A 50-year-old female presents with a low heart rate and low blood pressure. She is given an IV infusion of fluids. The increase in atrial distension results in:
A) renal retention of fluids.
B) depressed myocardial contractility.
C) release of acetylcholine.
D) increased heart rate.

Question

Quizplus · Accepted Answer

The increase in atrial distension activates baroreceptors in the atria which sends a signal to the medulla oblongata to decrease sympathetic outflow and increase parasympathetic outflow. This results in a decrease in heart rate and BP. However, the increase in parasympathetic outflow also causes the release of acetylcholine which increases the heart rate. Therefore, the best choice is D, as the increase in atrial distension would most likely lead to an increased heart rate due to the release of acetylcholine.

A 50-Year-Old Female Presents with a Low Heart Rate and Low