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

1. Introduction to Anatomy & Physiology

Introduction to Organ Systems

Anatomy & Physiology

1. Introduction to Anatomy & Physiology

Introduction to Organ Systems

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Multiple Choice

Functionally, troponin provides a binding site for which ions?

Magnesium

Potassium

Calcium

Sodium

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Verified step by step guidance

Understand the role of troponin in muscle contraction: Troponin is a regulatory protein complex found in skeletal and cardiac muscle fibers. It plays a critical role in the contraction process by interacting with calcium ions.

Recall the mechanism of muscle contraction: When a muscle fiber is stimulated, calcium ions are released from the sarcoplasmic reticulum into the cytoplasm. These ions bind to troponin, causing a conformational change.

Identify the specific ion that binds to troponin: Calcium ions (Ca²⁺) are the ones that bind to troponin, specifically to the troponin C subunit, initiating the contraction process.

Understand the result of calcium binding: When calcium binds to troponin, it causes a shift in the position of tropomyosin, exposing the binding sites on actin filaments for myosin heads, which leads to muscle contraction.

Review why other ions are not correct: Magnesium (Mg²⁺), Potassium (K⁺), and Sodium (Na⁺) have different roles in cellular processes, such as maintaining membrane potential or acting as cofactors, but they do not bind to troponin to initiate muscle contraction.