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

9. Muscle Tissue

Introduction to Muscles and Muscle Tissue

Anatomy & Physiology

9. Muscle Tissue

Introduction to Muscles and Muscle Tissue

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Multiple Choice

Select the description below that illustrates a difference between a sphincter and a circular muscle.

Circular muscles are only found in the heart, while sphincters are found in the digestive tract.

Both sphincter and circular muscles are always found in the limbs.

A sphincter muscle controls the opening and closing of a passageway, while a circular muscle does not necessarily regulate passageways.

Sphincter muscles are voluntary, whereas circular muscles are always involuntary.

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Verified step by step guidance

Step 1: Understand the definitions of sphincter muscles and circular muscles. Sphincter muscles are specialized circular muscles that control the opening and closing of passageways, such as the esophagus or anus. Circular muscles, on the other hand, are general muscles arranged in a circular pattern but do not necessarily regulate passageways.

Step 2: Analyze the options provided in the problem. Each option describes a potential difference between sphincter and circular muscles. Evaluate the accuracy of each statement based on anatomical and physiological knowledge.

Step 3: Eliminate incorrect options. For example, the statement 'Circular muscles are only found in the heart, while sphincters are found in the digestive tract' is incorrect because circular muscles are found in various locations, not just the heart. Similarly, 'Both sphincter and circular muscles are always found in the limbs' is incorrect because these muscles are not limited to the limbs.

Step 4: Focus on the correct statement. The correct answer is: 'A sphincter muscle controls the opening and closing of a passageway, while a circular muscle does not necessarily regulate passageways.' This accurately describes the functional difference between the two types of muscles.

Step 5: Clarify the voluntary vs. involuntary aspect. The statement 'Sphincter muscles are voluntary, whereas circular muscles are always involuntary' is not universally true. Some sphincter muscles, like the external anal sphincter, are voluntary, while others, like the lower esophageal sphincter, are involuntary. Circular muscles can also be involuntary depending on their location and function.