Pathophysiology | Wilkes University
1. In a first-degree atrioventricular (AV) block, which of the following best describes the ECG
findings?
A. Progressive lengthening of the PR interval until a QRS is dropped
B. A PR interval consistently greater than 0.20 seconds
C. Complete dissociation between P waves and QRS complexes
D. Occasional dropped QRS complexes without PR lengthening
Answer: B
Rationale: First-degree AV block is characterized by a delayed conduction through the AV
node, resulting in a PR interval longer than 200 milliseconds. Every atrial impulse is
eventually conducted to the ventricles, so there are no dropped beats. This condition is
often benign and can be found in healthy individuals or as a result of medication side
effects.
2. Which valvular disorder is most likely to result in left atrial enlargement and pulmonary
venous congestion?
A. Aortic Stenosis
B. Tricuspid Regurgitation
C. Mitral Stenosis
,D. Pulmonic Regurgitation
Answer: C
Rationale: Mitral stenosis involves a narrowing of the mitral valve, which obstructs blood
flow from the left atrium into the left ventricle. This obstruction causes a pressure backup
into the left atrium, leading to its dilation and increased pressure in the pulmonary veins.
Over time, this leads to pulmonary edema and right-sided heart strain.
3. A patient is diagnosed with a massive pulmonary embolism (PE). What is the primary
pathophysiological consequence leading to sudden death?
A. Left ventricular hypertrophy
B. Systemic hypertension
C. Increased pulmonary compliance
D. Acute right ventricular failure
Answer: D
Rationale: A massive pulmonary embolism causes a sudden and dramatic increase in
pulmonary vascular resistance. This acute increase in afterload overwhelms the right
ventricle, leading to acute right-sided heart failure and cardiogenic shock. Without
immediate intervention, the decrease in left-sided preload results in systemic hypotension
and death.
4. What is the hallmark of the late-phase response in asthma pathophysiology?
A. Eosinophil recruitment and airway inflammation
, B. Immediate bronchospasm mediated by histamine
C. Rapid resolution of symptoms without treatment
D. Decreased mucus production
Answer: A
Rationale: The late-phase response in asthma occurs 4 to 8 hours after the initial trigger
and is characterized by the recruitment of inflammatory cells like eosinophils and
neutrophils. These cells release mediators that cause further epithelial damage and edema.
This phase is responsible for the prolonged airway hyperresponsiveness seen in asthmatic
patients.
5. In emphysema, the destruction of alveolar walls is primarily caused by an imbalance
between:
A. Insulin and glucagon
B. Sodium and potassium
C. Proteases and antiproteases
D. Sympathetic and parasympathetic tone
Answer: C
Rationale: Emphysema results from an imbalance where protease enzymes, like elastase,
break down the structural proteins of the lung. Normally, antiproteases like alpha-1