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

During the isovolumetric relaxation phase of the cardiac cycle, which of the following occurs?

The atrioventricular valves are open and blood flows into the ventricles.

The semilunar valves are open and blood is ejected from the ventricles.

All heart valves are closed and ventricular pressure is decreasing.

Ventricular pressure is increasing as the ventricles contract.

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Verified step by step guidance

Understand the cardiac cycle phases: The cardiac cycle consists of systole (contraction) and diastole (relaxation). Isovolumetric relaxation occurs during early diastole, right after ventricular systole.

Define isovolumetric relaxation: During this phase, the ventricles are relaxing, but the volume of blood within them remains constant because all heart valves are closed.

Analyze the pressure changes: As the ventricles relax, the pressure inside them decreases. This is a key characteristic of the isovolumetric relaxation phase.

Evaluate the state of the valves: During isovolumetric relaxation, both the atrioventricular (AV) valves and semilunar valves are closed. This prevents blood flow into or out of the ventricles during this phase.

Confirm the correct description: Based on the above analysis, the correct description of the isovolumetric relaxation phase is 'All heart valves are closed and ventricular pressure is decreasing.'