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

Electrical Conduction System of the Heart

Anatomy & Physiology

18. The Heart

Electrical Conduction System of the Heart

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Problem 10

Textbook Question

The ______ is the primary pacemaker of the heart.
a. Atrioventricular node
b. sinoatrial node
c. Purkinje fiber system
d. Atrioventricular bundle

Verified step by step guidance

Step 1: Understand the role of the pacemaker in the heart. The pacemaker is responsible for initiating and regulating the electrical impulses that control the heartbeat.

Step 2: Review the anatomy of the heart's conduction system. The conduction system includes the sinoatrial (SA) node, atrioventricular (AV) node, atrioventricular bundle, and Purkinje fibers.

Step 3: Learn the specific function of each component. The sinoatrial (SA) node is located in the right atrium and is known as the primary pacemaker because it generates the initial electrical impulse that sets the heart rate. The atrioventricular (AV) node acts as a secondary pacemaker and delays the impulse to allow the ventricles to fill. The atrioventricular bundle and Purkinje fibers help propagate the impulse through the ventricles.

Step 4: Compare the options provided in the question. The sinoatrial (SA) node is the correct answer because it is the primary pacemaker of the heart, while the other components play supporting roles in the conduction system.

Step 5: Confirm your understanding by visualizing the pathway of electrical conduction in the heart, starting from the sinoatrial (SA) node and moving through the atrioventricular (AV) node, atrioventricular bundle, and Purkinje fibers.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Sinoatrial Node

The sinoatrial (SA) node is a specialized group of cells located in the right atrium of the heart. It is known as the primary pacemaker because it generates electrical impulses that initiate the heartbeat, setting the rhythm for the entire heart. The SA node's activity is influenced by the autonomic nervous system, which adjusts heart rate based on the body's needs.

Atrioventricular Node

The atrioventricular (AV) node is another critical component of the heart's electrical conduction system, located between the atria and ventricles. It serves as a gatekeeper, receiving impulses from the SA node and delaying them slightly before passing them to the ventricles. This delay allows the atria to contract and fill the ventricles with blood before they contract, ensuring efficient blood flow.

Electrical Conduction System

The electrical conduction system of the heart includes structures such as the SA node, AV node, bundle of His, and Purkinje fibers. This system coordinates the heart's contractions by transmitting electrical signals throughout the heart muscle. Understanding this system is essential for comprehending how the heart maintains a regular rhythm and responds to physiological demands.

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