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 two hormones, produced by the thyroid and parathyroid glands, have antagonistic effects on blood calcium levels?

Insulin and glucagon

Thyroxine and triiodothyronine

Calcitonin and parathyroid hormone (PTH)

Aldosterone and cortisol

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Verified step by step guidance

Step 1: Understand the role of the thyroid and parathyroid glands in regulating blood calcium levels. The thyroid gland produces calcitonin, which lowers blood calcium levels, while the parathyroid glands produce parathyroid hormone (PTH), which increases blood calcium levels.

Step 2: Learn the mechanism of calcitonin. Calcitonin reduces blood calcium levels by inhibiting osteoclast activity (cells that break down bone tissue) and promoting calcium deposition in bones. It also decreases calcium absorption in the intestines and increases calcium excretion in the kidneys.

Step 3: Learn the mechanism of parathyroid hormone (PTH). PTH increases blood calcium levels by stimulating osteoclast activity to release calcium from bones, enhancing calcium absorption in the intestines (via activation of vitamin D), and reducing calcium excretion in the kidneys.

Step 4: Recognize the antagonistic relationship between calcitonin and PTH. Calcitonin and PTH work in opposition to maintain calcium homeostasis in the blood. When blood calcium levels are high, calcitonin is released to lower them. When blood calcium levels are low, PTH is released to raise them.

Step 5: Eliminate incorrect options based on their functions. Insulin and glucagon regulate blood glucose, not calcium. Thyroxine and triiodothyronine are thyroid hormones involved in metabolism. Aldosterone and cortisol are adrenal hormones involved in fluid balance and stress response, respectively. The correct answer is calcitonin and parathyroid hormone (PTH).