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

1. Introduction to Anatomy & Physiology

Introduction to Organ Systems

Anatomy & Physiology

1. Introduction to Anatomy & Physiology

Introduction to Organ Systems

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Multiple Choice

During the compression stroke of the cardiac cycle, which heart valves are open?

Semilunar valves

Both AV and semilunar valves

Atrioventricular (AV) valves

Neither AV nor semilunar valves

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Verified step by step guidance

Understand the cardiac cycle: The compression stroke refers to ventricular systole, where the ventricles contract to pump blood out of the heart.

Recall the function of the heart valves: Atrioventricular (AV) valves prevent backflow into the atria, while semilunar valves prevent backflow into the ventricles.

During ventricular systole, the AV valves (tricuspid and mitral) are closed to prevent blood from flowing back into the atria.

The semilunar valves (pulmonary and aortic) are also closed during the compression stroke because the pressure in the ventricles is building up but has not yet exceeded the pressure in the arteries to open these valves.

Conclude that during the compression stroke, neither the AV valves nor the semilunar valves are open, as the heart is preparing to eject blood but has not yet done so.