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

26. Fluid and Electrolyte Balance, Acid Base Balance

Acid-Base Balance

Anatomy & Physiology

26. Fluid and Electrolyte Balance, Acid Base Balance

Acid-Base Balance

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Problem 19

Textbook Question

What are the three major buffer systems in body fluids? How does each system work?

Verified step by step guidance

Identify the three major buffer systems in body fluids: the bicarbonate buffer system, the phosphate buffer system, and the protein buffer system.

Explain the bicarbonate buffer system: This system primarily operates in the blood and extracellular fluid. It involves the equilibrium between carbonic acid (H₂CO₃) and bicarbonate ions (HCO₃⁻). When the pH decreases (becomes more acidic), bicarbonate ions react with hydrogen ions (H⁺) to form carbonic acid, reducing acidity. Conversely, when the pH increases (becomes more basic), carbonic acid dissociates into bicarbonate ions and hydrogen ions, lowering the pH.

Describe the phosphate buffer system: This system is more active in intracellular fluids and the kidneys. It involves the equilibrium between dihydrogen phosphate (H₂PO₄⁻) and hydrogen phosphate (HPO₄²⁻). When the pH decreases, hydrogen phosphate binds with hydrogen ions to form dihydrogen phosphate, reducing acidity. When the pH increases, dihydrogen phosphate releases hydrogen ions, lowering the pH.

Discuss the protein buffer system: Proteins, especially hemoglobin in red blood cells, act as buffers due to their amino acid residues. The amino groups (-NH₂) can bind to hydrogen ions when the pH decreases, while the carboxyl groups (-COOH) can release hydrogen ions when the pH increases. This helps stabilize pH in both intracellular and extracellular fluids.

Summarize how these systems work together: The buffer systems interact to maintain the body's pH within a narrow range (approximately 7.35-7.45). They respond to changes in hydrogen ion concentration to prevent significant fluctuations in pH, ensuring proper cellular function and homeostasis.

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Key Concepts

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

Bicarbonate Buffer System

The bicarbonate buffer system is the primary buffer in extracellular fluid, maintaining pH balance by using bicarbonate ions (HCO3-) and carbonic acid (H2CO3). When pH decreases, bicarbonate can neutralize excess hydrogen ions (H+), while an increase in pH can convert bicarbonate to carbonic acid, releasing H+ to lower pH. This system is crucial for regulating blood pH and is influenced by respiratory and renal functions.

Phosphate Buffer System

The phosphate buffer system operates mainly in intracellular fluid and the kidneys, utilizing dihydrogen phosphate (H2PO4-) and hydrogen phosphate (HPO4^2-) to stabilize pH. When pH drops, HPO4^2- can accept H+ to form H2PO4-, while an increase in pH allows H2PO4- to release H+, thus lowering pH. This system is particularly important in buffering urine and cellular environments.

Protein Buffer System

The protein buffer system relies on the amino acids in proteins, which can act as both acids and bases due to their side chains. Proteins can accept H+ when pH decreases, or release H+ when pH increases, thus helping to maintain a stable pH in body fluids. Hemoglobin in red blood cells is a key example, as it binds to H+ and CO2, playing a vital role in blood pH regulation during respiration.