Acid-Base Balance Review

Flashcards covering the fundamentals of acid-base balance, including chemical definitions, physiological responses to pH changes, and compensation mechanisms.

How is an acid defined?

A substance that releases hydrogen ions ($H^+$) when dissolved in water.

How is a base defined?

A substance that combines with free $H^+$ ions and removes them from solution.

What is the function of a buffer?

A substance that resists changes in pH when acids or bases are added.

What is the normal range for blood pH?

$$7.35-7.45$$

How does acidosis affect the central nervous system (CNS)?

Neurons become less excitable, causing CNS depression.

How does alkalosis affect the central nervous system (CNS)?

Neurons become hyperexcitable.

What defines acidosis?

Blood pH below $7.35$.

What defines alkalosis?

Blood pH above $7.45$.

What is the primary respiratory acid in the body?

Carbonic acid ($H_2CO_3$) formed from $CO_2$.

What are two examples of inorganic metabolic acids?

Sulfuric acid ($H_2SO_4$) and phosphoric acid ($H_3PO_4$).

What are three examples of organic metabolic acids?

Lactic acid, fatty acids, and ketone acids.

What are the three main mechanisms that control blood pH?

Chemical buffers, respiratory system, and kidneys.

Which acid-base control mechanism acts the fastest?

Chemical buffer systems.

Which acid-base control mechanism acts the slowest?

Kidneys.

Which mechanism is responsible for eliminating fixed acids?

The kidneys.

Identify the main extracellular buffer system.

Carbonic acid-bicarbonate buffer system.

What is the most abundant buffer system in the body?

Protein buffer system.

Where are protein buffers located?

Inside cells (intracellular proteins) and in hemoglobin.

In which two locations is the phosphate buffer system particularly important?

Inside cells and in urine.

What is the role of the respiratory system in maintaining acid-base balance?

It eliminates $CO_2$ and therefore decreases $H^+$.

What is the chemical equation for the acid-base reaction at the tissues?

$$CO_2 + H_2O \rightarrow H_2CO_3 \rightarrow H^+ + HCO_3^-$$

What is the chemical equation for the acid-base reaction at the alveoli?

$$H^+ + HCO_3^- \rightarrow H_2CO_3 \rightarrow CO_2 + H_2O$$

What occurs during respiratory compensation for acidosis?

Hyperventilation occurs to remove $CO_2$ and raise the pH.

What occurs during respiratory compensation for alkalosis?

Hypoventilation occurs to retain $CO_2$ and lower the pH.

How do the kidneys respond to a state of acidosis?

They increase $H^+$ secretion and increase $HCO_3^-$ reabsorption.

How do the kidneys respond to a state of alkalosis?

They increase $HCO_3^-$ excretion and reabsorb $H^+$.

What are the three specific renal mechanisms for pH control?

$HCO_3^-$ reabsorption, $H^+$ secretion, and $NH_3$ secretion.

What characterizes respiratory acidosis?

High $PCO_2$ and low pH caused by hypoventilation.

What are the common causes of respiratory acidosis?

Hypoventilation, airway obstruction, emphysema, and pulmonary edema.

How does the body compensate for respiratory acidosis?

The kidneys increase $H^+$ excretion and $HCO_3^-$ reabsorption.

What characterizes respiratory alkalosis?

Low $PCO_2$ and high pH caused by hyperventilation.

What are the common causes of respiratory alkalosis?

Hyperventilation, anxiety, and oxygen deficiency.

How does the body compensate for respiratory alkalosis?

The kidneys decrease $H^+$ excretion and $HCO_3^-$ reabsorption.

What characterizes metabolic acidosis?

Low $HCO_3^-$ and low pH.

What are the common causes of metabolic acidosis?

Diarrhea, ketoacidosis, and renal dysfunction.

What is the primary compensation mechanism for metabolic acidosis?

Hyperventilation.

What characterizes metabolic alkalosis?

High $HCO_3^-$ and high pH.

What are the common causes of metabolic alkalosis?

Vomiting, antacid overuse, and endocrine disorders.

What is the primary compensation mechanism for metabolic alkalosis?

Hypoventilation.

What is the memory trick for respiratory compensation?

Acid = Hyperventilate; Base = Hypoventilate.