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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

At what point in the cardiac cycle does the atrioventricular (AV) valve open?

During atrial systole

During ventricular systole

At the beginning of ventricular diastole

At the end of ventricular diastole

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Verified step by step guidance

Understand the cardiac cycle phases: The cardiac cycle consists of systole (contraction) and diastole (relaxation) for both atria and ventricles.

Identify the role of the atrioventricular (AV) valves: These valves separate the atria from the ventricles and prevent backflow of blood during ventricular contraction.

Recognize the timing of AV valve opening: The AV valves open when the pressure in the atria exceeds the pressure in the ventricles, allowing blood to flow from the atria to the ventricles.

Determine the phase when atrial pressure exceeds ventricular pressure: This occurs at the beginning of ventricular diastole, when the ventricles relax and their pressure drops.

Conclude that the AV valves open at the beginning of ventricular diastole, allowing blood to flow from the atria into the ventricles.