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 Action Potentials

Anatomy & Physiology

18. The Heart

Cardiac Action Potentials

Previous problemNext problem

Struggling with Anatomy & Physiology?

Join thousands of students who trust us to help them ace their exams!Watch the first video

Multiple Choice

Which of the following would increase cardiac output to the greatest extent?

Increased parasympathetic stimulation

Increased sympathetic nervous system activity

Decreased heart rate

Decreased venous return

Previous problemNext problem

Verified step by step guidance

Understand the concept of cardiac output (CO): Cardiac output is the amount of blood pumped by the heart per minute. It is calculated using the formula CO = HR × SV, where HR is heart rate and SV is stroke volume.

Analyze the role of the sympathetic nervous system: Increased sympathetic nervous system activity stimulates the heart to beat faster (increasing HR) and enhances the contractility of the heart muscle (increasing SV). Both factors contribute to a significant increase in cardiac output.

Evaluate parasympathetic stimulation: Increased parasympathetic stimulation generally decreases heart rate, which would lower cardiac output. This is the opposite of what is needed to increase cardiac output.

Consider the effect of decreased heart rate: A lower heart rate directly reduces cardiac output because it decreases the number of beats per minute, which reduces the volume of blood pumped by the heart.

Assess the impact of decreased venous return: Venous return is the amount of blood returning to the heart. A decrease in venous return reduces stroke volume, which in turn lowers cardiac output. This would not increase cardiac output to the greatest extent.