Acid-Base Homeostasis Practice Flashcards

Comprehensive practice questions covering acid-base homeostasis, including definitions, physiological responses, disorders, and clinical treatments.

To what does the term acid-base balance specifically refer?

The regulation of free (unbound) hydrogen ion ($H^+$) concentration in body fluids.

How are acids defined in the context of acid-base balance?

$H^+$ linked substances that dissociate in solution to liberate free $H^+$.

What is an example of an acid provided in the transcript?

$$CO_2$$

What is the definition of a base?

A chemical that will remove $H^+$ ions from a solution.

What is the primary example of a base used in the body fluids?

Bicarbonate ($HCO_3^-$).

A change of $1$ pH unit corresponds to what magnitude of change in hydrogen ion concentration?

A $10$-fold change.

What is the normal pH range of blood?

$7.35$ to $7.45$

Why is the pH of venous blood slightly lower than arterial blood?

Due to the $H^+$ generation that accompanies the creation of $H_2CO_3$ from $CO_2$.

At what blood pH levels is the condition usually fatal?

Below $6.8$ or above $7.8$.

What are the primary clinical manifestations of pH abnormalities?

Changes in excitability of nerve and muscle cells.

How does acidosis specifically affect synaptic transmission?

It decreases synaptic transmission; a pH around $7$ can produce coma.

How does alkalosis specifically affect clinical presentation?

It increases synaptic transmission; a pH of $7.8$ to $8$ can produce severe convulsions.

Which metabolic process produces lactic acid?

Anaerobic respiration of glucose.

What acid is produced by protein breakdown?

Phosphoric acid.

What are the three regulating mechanisms that maintain $H^+$ concentration?

Chemical Buffers, Respiratory mechanisms, and Renal mechanisms.

What is the major buffering system in the extracellular fluid (ECF)?

The bicarbonate ($HCO_3^-$) - carbonic acid ($H_2CO_3$) buffer.

What is the reaction for the bicarbonate-carbonic acid buffer mechanism?

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

According to the transcript, which protein is the main plasma protein buffer?

Albumin

Which buffer is technically intracellular but significantly impacts ECF pH?

Hemoglobin

How much more acid or base can the respiratory system handle compared to chemical buffers?

Twice as many acids and bases.

How do lungs respond to a fall in pH (excess $CO_2$)?

Faster, deeper breathing eliminates $CO_2$, forming less $H_2CO_3$, causing pH to rise.

What is the normal range for $HCO_3^-$ levels?

$22$ to $26,mEq/L$

How long does it take for the renal system to start restoring normal pH?

The kidneys may take $24$ hours before starting.

How is acidemia defined?

A decrease in the blood pH below the normal range of $7.35-7.45$.

What is the definition of acidosis as a process?

A process that increases [$H^+$] by increasing $PCO_2$ or by reducing [$HCO_3^-$].

What characterizes respiratory acidosis?

Excess $CO_2$ retention (high $PCO_2$) resulting from hypoventilation.

In respiratory acidosis, what happens if $H^+$ overwhelms compensatory mechanisms?

$H^+$ ions move into the cells and $K^+$ ions move out.

What are common causes of respiratory acidosis?

CNS depression (drugs/injury), asphyxia, and hypoventilation from cardiac or pulmonary dysfunction.

What pulmonary treatments are used for respiratory acidosis?

Bronchodilators, supplemental oxygen, and chest physiotherapy.

What causes respiratory alkalosis?

Excess $CO_2$ excretion (low $PCO_2$) due to hyperventilation.

What physiological effect does hypocapnia have on the brain?

Cerebral vasoconstriction, leading to decreased blood flow and potentially cerebral hypoxia.

How can hyperventilation from anxiety be counteracted according to the notes?

By having the patient breathe into a bag or use a rebreather mask to rebreathe exhaled $CO_2$.

What is metabolic acidosis?

Acid retention or $HCO_3^-$ loss, indicated by a low $HCO_3^-$ level.

What are common causes of metabolic acidosis?

$HCO_3^-$ depletion through diarrhea, inadequate acid excretion from renal disease, or excess acid production from liver disease/shock.

Why is rapid-acting insulin used in treating diabetic ketoacidosis (metabolic acidosis)?

To reverse ketoacidosis and drive $K^+$ back into the cells.

What is metabolic alkalosis?

$HCO_3^-$ retention or acid loss, indicated by high [$HCO_3^-$].

What are the common causes of metabolic alkalosis?

Loss of hydrochloric acid from vomiting/gastric suction, loss of $K^+$ from diuretics/steroids, or excessive alkali ingestion.

Which medication can be used to increase renal excretion of $HCO_3^-$ in metabolic alkalosis?

Acetazolamide

What does 'Base Excess' (BE) indicate in an arterial blood gas test?

The amount of base that needs to be removed to bring the pH back to normal.

What is the normal $PaCO_2$ range specifically for Salt Lake Valley?

$$34-41,mm,Hg$$