Carbon Dioxide Transport and Acid Base Balance

Carbon dioxide is transported in the blood primarily in the form of bicarbonate (HCO3-),which is released when carbonic acid dissociates. Bicarbonate can buffer H+, and thus helps to maintain a normal arterial pH. Hypoventilation raises, and hyperventilation lowers, the carbonic acid concentration of the blood.

Carbon dioxide is carried by the blood in three forms: (1) as dissolved CO2—carbon dioxide is about twenty-one times more soluble than oxygen in water, and about one-tenth of the total blood CO2 is dissolved in plasma; (2) as carbaminohemo-globin—about one-fifth of the total blood CO2 is carried attached to an amino acid in hemoglobin (carbaminohemoglobin should not be confused with carboxyhemoglobin, which is a combination of hemoglobin and carbon monoxide); and (3) as bicarbonate ion, which accounts for most of the CO2 carried by the blood.

Carbon dioxide is able to combine with water to form carbonic acid. This reaction occurs spontaneously in the plasma at a slow rate, but it occurs much more rapidly within the red blood cells because of the catalytic action of the enzyme carbonic an-hydrase. Since this enzyme is confined to the red blood cells, most of the carbonic acid is produced there rather than in the plasma. The formation of carbonic acid from CO2 and water is favored by the high PCO2 found in tissue capillaries (this is an example of the law of mass action, described in chapter 4).

carbonic anhydrase

high PCO2

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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Responses

  • Lavinia Grubb
    What is the normal ratio of bicarbonate to dissolved carbon dioxide?
    7 years ago
  • Lara
    How is co2 transported around body, acid base balance?
    7 years ago
  • stefanie
    How is co2 transported in the body maintains acid base balance?
    7 years ago
  • ky
    What Acid base balance does in phisiology?
    7 years ago
  • roosa
    When carbon dioxide is carried in the blood primarily by attaching to the amino acids in globin.?
    7 years ago
  • THORSTEN
    How carbon dioxide is transported in human blood primarily?
    7 years ago
  • Sarah
    Is carbon dioxide primarily transported in blood as carbonic acid?
    7 years ago
  • aran
    Is CO2 prmiarily transported as H?
    6 years ago
  • Callie
    How does the acidbase balance affect carbon dioxide transport?
    3 years ago
  • pinja
    How co2 heps to maintatain blood acid base balance?
    1 year ago
  • Nino
    What the three main forms in which carbon dioxide is transported in the blood?
    1 month ago
  • hagosa omar
    What is the primary form in which carbon dioxide is carried in blood?
    1 month ago

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