Ch. 2 The Chemistry of Life

Amerman3rd EditionHuman Anatomy & PhysiologyISBN: 9780138247201, 9780138247928, 9780138201814Not the one you use?Change textbook

Amerman 3rd Edition

Ch. 2 The Chemistry of Life

Problem L3.4

Chapter 2, Problem L3.4

Explain how buffer systems in the body work if the pH of body fluids increases. Is this an example of a negative or a positive feedback loop? Explain.

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Understand the concept of pH: pH is a measure of hydrogen ion (H⁺) concentration in a solution. A higher pH indicates a decrease in H⁺ concentration, making the solution more basic (alkaline). The normal pH range of body fluids, such as blood, is tightly regulated around 7.35–7.45.

Identify the role of buffer systems: Buffer systems in the body, such as the bicarbonate buffer system, help maintain pH homeostasis by resisting changes in pH. They do this by either releasing H⁺ ions when the pH increases (becomes more basic) or binding H⁺ ions when the pH decreases (becomes more acidic).

Describe the bicarbonate buffer system: The bicarbonate buffer system is the primary buffer in the blood. It involves the reversible reaction: \( \text{H}_2\text{CO}_3 \leftrightarrow \text{H}^+ + \text{HCO}_3^- \). When the pH increases, carbonic acid (\( \text{H}_2\text{CO}_3 \)) dissociates to release H⁺ ions, which helps lower the pH back to normal.

Explain the feedback mechanism: This process is an example of a negative feedback loop. Negative feedback loops work to counteract changes and restore balance. In this case, the buffer system acts to decrease the pH when it rises, maintaining homeostasis.

Summarize the importance: Buffer systems are critical for maintaining the stability of the body's internal environment. Without these systems, even small changes in pH could disrupt cellular processes and lead to severe physiological consequences.

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Key Concepts

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

Buffer Systems

Buffer systems in the body are chemical solutions that resist changes in pH when acids or bases are added. They work by neutralizing excess hydrogen ions (H+) or hydroxide ions (OH-), maintaining a stable pH in body fluids. Key buffers include bicarbonate, phosphate, and proteins, which play crucial roles in physiological processes.

pH Regulation

pH regulation is essential for maintaining homeostasis in the body, as enzymes and biochemical reactions are highly sensitive to pH changes. When the pH of body fluids increases (becomes more alkaline), buffer systems help to restore balance by releasing H+ ions to lower the pH back to normal levels, ensuring optimal functioning of cellular processes.

Negative Feedback Loop

A negative feedback loop is a biological mechanism that counteracts a change in a system to maintain stability. In the context of increased pH, the buffer systems act to lower the pH, demonstrating a negative feedback response. This process helps to return the body to its desired state, contrasting with positive feedback, which amplifies changes.

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Negative Feedback Loops

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Considering that water is a main component of the juices in the stomach and intestines, explain why digestion of lipids is more complicated than digestion of carbohydrates and proteins.

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In certain types of radioactive decay, the isotope releases a particle called an alpha particle, which contains two protons and two neutrons. When this happens, is the product still the same element? Why or why not?

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Textbook Question

Which of the following statements correctly describes a solution?

a. In a solution the solute is chemically dissolved by the solvent.

b. Solutions involve large particles suspended in another component.

c. The particles in a solution will settle out if left to sit.

d. The amount of solute in a solution is expressed as the solution's concentration.

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Textbook Question

Some claim that the pH of your blood can be affected by eating acidic foods such as citrus. Do you believe this to be true? Explain your answer. (Hint: What happens when extra hydrogen ions are added to the blood?)

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