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

Electrocardiogram (ECG)

Anatomy & Physiology

18. The Heart

Electrocardiogram (ECG)

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Multiple Choice

What does the QRS wave on an electrocardiogram (ECG) indicate is happening in the heart?

Ventricular depolarization

Atrial repolarization

Ventricular repolarization

Atrial depolarization

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Verified step by step guidance

Understand the components of an electrocardiogram (ECG): An ECG is a graphical representation of the electrical activity of the heart. It consists of several waves, including the P wave, QRS complex, and T wave.

Identify the QRS complex: The QRS complex is a specific part of the ECG that represents a particular phase of the cardiac cycle. It is typically the most prominent feature on the ECG trace.

Recognize the physiological process: The QRS complex corresponds to the depolarization of the ventricles. Depolarization is the process by which cardiac muscle cells change their electrical charge, leading to muscle contraction.

Differentiate from other waves: The P wave represents atrial depolarization, while the T wave represents ventricular repolarization. Atrial repolarization occurs during the QRS complex but is obscured by the larger ventricular depolarization signal.

Conclude the function of the QRS complex: Based on the understanding of the ECG components, the QRS wave specifically indicates ventricular depolarization, which is the electrical activity that triggers the contraction of the ventricles.