ANS 230: Acid Base I and II

What does the term "pH" stand for in a physiologic context?

Potential of hydrogen.

What is the mathematical formula used to calculate pH?

$pH = -log_{10} [H^{+}]$.

How does a large accumulation of free $[H^{+}]$ lead to cell death?

It binds to proteins, altering their charge, shape, and function.

Cells and enzymes function optimally when $[H^{+}]$ is at what concentration?

$40 \times 10^{-9}\ Eq/L$ (or $40\ nEq/L$).

What is the standard physiologic pH resulting from a $[H^{+}]$ of $40\ nEq/L$?

$7.4$.

In the pH log function, what is the relationship between $[H^{+}]$ and pH level?

An inverse, non-linear relationship where pH decreases as $[H^{+}]$ increases.

What biological process constantly produces $CO_{2}$ and $[H^{+}]$ within cells?

Normal metabolism.

Approximately what percentage of $CO_{2}$ is removed from the body by being dissolved in plasma?

$10\%$.

Which system acts as the primary buffer for $CO_{2}$ removal, handling roughly $70\%$ of transport?

Bicarbonate ions.

Complete the chemical equation for the primary buffer system: $CO_{2} + H_{2}O \leftrightarrow H_{2}CO_{3} \leftrightarrow$ _____.

$HCO_{3}^{-} + H^{+}$.

Which enzyme is responsible for the rapid conversion of $CO_{2}$ and $H_{2}O$ into carbonic acid?

Carbonic anhydrase.

What are the three chemical buffers that respond within seconds to maintain pH balance?

Bicarbonate, phosphates, and proteins (such as hemoglobin).

How long does it typically take for the respiratory system to adjust pH through ventilation?

Minutes.

What is the typical timeframe for the renal system to respond to acid-base imbalances?

Hours to days.

The respiratory system maintains acid-base balance primarily by adjusting the levels of which substance?

$CO_{2}$.

The renal system maintains pH by either reabsorbing $HCO_{3}^{-}$ or by _____ $[H^{+}]$.

Excreting.

What is the primary laboratory change associated with metabolic acidosis?

Low $HCO_{3}^{-}$.

How does the body compensatorily respond to metabolic acidosis?

Hyperventilation to blow off $CO_{2}$.

What is the primary laboratory change associated with metabolic alkalosis?

High $HCO_{3}^{-}$.

How does the body compensatorily respond to metabolic alkalosis?

Hypoventilation to retain $CO_{2}$.

What is the primary change seen in respiratory acidosis?

High $CO_{2}$.

How do the kidneys compensate for respiratory acidosis?

By excreting $[H^{+}]$ and retaining $HCO_{3}^{-}$.

What is the primary change seen in respiratory alkalosis?

Low $CO_{2}$.

How do the kidneys compensate for respiratory alkalosis?

By retaining $[H^{+}]$ and excreting $HCO_{3}^{-}$.

Which functional group in the protein buffer system acts as a weak acid?

The carboxyl group ($-COOH$).

Which functional group in the protein buffer system acts as a weak base?

The amine group ($-NH_{2}$).

What type of diet generally leads to a low (acidic) urine pH?

A high-protein diet.

What type of diet generally leads to a high (alkaline) urine pH?

A diet high in plants and fiber.

Why do Urinary Tract Infections (UTIs) often lead to an alkaline urine pH?

Urease-producing bacteria convert urea into ammonia.

Under what condition does glucosuria occur?

When glucose levels exceed the renal threshold.

In cats, what physiological state besides diabetes can lead to hyperglycemia and glucosuria?

Stress.

The presence of ketones in urine indicates a metabolic shift to what type of metabolism?

Lipid (fat) metabolism.

Why are ketone bodies specifically linked to metabolic acidosis?

They lower the blood pH.

Which ketone body is typically not detected or marked with an 'X' in common urinalysis evaluations?

Beta-hydroxybutyric acid.

List the three ketone bodies identified in the evaluation of urine chemistry.

Acetoacetic acid, Acetone, and Beta-hydroxybutyric acid.

What is the normal urine volume range for a dog?

$14-50\ ml/kg$.

What is the normal urine volume range for a cat?

$18-25\ ml/kg$.

What is the characteristic transparency of normal horse urine?

Turbid.

Which species is noted for having a "garlicy" urine odor?

Dog.

Which species is noted for having a "sharp" urine odor?

Cat.

What is the normal color range for rabbit urine?

Pale yellow to red brown.

Why is a high $[H^{+}]$ necessary in the stomach lumen?

To initiate the digestion of proteins.

Why does hydrochloric acid ($HCl$) dissociate completely in the stomach without being buffered?

The $Cl^{-}$ anion will not bind to $[H^{+}]$.

How does the positive charge acquired by proteins in the stomach affect their digestion?

It alters their shape so that pepsin can hydrolyze them.

On a rumen pH graph, what is the effect of a high-grain diet compared to a high-forage diet?

A high-grain diet causes a significant drop in pH, often below $5.8$.

Which species has an aromatic urine odor and a color range from pale yellow to dark brown yellow?

Cattle.

Based on the provided graphs, what pH value is considered the neutral midpoint for physiologic acid-base balance?

$7.4$.

In the erythrocyte, which molecule buffers the $[H^{+}]$ produced from the dissociation of carbonic acid?

Hemoglobin.

What transport protein facilitates the movement of water, though labeled next to $[H^{+}]$ in cell diagrams?

Aquaporin.

A pH of $7.2$ on the physiologic scale is categorized as which clinical state?

Acidemia.

A pH of $7.6$ on the physiologic scale is categorized as which clinical state?

Alkalemia.

What percentage of $CO_{2}$ removal is handled by hemoglobin as carbamino compounds?

Approximately $20\%$.

What is the characteristic color of horse urine described in the parameters table?

Ochre.

Urine volume for humans is typically measured as _____ per day.

$1-2\ L$.

Which ketone body is marked as having the highest presence (indicated by multiple checkmarks) in urine chemistry?

Acetoacetic acid.

In the protein buffer system diagram, what charge does the amine group take when it binds an extra hydrogen ion?

Positive ($+$).

What is the primary anion secreted by the stomach along with $[H^{+}]$?

$Cl^{-}$.

How does the log function affect the visual representation of the $[H^{+}]$ vs. pH relationship?

It creates a curve rather than a straight line.

What is the primary function of pepsin in the stomach?

To hydrolyze proteins.

In a high-forage diet (4:6 LG), what is the approximate pH of the rumen at 3 hours post-feeding?

Approximately $6.1$.