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

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Multiple Choice

An increase in stroke volume is a result of which of the following?

increased afterload

increased venous return

decreased preload

decreased contractility

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Verified step by step guidance

Understand the concept of stroke volume: Stroke volume is the amount of blood ejected by the left ventricle during each contraction. It is influenced by three main factors: preload, afterload, and contractility.

Define preload: Preload refers to the degree of stretch in the ventricular walls before contraction, which is directly related to venous return. Increased venous return leads to greater preload, enhancing stroke volume through the Frank-Starling mechanism.

Define afterload: Afterload is the resistance the heart must overcome to eject blood. Increased afterload typically reduces stroke volume because the heart has to work harder to pump blood against higher resistance.

Define contractility: Contractility refers to the strength of the heart's contraction. Increased contractility enhances stroke volume by enabling the heart to pump more blood per beat.

Analyze the options: Increased venous return increases preload, which boosts stroke volume. Decreased preload and decreased contractility would lower stroke volume, while increased afterload would also reduce stroke volume. Therefore, the correct answer is 'increased venous return.'