Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

18. The Heart

Cardiac Cycle

Anatomy & Physiology

18. The Heart

Cardiac Cycle

Previous problemNext problem

Problem 18

Textbook Question

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

Step 1: Begin by understanding the key terms in the question. Chronotropic agents affect heart rate, while inotropic agents affect the strength of heart contractions. Positive chronotropic agents increase heart rate, and positive inotropic agents increase contraction strength. Negative agents have the opposite effects.

Step 2: Analyze statement (a). The sympathetic nervous system releases epinephrine and norepinephrine, which are known to be positive chronotropic and inotropic agents. This statement is true based on physiological principles.

Step 3: Evaluate statement (b). The endocrine system regulates cardiac output through hormones that influence heart rate (chronotropic effects), contraction strength (inotropic effects), and water balance (e.g., antidiuretic hormone). This statement is also true.

Step 4: Examine statement (c). The parasympathetic nervous system primarily releases acetylcholine, which has a negative chronotropic effect (slows heart rate). However, it does not release epinephrine, nor is acetylcholine a strongly negative inotropic agent. This statement is false.

Step 5: Review statement (d). Factors such as electrolyte concentrations (e.g., potassium and calcium), body temperature, and age are known to influence cardiac output. This statement is true. Therefore, the false statement is (c).

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Play a video:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

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, influenced by heart rate and stroke volume. Various factors, including hormonal regulation from the endocrine system, electrolyte balance, body temperature, and age, can affect cardiac output. Understanding these factors is crucial for assessing cardiovascular health and function.

Watch next

Master Systole, Diastole, Pressure, & Valves with a bite sized video explanation from Bruce Bryan

Start learning

Related Videos

Related Practice

Textbook Question

Which chamber generates the highest pressure during systole?

a. Right atrium

b. Right ventricle

c. Left atrium

d. Left ventricle

639

views

Textbook Question

The first heart sound is called ________ and it is caused by the closing of the ________ valves. It occurs at the beginning of the ________ phase of the cardiac cycle. The second heart sound is called ________ and it is caused by the closing of the ________ valves. It occurs at the beginning of the ________ phase of the cardiac cycle.

511

views

Textbook Question

Cardiac output is equal to:

a. End-diastolic volume minus end-systolic volume.

b. Heart rate multiplied by stroke volume.

c. Stroke volume divided by end-diastolic volume.

d. Heart rate multiplied by preload.

347

views

Textbook Question

An increase in preload causes a/an ________ in stroke volume in accordance with the ________ law. An increase in afterload causes a/an ________ in stroke volume. An increase in contractility causes a/an ________ in stroke volume.

431

views

Textbook Question

You are an athletic trainer who is working with someone planning to run a marathon. Your trainee tells you to give him a workout that will make his heart 'beat faster than ever before.' What do you tell him about the effects of too rapid a heart rate?

344

views

Multiple Choice

A doctor puts his stethoscope on a patient's chest over the location of the heart and hears an abnormal swishing sound. Which of the following conditions is the best diagnosis for the patient's condition?

890

views

Textbook Question

More than one choice may apply.

Given a volume of 150 ml at the end of diastole, a volume of 50 ml at the end of systole, and a heart rate of 60 bpm, the cardiac output is

a. 600 ml/min

b. 6 liters/min

c. 1200 ml/min