Hypotonicity

5. It is accurate when Saliva flow rate is LOW, not HIGH.




Pancreatic juice is characterized by:

1. High volume

2. Same Na+ and K+ concentrations as plasma

3. Much Higher HCO3- concentration

4. Much Lower Cl- concentration

5. Isotonicity

6. It is accurate when Pancreatic juice flow rate is HIGH, not LOW.

[Doctor Ali]

Did you know?



Slowly follow the arrows as if you are driving for the first time in a long trip. The arrows are your GPS system in which you need to follow in order for you to get your last stop.

[Doctor Ali]

Did you know?




1. Surcose is Table Sugar

Breaks down into Fructose and Glucose by an enzyme called Sucrase.



2. Lactose is Milk Sugar

Breaks down into Galactose and Glucose by an enzyme called Lactase.



3. Maltose is Starch Sugar

Breaks down into Glucose and Glucose by an enzyme called Maltase.