A woman with coronary artery disease is starting to go for a walk. As she begins, her heart rate accelerates from a resting pulse of 60 bpm until it reaches a rate of 120 bpm, at which point she begins to feel a tightening in her chest. She stops walking to rest and the tightening resolves. This has been happening to her consistently for the last 6 months. Which of the following is a true statement?
AThis patient's chest pain is indicative of transmural ischemia
BPerfusion of the myocardium takes place equally throughout the cardiac cycle
CIncreasing the heart rate increases the amount of time spent during each cardiac cycle
DIncreasing the heart rate decreases the relative amount of time spent during diastole
EPerfusion of the myocardium takes place primarily during systole
A 37-year-old man is brought to the emergency department by ambulance after a motor vehicle accident. He suffered multiple deep lacerations and experienced significant blood loss during transport. In the emergency department, his temperature is 98.6°F (37°C), blood pressure is 102/68 mmHg, pulse is 112/min, and respirations are 22/min. His lacerations are sutured and he is given 2 liters of saline by large bore intravenous lines. Which of the following changes will occur in this patient's cardiac physiology due to this intervention?
AIncreased cardiac output and unchanged right atrial pressure
BDecreased cardiac output and increased right atrial pressure
CIncreased cardiac output and decreased right atrial pressure
DIncreased cardiac output and increased right atrial pressure
EDecreased cardiac output and decreased right atrial pressure
Which factor most strongly influences coronary blood flow during exercise?
AEndothelin release
BMetabolic demand
CMyogenic response
DNeural regulation
EBaroreceptor reflex
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