68. Physiology - Acid Base I

The body's internal environment is split into distinct, interacting fluid compartments, including bone, plasma, interstitial fluid, intracellular fluid, and red blood cell intracellular fluid.

The overall balance of acids and bases in the body, often measured by arterial blood or extracellular fluid pH.

Usually, the pH of extracellular fluid (ECF), is considered to reflect the body's pH overall.

The body creates acids during the breakdown of food (carbohydrates, lipids).

Volatile acids are easily removed by the lungs (e.g., carbonic acid), while non-volatile acids are removed by the kidneys.

Maintaining the correct pH is critical to ensure enzymes and other proteins function properly.

The body removes excess acids by either exhaling volatile acids (e.g., Carbon Dioxide, as a byproduct of carbonic acid) or through kidney excretion of non-volatile acids.

A chemical system in the body that regulates pH by controlling the balance between carbon dioxide (CO2) and bicarbonate (HCO3-).

Partial pressure of carbon dioxide (CO2) in a fluid.

The body regulates CO2 levels primarily through the lungs by controlling alveolar ventilation.

The rate at which air flows in and out of the alveoli (tiny air sacs in the lungs).

The kidneys regulate nonvolatile acids, such as sulfuric acid, through excretion.

Maintaining the balance of hydrogen ions (H+) in body fluids to maintain a healthy pH level.

The body exchanges materials and energy with the external environment, affecting the levels of acid in the body.

The kidneys remove excess acid from the body, regulating pH.

Acids that are produced within the body, not from carbon dioxide, such as sulfuric acid.

A disruption in the body's delicate balance between acids and bases, leading to an abnormal pH level.

Chronic Obstructive Pulmonary Disease (COPD) can cause an accumulation of carbonic acid in body fluids due to impaired gas exchange in the lungs.

A complication of uncontrolled diabetes where the body produces excessive amounts of ketones, leading to an excess of non-carbonic acids.

The ability of a dissolved substance to minimize changes in pH when a strong acid or base is added to the solution.

Substances that completely ionize (break apart into charged particles) when dissolved in a solution, like table salt (NaCl) or hydrochloric acid (HCl).

Substances that only partially ionize when dissolved in a solution, for example, lactic acid or ketoacids.

A substance that can donate or release hydrogen ions (H+) in a solution.

A substance that can accept or take up hydrogen ions (H+) in a solution.

The remaining part of an acid molecule after it has donated a proton (H+).

A measure of the strength of a weak acid, indicating how readily it dissociates (breaks apart) into its charged components (ions).

Carbonic anhydrase, an enzyme crucial for acid-base balance, is present in red blood cells and epithelial cells involved in transport, such as those in the kidney tubules and the choroid plexus of the brain.

Carbonic anhydrase catalyzes the reversible reaction between carbon dioxide (CO2) and water (H2O) to form carbonic acid (H2CO3).

Carbonic acid (H2CO3) readily dissociates into hydrogen ions (H+) and bicarbonate ions (HCO3-), impacting the pH of the solution.

The concentrations of carbon dioxide (pCO2), pH, and bicarbonate (HCO3-) are interconnected and governed by the equilibrium constant (Ka') of the carbonic acid reaction.

The Henderson-Hasselbalch equation provides a mathematical relationship between pCO2, pH, and [HCO3-], allowing calculation of one variable if the other two are known.

When the pH of a solution is close to the pK value of the buffer (in this case, carbonic acid), there is minimal change in pH for each added acid or base molecule.

The titration curve for imidazole, a critical buffer in the body, shows a nearly linear relationship between pH and the amount of added acid or base between pH 6.5 and 7.5.

A type of titration curve specifically for imidazole, used to assess buffering capacity and acid-base balance.

The Henderson-Hasselbalch equation describes the relationship between pCO2, pH, and [HCO3-] even in complex acid-base disorders. However, it doesn't diagnose the specific disorder.

While the Henderson-Hasselbalch equation governs the chemical equilibrium of acid-base balance, it's the physiological processes that cause the changes in pCO2, pH, and [HCO3-].

Lines on the Davenport Diagram that represent constant partial pressure of CO2 (pCO2). Each isobar represents a different pCO2 value for the body fluids.

A curve on the Davenport Diagram that depicts the change in pH of a solution as you add an acid or base to it. Each curve represents a fixed pCO2 value.

The point on the Davenport Diagram representing the typical, healthy pH, pCO2, and [HCO3-] values for a human at sea level.

Adding strong acid (e.g., HCl) to a solution will shift the point along the isobar downwards. This means the pH will decrease and the bicarbonate concentration ([HCO3-]) will also decrease.