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.

Verified step by step guidance

1. Identify the key terms in each statement: sympathetic nervous system, parasympathetic nervous system, endocrine system, chronotropic and inotropic agents, cardiac output.
2. Understand the role of the sympathetic nervous system: it typically releases epinephrine and norepinephrine, which increase heart rate (positive chronotropic) and force of contraction (positive inotropic).
3. Examine the role of the parasympathetic nervous system: it primarily releases acetylcholine, which decreases heart rate (negative chronotropic) and has a minimal effect on contraction force (inotropic).
4. Review the endocrine system's influence on cardiac output: it involves hormones that can affect heart rate and contraction force, as well as hormones that regulate water balance, impacting blood volume and pressure.
5. Consider the factors affecting cardiac output: electrolyte concentrations, body temperature, and age can all influence heart function and output.

Key Concepts

Sympathetic Nervous System

The sympathetic nervous system is part of the autonomic nervous system that prepares the body for 'fight or flight' responses. It releases neurotransmitters like epinephrine and norepinephrine, which increase heart rate (positive chronotropic effect) and the force of heart contractions (positive inotropic effect), thereby enhancing cardiac output during stress or physical activity.

Parasympathetic Nervous System

The parasympathetic nervous system is the counterpart to the sympathetic system, promoting 'rest and digest' functions. It primarily uses acetylcholine as a neurotransmitter, which generally decreases heart rate (negative chronotropic effect) and can reduce the force of heart contractions (negative inotropic effect), counteracting the effects of the sympathetic nervous system.

Cardiac Output Regulation

Cardiac output is the volume of blood the heart pumps per minute and is influenced by various factors, including heart rate and stroke volume. It is regulated by the autonomic nervous system, hormones from the endocrine system, and physiological factors such as electrolyte levels, body temperature, and age, all of which can impact heart function and overall cardiovascular health.