Which of the following statements is false?

a. The sympathetic nervous system releases epinephrine and norepinephrine, which are positive chronotropic and inotropic agents.

b. The endocrine system regulates cardiac output through chronotropic and inotropic hormones and through hormones that regulate water balance.

c. The parasympathetic nervous system releases acetylcholine and epinephrine, which are strongly negative inotropic agents.

d. Factors such as electrolyte concentrations, body temperature, and age all affect cardiac output.

Video transcript

Hi, everyone. Let's take a look at this practice problem together, abnormal levels of electrolytes, especially potassium can affect the electrical conduction system of the heart and lead to bradycardia. How does bradycardia impact the cardiac process? The answer options are a, it increases heart preload. B it decreases heart rate. C it increases cardiac output and D it can reduce blood volume. Well, what is bradycardia? It is abnormally slow heart rate. So how does a slow heart rate affect cardiac functioning? Option? A it increases heart preload. Recall that preload is the stretching and ventricular muscle cells after ventricular feeling and preload is proportional to blood volume in the ventricles at the end of diastole increases in heart preload depends on venous return and ventricular filling. It does not depend on the rate of the heartbeat. So option A is incorrect. Option C it increases cardiac output. Recall that cardiac output can be calculated by multiplying the heart rate times the stroke volume. So if the heart rate is decreased, which is what's happening in bradycardia, this will also cause overall decrease in cardiac output. So option C is incorrect. Option D it can reduce blood volume. So heart rate does not affect blood volume or production of blood. So, option D is incorrect since bradycardia is the abnormal slow heart rate. The correct answer is option B it decreases heart rate. All right, everyone. I hope you found this helpful and I'll see you soon for the next practice problem.