9 USMLE Cardiology and Respiratory Basics Questions with Answers (Set 1)

These 9 quick USMLE cardiology and respiratory basics questions test the facts you must know cold: classic ECG patterns, aortic aneurysm rupture risk, coronary supply of the SA node and the cell types of the airways and alveoli. Each question includes the correct answer and an explanation.

Written by Dr. Ray Makar, MD, author of the Repeated USMLE Questions eBook series.

Prefer video? Watch daily USMLE case questions on MedFocus by Dr. Ray on YouTube.

How to use this page: read the question, pick your answer, then tap Show Answer and Explanation.

Questions

Question 1. Which of the following is the classic electrocardiogram (ECG) finding in atrial flutter?

A- Diffuse S-T segment elevation
B- Sawtooth P waves
C- S-T segment elevation in leads II. III and aVF
D- S-T segment elevation in anterior leads (V1-V4)

B- Sawtooth P waves- Atrial flutter shows regular sawtooth flutter waves, often with 2:1 block and a ventricular rate near 150/min.
The correct answer is B

 

Question 2. Which of the following is the classic electrocardiogram (ECG) finding in pericarditis?

A- Diffuse S-T segment elevation
B- Sawtooth P waves
C- S-T segment elevation in leads II. III and aVF
D- S-T segment elevation in anterior leads (V1-V4)

A- Diffuse S-T segment elevation- Acute pericarditis shows diffuse ST elevation with PR depression.
The correct answer is A

 

Question 3. Which of the following is the classic electrocardiogram (ECG) finding in inferior myocardial infarction (MI)?

A- Diffuse S-T segment elevation
B- Sawtooth P waves
C- S-T segment elevation in leads II. III and aVF
D- S-T segment elevation in anterior leads (V1-V4)

C- S-T segment elevation in leads II. III and aVF- Inferior MI shows ST elevation in leads II, III and aVF, usually from right coronary artery occlusion.
The correct answer is C

 

Question 4. Which of the following is the most important predictor of rupture of an abdominal aortic aneurysm?

A- Aneurysm diameter
B- Patient age
C- Hyperlipidemia
D- Family history

A- Aneurysm diameter- The risk of rupture rises sharply with size, especially above 5.5 cm, or with rapid growth (more than 0.5 cm in 6 months); these are indications for repair. Smoking and uncontrolled hypertension also increase the risk of expansion and rupture, and atherosclerosis is the main cause of abdominal aortic aneurysms.
The correct answer is A

 

Question 5. A 74-year-old man presents to the clinic with a complaint of palpitation and lightheadedness. Image studies revealed blockage of the artery to the SA node. This artery arises from which of these arteries?

A- Left coronary artery
B- Right coronary artery
C- Circumflex artery
D- Anterior interventricular artery
E- Posterior interventricular artery

The artery to the SA node is supplied by the right coronary artery.
The correct answer is B

 

Question 6. Which one of the following cells is derived from monocytes and lying within the alveoli?

A- Clara cells
B- K cells
C- Macrophages
D- Pneumocytes type I
E- Pneumocytes type II

C- Macrophages- Alveolar macrophages (dust cells) come from blood monocytes and clear particles from the alveoli.
The correct answer is C

 

Question 7. Which one of the following cells lines the alveoli and secretes the surfactant?

A- Clara cells
B- K cells
C- Macrophages
D- Pneumocytes type I
E- Pneumocytes type II

E- Pneumocytes type II- Type II pneumocytes secrete surfactant and regenerate type I pneumocytes after injury.
The correct answer is E

 

Question 8. Which one of the following cells is neuroendocrine and found within the epithelium of the bronchi?

A- Clara cells
B- K cells
C- Macrophages
D- Pneumocytes type I
E- Pneumocytes type II

B- K cells- K cells (Kulchitsky cells) are neuroendocrine cells of the bronchial epithelium and the origin of small cell carcinoma and carcinoid tumors.
The correct answer is B

 

Question 9. Which one of the following cells secretes glycosaminoglycans and found in the in the terminal and respiratory bronchioles?

A- Clara cells
B- K cells
C- Macrophages
D- Pneumocytes type I
E- Pneumocytes type II

A- Clara cells- Club (Clara) cells of the bronchioles secrete protective substances and act as stem cells for the bronchiolar epithelium.
The correct answer is A

 

High-yield points from this set

  • Sawtooth waves = atrial flutter; diffuse ST elevation = pericarditis; ST elevation in II, III, aVF = inferior MI.
  • AAA rupture risk depends mainly on diameter (repair at 5.5 cm or more).
  • The SA nodal artery usually comes from the right coronary artery.
  • Type II pneumocytes make surfactant; Kulchitsky cells give rise to small cell carcinoma.

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