American Board of Surgery Qualifying Exam (ABS QE) Practice Test

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Prepare for the ABS QE with flashcards and multiple-choice questions. Each question provides hints and explanations to enhance understanding. Start your journey to becoming a certified surgeon and tackle your exam with confidence!

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Beta-1 receptors are primarily associated with which cardiac function?

Decreased myocardial contraction
Increased heart rate
Relaxation of smooth muscle
Vasoconstriction

The correct answer is: Increased heart rate

Beta-1 receptors are a type of adrenergic receptor primarily found in the heart. When stimulated, they play a crucial role in regulating cardiac function. One of the key effects of Beta-1 receptor activation is an increase in heart rate, a phenomenon known as positive chronotropic effect. This results from their role in enhancing the rate of depolarization in the sinoatrial (SA) node, which is responsible for initiating the heartbeat. Additionally, the activation of Beta-1 receptors also enhances myocardial contractility, known as positive inotropic effect, leading to stronger heart contractions. While smooth muscle relaxation and vasoconstriction involve other receptor types, such as Beta-2 or alpha receptors, Beta-1 receptors specifically focus their action on cardiac tissues, making increased heart rate the direct and most relevant response associated with their activation.