Untitled Quiz

Acid and Base Concepts

• Acids release protons (H+) in water, acting as proton donors.
• Bases accept protons (H+) in water, or release hydroxide ions (OH-).
• Strong acids dissociate completely in solution. Examples include HCl, H2SO4, HNO3.
• Weak acids partially dissociate. Examples include formic acid (HCOOH), acetic acid (CH3COOH), oxalic acid (C2H2O4), benzoic acid (C6H5COOH), lactic acid, phosphoric acid, carbonic acid, and citric acid.
• Strong bases completely dissociate into ions in solution. Examples include NaOH, KOH, Ba(OH)2.
• Weak bases do not completely dissociate. Examples include amines, NH4+, aniline, and pyridine.
• The tendency of an acid to lose a proton is its dissociation constant (Ka).
• pKa is the negative logarithm of Ka and is a measure of acid strength; a smaller pKa signifies a stronger acid.
• The body maintains a stable pH through buffering.
• Buffers are mixtures of weak acids (proton donors) and their conjugate bases (proton acceptors).
• Buffers resist changes in pH upon addition of acids or bases.
• Important examples of buffers in the human body include bicarbonate-carbonic acid buffers, phosphate and proteins.
• The kidneys help regulate pH by excreting hydrogen ions and generating bicarbonate.
• The respiratory system regulates pH by adjusting breathing rate to control carbon dioxide levels.

Acids Produced in the Human Body

• Carbonic acid (H2CO3) is produced through the oxidation of carbon compounds.
• Other acids found include phosphoric acid (H3PO4) and sulfuric acid (H2SO4).
• Organic acids such as lactate, acetoacetate, and pyruvate are also produced.

Alkaline Substances in the Human Body

• Citrate and bicarbonates are examples of alkaline substances.

pH Scale

• pH is a measure of hydrogen ion concentration in a solution.
• pH scale ranges from 0 to 14.
• Values below 7 are acidic.
• A pH of 7 is neutral.
• Values above 7 are alkaline (basic).

Acid-Base Balance

• Acid-base balance refers to the mechanisms the body uses to maintain a relatively constant pH in its fluids.
• The normal pH for arterial blood is 7.35-7.45.
• Imbalances in pH (acidosis or alkalosis) can disrupt cellular function.

Acid-Base Disorders

• Acidosis occurs when arterial blood pH drops below 7.35.
• Alkalosis occurs when arterial blood pH rises above 7.45.
• Acidosis and alkalosis can have various causes, including respiratory or metabolic origins.

Buffer Systems

• Buffers maintain relatively constant pH by absorbing or releasing hydrogen ions.
• Important buffers in blood include bicarbonate-carbonic acid buffers, phosphate, and proteins (e.g., hemoglobin).
• The bicarbonate buffering system is critical for extracellular fluids.

Anion Gap

• The difference between measured cations and anions.
• This is helpful for diagnosing acid-base imbalances.
• Causes can involve increased unmeasured anions (e.g., ketoacidosis) or decreased unmeasured anions.
• Usually a value of approximately 15 mEq/L.

Calculation of Anion Gap

• Calculated using the formula (Na+ + K+) - (Cl- + HCO3-), where Na+ and K+ are cations and Cl- and HCO3- are anions.

Significance of Anion Gap Calculation

• Helps diagnose acid-base imbalances, particularly metabolic acidosis.

Respiratory Acidosis/Alkalosis

• Respiratory acidosis is caused by excess CO2 in the blood, while respiratory alkalosis is caused by insufficient CO2 in the blood.

Metabolic Acidosis/Alkalosis

• Metabolic acidosis is caused by excessive acid in the blood, while metabolic alkalosis is caused by excessive base in the blood.

Importance of Biological Buffers

• Maintaining homeostasis
• Regulating enzymatic function.
• Controlling pH in biochemical reactions.

Types of Buffer Systems

• Bicarbonate buffer system: The primary buffer in extracellular fluids; involves equilibrium between CO₂, H₂O, H₂CO₃, H⁺, and HCO₃⁻.
• Phosphate buffer system: The primary buffer in intracellular fluids; involves equilibrium between H₂PO₄⁻, HPO₄²⁻, and H⁺.
• Protein buffer system: Includes hemoglobin in the blood and proteins within cells. These proteins contain amino acid residues with carboxyl and amino groups that can accept or donate H⁺, thus acting as buffers.

Case Study

• A patient in the hospital with a history of a cardiac event, lab results show abnormal pH, HCO3- and pCO2 indicating a metabolic and respiratory acidosis disturbance.