Ch. 2 Chemistry Comes Alive

Hoehn - Marieb Human Anatomy & Physiology, 12th edition

Hoehn, Haynes, Abbott12th EditionMarieb Human Anatomy & PhysiologyISBN: 9780138242732Not the one you use?Change textbook

Hoehn, Haynes, Abbott 12th Edition

Ch. 2 Chemistry Comes Alive

Problem 26

Chapter 2, Problem 26

Jason, a 12-year-old boy, was awakened suddenly by a loud crash. As he sat up in bed, straining to listen, his fright was revealed by his rapid breathing (hyperventilation), a breathing pattern effective in ridding the blood of CO₂. At this point, was his blood pH rising or falling?

Verified step by step guidance

Step 1: Understand the relationship between CO₂ and blood pH. Carbon dioxide (CO₂) in the blood combines with water to form carbonic acid, which dissociates into hydrogen ions (H⁺) and bicarbonate (HCO₃⁻). The reaction is: \[\mathrm{CO_2 + H_2O \leftrightarrow H_2CO_3 \leftrightarrow H^+ + HCO_3^-}\] More CO₂ means more H⁺ ions, which lowers pH (making blood more acidic).

Step 2: Recognize that hyperventilation causes rapid breathing, which expels CO₂ from the lungs faster than it is produced. This decreases the partial pressure of CO₂ in the blood (hypocapnia).

Step 3: With less CO₂ in the blood, the equilibrium shifts to reduce hydrogen ion concentration, leading to a decrease in acidity and thus an increase in blood pH (making it more alkaline).

Step 4: Conclude that during hyperventilation, because CO₂ is being removed quickly, the blood pH is rising (becoming more basic).

Step 5: Summarize that Jason’s rapid breathing is causing respiratory alkalosis, a condition where blood pH increases due to excessive loss of CO₂.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Video duration:

Was this helpful?

Key Concepts

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

Hyperventilation and CO₂ Levels

Hyperventilation is rapid or deep breathing that causes excessive expulsion of carbon dioxide (CO₂) from the blood. This reduction in CO₂ decreases the amount of carbonic acid in the blood, which directly affects blood pH.

Blood pH and Acid-Base Balance

Blood pH measures how acidic or basic the blood is, normally around 7.4. A decrease in CO₂ leads to less carbonic acid, causing the blood to become more alkaline, thus raising the pH (respiratory alkalosis). Conversely, increased CO₂ lowers pH (acidosis).

Respiratory Regulation of Blood pH

The respiratory system helps regulate blood pH by controlling CO₂ levels through breathing rate. When CO₂ is expelled faster than produced, as in hyperventilation, blood pH rises. This is a key mechanism in maintaining acid-base homeostasis.

Recommended video:

07:58

pH Scale

Related Practice

Textbook Question

Mrs. Roberts, in a diabetic coma, has just been admitted to Noble Hospital. Her blood pH indicates that she is in severe acidosis (low blood pH), and measures are quickly instituted to bring her blood pH back within normal limits.

a. Define pH and note the normal pH of blood.

b. Why is severe acidosis a problem?

views

Textbook Question

Some antibiotics act by binding to certain essential enzymes in the target bacteria.

a. How might these antibiotics influence the chemical reactions controlled by the enzymes?

b. What is the anticipated effect on the bacteria? On the person taking the antibiotic prescription?

views

Textbook Question

Explain why, if you pour water into a glass very carefully, you can 'stack' the water slightly above the rim of the glass.

views

Textbook Question

After you eat a protein bar, which chemical reactions introduced in this chapter must occur for the amino acids in the protein bar to be converted into proteins in your body cells?

views