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 Heart2h 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 which following phase (or phases) of the cardiac cycle is the blood volume in the ventricles constant?

Isovolumetric contraction.

Isovolumetric relaxation.

Ventricular ejection.

A & B are correct.

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Verified step by step guidance

Understand the cardiac cycle: The cardiac cycle consists of several phases, including isovolumetric contraction, ventricular ejection, and isovolumetric relaxation.

Define isovolumetric contraction: This phase occurs after the atrioventricular (AV) valves close and before the semilunar valves open. During this time, the ventricles contract but the volume of blood remains constant because all valves are closed.

Define isovolumetric relaxation: This phase occurs after the semilunar valves close and before the AV valves open. The ventricles relax, but the blood volume remains constant as all valves are closed.

Define ventricular ejection: This phase occurs when the semilunar valves open, allowing blood to be ejected from the ventricles into the arteries. During this phase, the blood volume in the ventricles decreases.

Conclude which phases have constant blood volume: Since both isovolumetric contraction and isovolumetric relaxation involve closed valves and no change in blood volume, these are the phases where the blood volume in the ventricles remains constant.