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

Electrical Conduction System of the Heart

Anatomy & Physiology

18. The Heart

Electrical Conduction System of the Heart

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Multiple Choice

Which of the following factors gives the myocardium its high resistance to fatigue?

gap junctions

the presence of intercalated discs

a very large number of mitochondria in the cytoplasm

the coronary circulation

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Verified step by step guidance

Understand the function of the myocardium: The myocardium is the muscular tissue of the heart responsible for pumping blood throughout the body. It requires a continuous supply of energy to function effectively without fatigue.

Identify the role of mitochondria: Mitochondria are organelles within cells that produce ATP (adenosine triphosphate), the energy currency of the cell, through cellular respiration. A high number of mitochondria means more ATP can be produced, providing sustained energy for muscle contraction.

Consider the importance of energy supply: The heart muscle needs a constant and efficient energy supply to maintain its continuous contractions. A large number of mitochondria ensures that the myocardium has a high capacity for aerobic respiration, which is crucial for endurance and resistance to fatigue.

Evaluate other factors: While gap junctions and intercalated discs are important for the synchronized contraction and communication between cardiac cells, they do not directly contribute to resistance to fatigue. Coronary circulation provides oxygen and nutrients but does not directly increase resistance to fatigue.

Conclude the reasoning: The presence of a very large number of mitochondria in the cytoplasm of myocardial cells is the key factor that gives the myocardium its high resistance to fatigue, as it ensures a robust and continuous supply of energy.