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

Sliding Filament Theory and the Sacromere

Anatomy & Physiology

9. Muscle Tissue

Sliding Filament Theory and the Sacromere

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3:13 minutes

Problem 17

Textbook Question

What is the calcium-binding protein in smooth muscle tissue?

Verified step by step guidance

Understand that smooth muscle tissue is a type of muscle found in the walls of hollow organs, such as the intestines, blood vessels, and bladder, and it contracts involuntarily.

Recall that calcium plays a critical role in muscle contraction by binding to specific proteins that regulate the contraction process.

Learn that in smooth muscle tissue, the calcium-binding protein responsible for initiating contraction is calmodulin, which differs from the troponin complex found in skeletal and cardiac muscle.

Recognize that calmodulin binds calcium ions (Ca²⁺) when intracellular calcium levels rise, forming a calcium-calmodulin complex.

Understand that the calcium-calmodulin complex activates myosin light chain kinase (MLCK), which phosphorylates myosin heads, enabling them to interact with actin filaments and produce contraction.

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Key Concepts

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

Calcium-Binding Proteins

Calcium-binding proteins are proteins that can bind calcium ions, playing a crucial role in various cellular processes. In smooth muscle tissue, these proteins facilitate the contraction and relaxation of muscle fibers by regulating calcium levels, which are essential for muscle function.

Smooth Muscle Tissue

Smooth muscle tissue is a type of involuntary muscle found in various organs, including the intestines and blood vessels. Unlike skeletal muscle, smooth muscle is not striated and is controlled by the autonomic nervous system, allowing for involuntary movements such as peristalsis and vasodilation.

Calmodulin

Calmodulin is a specific calcium-binding protein that plays a pivotal role in smooth muscle contraction. When calcium ions bind to calmodulin, it undergoes a conformational change that activates various enzymes and proteins, leading to the phosphorylation of myosin light chains, which is essential for muscle contraction.

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6:26m