Random USMLE Facts volume 10-5

Rahul's Noteblog Notes on USMLE facts, Exam Tips, and USMLE Lab Values Random USMLE Facts volume 10-5

Random USMLE Facts volume 10-5:

USMLE Facts 1	USMLE Facts 2	USMLE Facts 3	USMLE Facts 4	USMLE Facts 5
USMLE Facts 6	USMLE Facts 7	USMLE Facts 8	USMLE Facts 9	USMLE Facts 10

What are some ECG findings in first-degree AV block?

Increased PR interval without missed QRS complexes.

What are some ECG findings in SA exit block?

Skipped beats.

What are some ECG findings in type I second-degree AV block?

Progressive prolongation of PR interval until there is a P-wave conduction failure.

What are some ECG findings in type II second-degree AV block?

Non-conducted P waves, ie., no QRS following P waves. Normal PR interval.

What are some ECG findings in third-degree AV block?

No relation between P and QRS complexes.

What part of the lung does active TB affect?

Apex.

What parts of the lungs does latent TB affect?

Middle lobe.

What are the findings in elbow dislocation?

There is posterior displacement of the ulna and anterior displacement of the humerus. The ulnar and median nerves are damaged, and the brachial artery is damaged; the affected individual would experience weak wrist flexion, loss of abduction, and adduction of the digits, loss of hypothenar muscles, and lumbricals 3 and 4, and weakened flexion of 4th and 5th digit.

The efficacy of antipsychotic agents is related to their what ability?

Dopamine (D2) blocking ability. Blockade of D2 receptors causes increased cAMP levels.

What is a paradoxical movement?

A paradoxical movement occurs when a portion of the apex of the left ventricle budges outward during systole and inward during diastole. This occurs due to infarction of the left anterior descending artery.

What disorder results in the immune-mediated destruction of platelets by the spleen?

Idiopathic thrombocytopenic purpura. A peripheral smear shows only a few large, young platelets; affected individual may experience easy bruising.

Cannon a Wave ECG:

What is going on in the above ECG at "B?"

This is a "cannon A wave" due to premature contraction of the ventricle associated with B before the P wave could cause atrial contraction. The mean left atrial pressure is very high.

For an autosomal recessive disease, the frequency of heterozygote carries of a disease in a population is 0.1; what is the probability that two individuais from this community produce an affected child?

Individual probabilities x probability that the child is a homozygote = 0.1 x 0.1 x (1/4) = 0.0025.

Hemolytic anemia is associated with what genetic defect?

Defects in glycolysis or hexose monophosphate shunt (pentose phosphate pathway). An important enzyme of these pathways is pyruvate kinase. Pyruvate kinase deficiency is an autosomal recessive disorder.

Where are all the RNA polymerases located?

Within the nucleus; except RNA pol I which is located in the nucleolus.

USMLE Facts 1	USMLE Facts 2	USMLE Facts 3	USMLE Facts 4	USMLE Facts 5
USMLE Facts 6	USMLE Facts 7	USMLE Facts 8	USMLE Facts 9	USMLE Facts 10

Additional Readings: