ACSM-EP Cardiovascular Physiology 4 — Questions and Answers
Question 1: Which baroreceptors are the PRIMARY sensors for detecting acute changes in arterial blood pressure?
- Chemoreceptors in the medulla
- Stretch receptors in the carotid sinus and aortic arch (Correct answer)
- Volume receptors in the right atrium
- J-receptors in pulmonary capillaries
Correct answer: Stretch receptors in the carotid sinus and aortic arch
High-pressure baroreceptors located in the carotid sinus and aortic arch detect arterial wall stretch and provide rapid reflex feedback to regulate blood pressure.
Question 2: What physiological mechanism explains why heart rate does not increase linearly with cardiac output during very high-intensity exercise?
- Stroke volume increases dramatically at high intensities
- Vagal rebound limits maximum heart rate
- Stroke volume plateaus and cardiac output becomes heart-rate dependent (Correct answer)
- Peripheral vasoconstriction reduces venous return
Correct answer: Stroke volume plateaus and cardiac output becomes heart-rate dependent
At higher exercise intensities, stroke volume plateaus (limited filling time) and further increases in cardiac output rely primarily on increasing heart rate.
Question 3: Which Fick equation component is most responsible for the higher VO₂max observed in elite endurance athletes compared to sedentary individuals?
- Higher maximal heart rate
- Greater maximal cardiac output (Q̇max) (Correct answer)
- Lower arterial oxygen content
- Reduced mitochondrial density
Correct answer: Greater maximal cardiac output (Q̇max)
Elite endurance athletes primarily achieve higher VO₂max through substantially greater maximal cardiac output, facilitated by larger stroke volumes from cardiac hypertrophy and increased plasma volume.
Question 4: A client exhibits a blunted heart rate response to increasing exercise intensity. Which condition is MOST likely responsible?
- Mitral valve prolapse
- Chronotropic incompetence (Correct answer)
- Isolated systolic hypertension
- Anemia
Correct answer: Chronotropic incompetence
Chronotropic incompetence is defined as an inability to appropriately increase heart rate in response to increasing metabolic demand, often seen in heart failure or following cardiac surgery.
Question 5: During recovery from maximal exercise, which cardiovascular variable returns to resting values MOST rapidly?
- Plasma volume
- Heart rate (Correct answer)
- Systolic blood pressure
- Stroke volume
Correct answer: Heart rate
Heart rate declines rapidly post-exercise (within 1–2 minutes) due to rapid vagal reactivation, while stroke volume, blood pressure, and plasma volume take longer to normalize.
Question 6: Which vascular adaptation occurs with long-term aerobic exercise training?
- Decreased capillary density in skeletal muscle
- Increased arterial stiffness
- Reduced resting systolic blood pressure in hypertensive individuals (Correct answer)
- Elevated resting peripheral vascular resistance
Correct answer: Reduced resting systolic blood pressure in hypertensive individuals
Regular aerobic training reduces resting systolic blood pressure by approximately 5–7 mmHg in hypertensive individuals through improved vascular compliance and reduced sympathetic tone.
Question 7: Which cardiac chamber generates the highest pressure during systole?
- Right atrium
- Left atrium
- Right ventricle
- Left ventricle (Correct answer)
Correct answer: Left ventricle
The left ventricle generates systolic pressures of approximately 120 mmHg to overcome systemic vascular resistance, compared to ~25 mmHg in the right ventricle.
ACSM-EP Cardiovascular Physiology 4
Which baroreceptors are the PRIMARY sensors for detecting acute changes in arterial blood pressure?