Homeostasis of pH and Acid-Base Disorders

Vocabulary flashcards covering pH homeostasis, buffer systems, and primary acid-base disorders based on the lecture transcript.

Acid

Substances that produce hydrogen ions or protons when dissolved in water (e.g., $HCl \rightarrow H^+ + Cl^-$).

Base

Substances that produce hydroxyl ions or accept protons when dissolved in water (e.g., $NaOH \rightarrow Na^+ + OH^-$).

Normal Arterial Blood pH

The homeostatic pH range of human arterial blood, which is $7.35 - 7.45$.

Volatile Acid

The most abundant acid in the body ($H_2CO_3$), formed during cellular respiration from $CO_2 + H_2O \rightleftharpoons H_2CO_3 \rightleftharpoons HCO_3^- + H^+$.

Non-Volatile Acids

Metabolic acid byproducts that accumulate in the body, such as lactic acid from anaerobic metabolism and sulfuric or phosphoric acids from protein metabolism.

Buffers

Chemical systems that either accept or release $H^+$ to minimize changes in free $H^+$ concentration, acting as the first line of defense against pH changes.

Bicarbonate Buffer System

The primary extracellular buffer system ($CO_2/H_2CO_3/HCO_3^-$), regulated by the kidneys via $HCO_3^-$ and the lungs via $CO_2$.

Phosphate Buffer System

An intracellular and renal buffer system consisting of dibasic phosphate ($HPO_4^{2-}$) and monobasic phosphate ($H_2PO_4^-$) used by renal tubules to excrete $H^+$ as titratable acid.

Protein Buffer System

The most abundant buffer system in intracellular fluid and plasma, utilizing carboxyl and amino groups of amino acids, hemoglobin in RBCs, and albumin in plasma.

Carbonic Anhydrase

The enzyme in red blood cells that catalyzes the reversible reaction $CO_2 + H_2O \rightleftharpoons H_2CO_3 \rightleftharpoons H^+ + HCO_3^-$.

Metabolic Acidosis

An acid-base disorder characterized by a primary decrease in the serum bicarbonate ($HCO_3^-$) concentration.

Metabolic Alkalosis

An acid-base disorder characterized by a primary increase in the serum bicarbonate ($HCO_3^-$) concentration.

Respiratory Acidosis

An acid-base disorder characterized by a primary increase in arterial carbon dioxide ($PCO_2$) concentration, also known as hypercapnia.

Respiratory Alkalosis

An acid-base disorder characterized by a primary decrease in arterial carbon dioxide ($PCO_2$) concentration, also known as hypocapnia.