Regulation of Blood pH in the Human Body

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BIO 311C Final Map

luonut Alana Beard

2

luonut AUVIN OGHATIYAN

Balance: This Generative topic is applicable to different areas of science such as chemistry but also applicable to our health like our diet and in sports, law, and time management.

luonut Allison Thayne

Unit 4 Respiration

luonut Jayde Mahelona

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Regulation of Blood pH in the Human Body

Acid-Base Disorders (medical applications)

Alkalosis (pH > 7.45)

Metabolic Alkalosis

high HCO₃⁻ or low acid

Acidosis (pH < 7.35)

Metabolic Acidosis

low HCO₃⁻ or high acid

Renal System (Kidneys)

The nephron

Key areas

Collecting Duct

traps H⁺ using NH₃ →NH₄⁺ (pee)

Distal tubule

Proximal tubule

metabolizes glutamine → 2 NH₄⁺ + 2 HCO₃⁻

Mechanisms

Secrete H⁺

Reabsorb HCO₃

slower response (hours–days)

excretion of H⁺ and reabsorption of HCO₃⁻

Respiratory System

CO₂ regulation

Le Chatelier’s Principle

CO₂ decreases, equilibrium shifts left → fewer H⁺ → higher pH

CO₂ increases, equilibrium shifts right → more H⁺ → lower pH

↑CO₂ → ↑H₂CO₃ → ↑H⁺ → ↓pH ↓CO₂ → ↓H⁺ → ↑pH

Hyperventilation (↑ breathing rate):

CO₂ eliminated rapidly

Respiratory Alkalosis

Hypoventilation (↓ breathing rate)

CO₂ accumulates

Respiratory Acidosis

Buffer Systems

solutions that can resist pH change upon the addition of an acidic or basic components.

Ammonia Buffer System (Kidneys)

NH3+H+→NH4+

NH₃ freely diffuses, NH₄⁺ is trapped in urine and excreted

Generates new HCO₃⁻ for each H⁺ secreted

Protein Buffers

Hemoglobin in red blood cells

Reduces Hemoglobin's affinity for O₂ (facilitates delivery)

Bohr effect

Binds H⁺ directly

deoxygenated Hemoglobin binds more CO₂ and H⁺

Haldane Effect

Phosphate Buffer System

Urine & Intracellular Fluid

generate new bicarbonate (Le Chatelier’s Principle)

H2PO4−⇌H++HPO42

excrete H⁺ in kidneys via NaH₂PO₄ (acidic salt)

Bicarbonate Buffer System (Main System in Blood)

Act instantly to resist pH changes

CO2+H2O⇌H2CO3 H2CO3⇌H++HCO3

Sources of acid in the body

Other metabolic acids

Dietary intake or drug metabolism

Ketone bodies

fat metabolism, diabetic ketoacidosis

Lactic acid

anaerobic exercise

Cellular Respiration

CO2+H2O↔H2CO3 H2CO3 ↔H+ +HCO3−

carbonic acid dissociating into bicarbonate and hydrogen ions

Normal Blood pH

7.35 – 7.45 (arterial blood)

Ionization of intermediates in biochemical pathways

Oxygen delivery (Bohr effect)

Enzyme activity