Chapter 25 Flashcards by Omar A

An acid is a substance that ______ a proton

Donates

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Acidity: ____ concentration of hydrogen ions

High

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A base is a substance that ______ a proton

Accepts

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Basicity: ___ concentration of hydrogen ions

Low

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Describe neutrality

[H+] = [OH-] in pure water (1 x 10^-7 mol/L)

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What does a high pH indicate? How is the solution classified?

Few hydrogen ions; alkaline (basic)

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What does a low pH indicate? How is the solution classified?

Many hydrogen ions; acidic

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What happens to cellular function when body fluid pH is abnormal?

Proteins lose function; vital organs fail

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What does pH indicate?

Net result of acid-base regulation and compensatory response

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What does PaCO2 indicate?

Respiratory function

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What does HCO3 indicate?

Renal (metabolic) function

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What are the three mechanisms regulating acid-base balance?

Buffers, respiratory system, renal system

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First line of defense against _____________

pH changes

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What are buffers?

Chemicals that help control pH

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Describe buffer components

Weak acids (release H⁺), bases (take up H⁺)

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What are the types of buffers?

Bicarbonate, phosphate, hemoglobin, protein

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Primary defense against _______

Acid-base disorders

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Components of bicarbonate buffer system

Bicarbonate ions (HCO₃⁻), carbonic acid (H₂CO₃)

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What is a volatile acid?

An acid excreted by lungs (as gas)

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What is the only volatile acid in the body?

Carbonic acid (H₂CO₃)

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Function of buffer: too much acid

Bicarbonate binds H⁺ → carbonic acid → lungs exhale CO₂

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Function of buffer: too little acid

Releases H⁺ from carbonic acid to lower pH

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What do lungs control?

CO₂ (acid portion)

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What do kidneys control?

H⁺ excretion and HCO₃⁻ addition

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Second defense against ________

Acid-base disorders

What do lungs secrete?

CO₂ and water

Why do lungs secrete CO₂ and water?

To remove carbonic acid

Excessive carbonic acid → _______

Increased rate and depth of respiration

What happens with insufficient carbonic acid?

Respiration slows to retain CO₂

What does PaCO₂ indicate?

Effectiveness of lungs excreting carbonic acid

Respiratory compensatory response: deficit of metabolic acid

Hypoventilation

Respiratory compensatory response: excess metabolic acid

Hyperventilation

The lungs can excrete only __________ acid

Carbonic

Carbonic acid is the only type of ______ acid in the body

Volatile

The lungs cannot excrete ____________ acids

Nonvolatile (e.g., lactic acid, ketones)

Respiratory compensation begins in ______ and requires ______

Minutes; several hours for full effect

Third defense against _________

Acid-base disorders

What acids can kidneys excrete?

All except carbonic acid

Describe increased H⁺ excretion

More NH₃ produced; H⁺ binds NH₃; excreted as NH₄⁺

Describe slow H⁺ excretion

Less NH₃, less H⁺ excreted; more reabsorbed

Decreased HCO₃⁻ in plasma means...

Excess metabolic acid

Increased HCO₃⁻ in plasma means...

Deficit of metabolic acid

Renal compensation: high carbonic acid

↑ excretion of metabolic acids and H⁺

Renal compensation: low carbonic acid

↓ excretion of metabolic acids and H⁺; excrete HCO₃⁻

Renal compensation requires ______

Several days

What are the four primary disorders?

Metabolic acidosis, respiratory acidosis, metabolic alkalosis, respiratory alkalosis

What is metabolic acidosis?

Excess acid (not carbonic) or loss of base

Causes of metabolic acidosis?

DKA, lactic acidosis, renal failure, diarrhea, poisons

Clinical manifestations of metabolic acidosis

Headache, CNS depression, confusion, coma, dysrhythmias

Compensatory correction in metabolic acidosis

↓ PaCO₂ (via hyperventilation)

How is metabolic acidosis diagnosed?

↓ HCO₃⁻, ↓ PaCO₂, low or normal pH (compensated)

What causes respiratory acidosis?

CO₂ retention from lung dysfunction (e.g., COPD, pneumonia)

Clinical manifestations of respiratory acidosis?

Headache, blurred vision, tremors, lethargy, tachycardia

Compensation for respiratory acidosis

↑ renal H⁺ excretion and HCO₃⁻ retention

Lab findings in respiratory acidosis

↑ PaCO₂, normal or ↑ HCO₃⁻, ↓ HCO₃⁻/H₂CO₃ ratio

Causes of metabolic alkalosis?

Vomiting, suctioning, HCO₃⁻ ingestion, diuretics

Clinical manifestations of metabolic alkalosis?

Weakness, hypokalemia, tetany, tingling, seizures

What may coexist with metabolic alkalosis?

Hypokalemia

Compensatory mechanisms for metabolic alkalosis

↓ respiration, ↑ renal HCO₃⁻ excretion

Death from metabolic alkalosis occurs if...

pH rises to 7.8

What causes respiratory alkalosis?

Hyperventilation (anxiety, pain, fever, drugs)

Clinical manifestations of respiratory alkalosis?

Paresthesias, confusion, vasoconstriction, carpal spasm

Compensatory mechanisms for respiratory alkalosis

↑ renal HCO₃⁻ excretion, ↓ reabsorption

How is respiratory alkalosis diagnosed?

↑ HCO₃⁻/H₂CO₃ ratio, ↓ PaCO₂, alkaline urine