Why are glucose and ketone bodies passing into the urine?
Because their blood levels are high, leading to their filtration in the kidneys.
p.2
Henderson-Hasselbalch Equation
What equation can be used to calculate the ratio of unprotonated to protonated form of a weak acid at any pH?
The Henderson-Hasselbalch equation.
p.7
Respiratory Compensation
What happens to CO2 as red blood cells approach the lungs?
CO2 is released, causing more carbonic acid to dissociate into CO2 and water.
What metabolic condition can result from the dissociation of salicylic acid?
Complex metabolic acidosis.
p.7
Buffer Systems in the Body
What is the pKa of the side chain of the amino acid histidine in hemoglobin?
6.7, allowing it to accept a proton.
p.7
Buffer Systems in the Body
What role does hemoglobin play in buffering H+ within red blood cells?
It buffers H+ generated from cellular metabolism.
p.5
Bicarbonate Buffer System
What does CO2(d) refer to in the bicarbonate buffer system?
Carbon dioxide dissolved in water, not in the gaseous state.
p.4
Buffer Systems in the Body
What is the consequence of adding more hydrogen ions to a buffered solution?
The pH would fall rapidly due to relatively little conjugate base remaining.
p.6
Henderson-Hasselbalch Equation
What constant is combined with pKa to modify the Henderson-Hasselbalch equation?
Kh, the hydration constant for the reaction of water and CO2 to form H2CO3.
p.7
Buffer Systems in the Body
Why can't interstitial fluid serve as an effective buffer?
It has a low protein content compared to blood.
p.6
Bicarbonate Buffer System
How is HCO3– expressed in terms of concentration?
As milliequivalents per milliliter (mEq/mL).
p.4
Buffer Systems in the Body
What is the pH range that a buffer can effectively compensate for hydrogen ion influx or removal?
Approximately 1 pH unit of its pKa.
p.7
Respiratory Compensation
What is the effect of hyperventilation on blood pH?
It raises blood pH, potentially leading to respiratory alkalosis.
p.5
Bicarbonate Buffer System
How can carbonic acid be replenished in the body?
From CO2 in body fluids and air.
p.8
Clinical Implications of Diabetes
What condition is indicated by fasting plasma glucose values between 100 and 126 mg/dL?
Impaired fasting glucose or prediabetes.
What are the weak acids mentioned that partially dissociate?
Acetoacetic acid and β-hydroxybutyric acid.
p.4
Buffer Systems in the Body
What happens to the ratio of [A−] to HA when the pH changes from pKa to one unit below pKa?
It changes from 1:1 to 1:10.
p.2
Buffer Systems in the Body
What is the role of buffers in a solution?
They allow a solution to resist changes in pH when hydrogen ions or hydroxide ions are added.
p.9
Respiratory Compensation
What compensatory mechanism occurs during diabetic ketoacidosis (DKA)?
Stimulation of the respiratory center leading to Kussmaul breathing.
p.10
Clinical Implications of Diabetes
How do comatose patients lose water?
Through the skin and sweat glands.
p.2
Buffer Systems in the Body
What do buffers consist of?
A weak acid and its conjugate base.
p.8
Buffer Systems in the Body
What is the effect of ammonia (NH3) in the body?
It combines with protons to produce ammonium (NH4+), helping to buffer pH.
p.10
Clinical Implications of Diabetes
What experience did Percy V. have that relates to dehydration?
He experienced anorexia during his depression.
What type of acid is sulfuric acid?
A strong acid that dissociates into H+ ions and sulfate.
What happens to water as a result of osmotic diuresis?
Water passes from inside cells into the interstitial space and blood, causing intracellular dehydration.
What metabolic acids are produced from fatty acid oxidation?
Acetoacetic acid and β-hydroxybutyric acid.
p.6
Henderson-Hasselbalch Equation
How is dissolved CO2 expressed in blood components measured in the emergency department?
As a fraction of the partial pressure of CO2 in arterial blood (PaCO2).
p.7
Bicarbonate Buffer System
What is the significance of the bicarbonate buffer system?
It is intimately linked to the delivery of oxygen to tissues.
How is sulfuric acid generated in the body?
From sulfate-containing compounds ingested in foods and from the metabolism of sulfur-containing amino acids.
p.6
Bicarbonate Buffer System
What happens to carbonic acid (H2CO3) in red blood cells?
It dissociates, releasing H+ which is buffered by hemoglobin (Hb).
p.3
Henderson-Hasselbalch Equation
What is the significance of the midpoint in a titration curve?
It represents the pKa, where 50% dissociation occurs.
p.10
Clinical Implications of Diabetes
What can result in dehydration related to appetite?
Anorexia, as it reduces food intake which is a source of fluid.
How do ketone bodies affect blood pH?
They increase H+ levels, lowering blood pH.
p.9
Clinical Implications of Diabetes
What indicates an increased risk for diabetes based on HbA1C values?
Values between 5.7% and 6.4%.
p.6
Henderson-Hasselbalch Equation
What is the relationship between [H+] and pH?
A 10-fold change in [H+] changes the pH by 1 unit.
p.9
Bicarbonate Buffer System
What is the role of bicarbonate in the body during DKA?
Bicarbonate levels decrease as acidosis develops.
What are the symptoms of respiratory alkalosis due to hyperventilation?
Light-headedness and paresthesias.
p.10
Clinical Implications of Diabetes
What happens to patients who are debilitated and unable to swallow?
They continue to lose water and become dehydrated.
p.3
Henderson-Hasselbalch Equation
What happens when more OH− ions are added to a buffer solution?
More conjugate acid molecules (HA) dissociate to generate H+ ions, which combine with OH− to form water, resulting in a small increase in pH.
p.7
Bicarbonate Buffer System
How is bicarbonate transported out of red blood cells?
In exchange for chloride anions.
What does Ka represent in acid dissociation?
The equilibrium constant for the dissociation of a weak acid.
What does a higher Ka indicate?
A greater tendency to dissociate a proton.
p.4
Buffer Systems in the Body
What are the major buffer systems in the body?
Bicarbonate-carbonic acid buffer system, hemoglobin buffer system, phosphate buffer system, and protein buffer system.
What is the significance of serum glucose levels in DKA?
Serum glucose levels can be extremely high, contributing to osmotic diuresis.
p.10
Clinical Implications of Diabetes
How can cerebral injuries contribute to dehydration?
They can cause a loss of thirst response.
At what pH is a weak acid 50% dissociated?
At a pH equal to its pKa.
What is the consequence of high osmolarity in the glomerular filtrate?
Increased water excretion in the urine, resulting in polyuria.
p.2
Clinical Implications of Diabetes
How does salicylate affect mitochondrial ATP production?
It interferes with ATP production, acting as an uncoupler.
p.9
Clinical Implications of Diabetes
How is diabetes mellitus diagnosed using HbA1C values?
A value of ≥ 6.5% HbA1C defines diabetes mellitus.
p.5
Bicarbonate Buffer System
What happens to bicarbonate when H+ ions are present?
Bicarbonate combines with protons to form H2CO3, lowering bicarbonate levels.
p.2
Henderson-Hasselbalch Equation
What occurs at the midpoint of a titration curve for a weak acid?
Half of the conjugate acid has dissociated, so [A−] equals [HA].
What happens to blood pH during DKA?
Blood pH decreases, leading to acidosis.
What is diabetic ketoacidosis (DKA)?
A metabolic acidosis that develops due to the accumulation of weak acids from ketone bodies.
p.3
Henderson-Hasselbalch Equation
What does pKa represent in the Henderson-Hasselbalch equation?
The pH at which 50% dissociation occurs.
p.3
Henderson-Hasselbalch Equation
What occurs when hydrogen ions are added to a buffer at its pKa?
Conjugate base molecules (A−) combine with the added hydrogen ions to form HA, resulting in almost no fall in pH.
p.3
Henderson-Hasselbalch Equation
In the context of a titration curve for acetic acid, what does HA represent?
HA represents the weak acid in the buffer system.
What is the initial effect of aspirin ingestion on respiration?
It produces respiratory alkalosis by stimulating the central respiratory control center.
p.7
Buffer Systems in the Body
What is the pKa of inorganic phosphate anion H2PO4−?
7.2, allowing it to generate H+ and its conjugate base HPO4²−.
What happens to children who ingest toxic amounts of aspirin?
They are usually acidotic by the time they arrive in the emergency department.
p.9
Clinical Implications of Diabetes
What are normal HbA1C levels?
4% to 5.6% of total hemoglobin.
p.6
Bicarbonate Buffer System
What role do red blood cells play in buffering blood?
They contain high amounts of carbonic anhydrase, converting CO2 to carbonic acid (H2CO3).
What causes dehydration in the context of diabetes?
Osmotic diuresis due to high serum glucose levels.
p.7
Buffer Systems in the Body
What is the role of phosphate anions in maintaining intracellular pH?
They act as major buffers in red blood cells and other cell types.
What is the effect of dehydrated brain cells?
They are unable to carry out their normal functions, which can lead to a coma.
What is the major source of metabolic acid in the body?
Carbon dioxide (CO2) produced from fuel oxidation in the TCA cycle.
p.5
Bicarbonate Buffer System
Why is carbonic acid unable to buffer effectively at a blood pH of 7.4?
It is almost completely dissociated at that pH.
p.8
Urinary Excretion of Acids
What role do ammonium ions play in the body?
They are major contributors to buffering urinary pH.
p.8
Clinical Implications of Diabetes
What is the significance of fasting plasma glucose levels below 100 mg/dL?
They are considered normal.
p.8
Urinary Excretion of Acids
What happens when a cell becomes too alkaline?
More bicarbonate is transported out in exchange for Cl- ions.
How much CO2 does the body generate per day under normal metabolic conditions?
More than 13 mol (approximately 0.5 to 1 kg).
p.5
Bicarbonate Buffer System
What occurs when a base is added and H+ is removed from the bicarbonate buffer system?
H2CO3 dissociates into hydrogen and bicarbonate ions.
