Heart Sounds Tutorial

Another free site with wonderful examples of various normal and abnormal heart sounds with matching physiological explanations. The animations are basic but clear. There is also a testing mode to make sure that you got it. Good revision for Year 3 to 5 students.

A Court Case

No, don't worry, I have not been taken to jail. Take a look here though and you will find a tongue in cheek argument between the sympathetic and parasympathetic systems. Rather fun way to learn. Enjoy!

Physiology Question Explanation

Only one of you attempted this question, which actually is extremely important. Hence it's worth re-stating together with the explanation for all you clinical students out there.

A 26-year-old man is admitted through the emergency department to the hospital for a heroin overdose. His heart rate is 45 beats/min, and his blood pressure is 75/40 mm Hg. Which of the following best depicts the results from an arterial blood sample ?

pH PaCO2 (mm Hg) HCO3- (mEq/L)
A. 7.22 66 26
B. 7.34 29 15
C. 7.40 40 24
D. 7.47 20 14
E. 7.49 48 35

The correct answer is A.

This man has a respiratory acidosis. Overdose with drugs that suppress ventilation (e.g., heroin, morphine, barbiturates, methaqualone, and "sleeping pills") often causes hypercapnia. In patients with an intact renal response, the respiratory acidosis causes a compensatory rise in plasma HCO3-, which lessens the fall in pH. However, the renal response requires several days to develop fully. The plasma HCO3- of 26 mEq/L (normal: 22-28 mEq/L) for this man is typical of acute respiratory acidosis with little or no renal compensation.

Choice B reflects metabolic acidosis.

Choice C is normal.

Choice D reflects respiratory alkalosis.

Choice E reflects metabolic alkalosis.

Renal Physiology

Another FREE site developed by medical students which summarizes the important aspects of renal physiology. Covers:

· Renal Handling of Sodium and Potassium

· Urinary Concentration & Dilution

· Diuresis & Diuretics

· Acid-Base Balance

· Divalent Cations

Take the quiz at the end.

McGill University Virtual Stethoscope

This site provides a virtual stethoscope interface for auscultating normal and abnormal cardiac and respiratory sounds as well as other material related to auscultation and cardiac and pulmonary physiology and pathophysiology.

Useful for medical students from year 1 onwards.