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

Which of the following statements about the cardiac cycle is true?

The cardiac cycle is regulated solely by the autonomic nervous system.

The cardiac cycle includes both systole and diastole phases.

The cardiac cycle consists of a single phase of ventricular contraction.

The cardiac cycle is initiated by the closing of the semilunar valves.

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Verified step by step guidance

Understand the cardiac cycle: The cardiac cycle refers to the sequence of events that occur in the heart during one complete heartbeat. It includes both systole (contraction) and diastole (relaxation) phases.

Identify the phases: Systole is when the heart muscle contracts and pumps blood from the chambers into the arteries. Diastole is when the heart muscle relaxes and allows the chambers to fill with blood.

Consider the role of the autonomic nervous system: While the autonomic nervous system influences the heart rate and strength of contraction, it does not solely regulate the cardiac cycle. The heart has its own intrinsic conduction system.

Evaluate the statement about ventricular contraction: The cardiac cycle does not consist of a single phase of ventricular contraction. It involves both contraction and relaxation phases.

Analyze the initiation of the cardiac cycle: The cardiac cycle is initiated by the sinoatrial (SA) node, not by the closing of the semilunar valves. The closing of the semilunar valves occurs at the end of systole.