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

16. The Endocrine System

Introduction to the Endocrine System

Anatomy & Physiology

16. The Endocrine System

Introduction to the Endocrine System

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Multiple Choice

Which hormone increases blood calcium levels when it is secreted?

Calcitonin

Insulin

Aldosterone

Parathyroid hormone (PTH)

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Verified step by step guidance

Step 1: Understand the role of calcium in the body. Calcium is essential for various physiological processes, including muscle contraction, nerve signaling, and blood clotting. The body tightly regulates blood calcium levels to maintain homeostasis.

Step 2: Identify the hormones involved in calcium regulation. The key hormones are Parathyroid Hormone (PTH), Calcitonin, and Vitamin D. PTH increases blood calcium levels, Calcitonin decreases blood calcium levels, and Vitamin D aids in calcium absorption from the intestines.

Step 3: Learn the mechanism of Parathyroid Hormone (PTH). PTH is secreted by the parathyroid glands in response to low blood calcium levels. It acts on three main targets: bones (stimulates osteoclasts to release calcium into the blood), kidneys (reduces calcium excretion and increases phosphate excretion), and intestines (indirectly increases calcium absorption by activating Vitamin D).

Step 4: Compare PTH with Calcitonin. Calcitonin, secreted by the thyroid gland, has the opposite effect of PTH. It lowers blood calcium levels by inhibiting osteoclast activity and promoting calcium storage in bones. This distinction helps clarify why PTH increases blood calcium levels.

Step 5: Eliminate the incorrect options. Insulin regulates blood glucose levels, not calcium. Aldosterone regulates sodium and potassium balance, not calcium. Calcitonin decreases blood calcium levels, making Parathyroid Hormone (PTH) the correct answer.