The extracellular compartment comprises:
A. Cytosol and organelles
B. Interstitial fluid, blood, lymph
C. Bone, muscle, fat
D. Nucleus and mitochondria

B. Interstitial fluid, blood, lymph

Water is dipolar because it has:
A. Equal electron sharing
B. Pure ionic bonding
C. Uneven electron distribution
D. No partial charges

C. Uneven electron distribution

Water dissociation yields:
A. Na+ and Cl-
B. Ca2+ and CO3--
C. H2 and O2
D. H+ and OH-

D. H+ and OH-

pH is the:
A. Ratio of acid to base
B. Negative log of [H+]
C. Log of hydroxide
D. Measure of buffer amount

B. Negative log of [H+]

An acid is a substance that:
A. Releases hydrogen ions
B. Accepts hydrogen ions
C. Releases hydroxide ions
D. Accepts hydroxide ions

A. Releases hydrogen ions

A base is a substance that:
A. Releases hydrogen ions
B. Releases carbon dioxide
C. Accepts hydrogen ions
D. Accepts hydroxide ions

C. Accepts hydrogen ions

When a strong acid is added to water, it:
A. Forms a stable buffer
B. Does not dissociate
C. Accepts protons rapidly
D. Dissociates and releases H+

D. Dissociates and releases H+

A weak acid is characterized by its:
A. Dissociation constant Ka
B. Always complete dissociation
C. Fixed pH in water
D. Always negative charge

A. Dissociation constant Ka

pH, Ka, and dissociation are related by:
A. Nernst equation
B. Henderson–Hasselbalch equation
C. Michaelis–Menten equation
D. Gibbs–Helmholtz equation

B. Henderson–Hasselbalch equation

A buffer is a mixture of:
A. Two strong acids
B. Hydrogen and hydroxyl gases
C. Protein and lipid micelles
D. Undissociated acid and conjugate base

D. Undissociated acid and conjugate base

The acid form after losing its proton is the:
A. Parent acid
B. Carbonic acid
C. Conjugate base
D. Undissociated acid

C. Conjugate base

A buffer’s greatest capacity occurs when pH is:
A. Near the pKa
B. Far below pKa
C. Far above pKa
D. Independent of pKa

A. Near the pKa

Buffer effectiveness depends on:
A. Temperature and pressure
B. Volume and viscosity
C. pKa–pH relation, concentration
D. Osmolarity and hemoglobin

C. pKa–pH relation, concentration

The major source of acid from normal metabolism is:
A. Phosphate
B. Carbon dioxide
C. Bicarbonate
D. Chloride

B. Carbon dioxide

Normal metabolism generates:
A. Ketones only
B. CO2 only
C. Inorganic acids only
D. CO2, metabolic, inorganic acids

D. CO2, metabolic, inorganic acids

CO2 reacting with water produces:
A. Carbonic acid
B. Lactic acid
C. Hydrochloric acid
D. Phosphoric acid

A. Carbonic acid

Bicarbonate, phosphate, and hemoglobin act as:
A. Enzymes
B. Buffers
C. Hormones
D. Transporters

B. Buffers

Respiratory removal of carbonic acid occurs via:
A. Excreting NH4+ in urine
B. Sweating bicarbonate
C. Expiring CO2
D. Storing H+ in bone

C. Expiring CO2

Renal excretion of acid occurs mainly as:
A. H2O
B. CO2
C. HCO3-
D. NH4+

D. NH4+

Reference range for blood pH is:
A. 7.36–7.44
B. 7.20–7.28
C. 7.10–7.18
D. 7.52–7.60

A. 7.36–7.44

Complete reduction of molecular O2 requires:
A. Four electrons
B. Two electrons
C. One electron
D. Three electrons

A. Four electrons

Obese patients tend to have lower % body water because:
A. Glycogen holds little water
B. Fat holds little water
C. Bone holds little water
D. Muscle holds little water

B. Fat holds little water

Approximate total body water distribution is:
A. 60% ICF, 40% ECF
B. 40% ICF, 60% ECF
C. 50% ICF, 50% ECF
D. 70% ICF, 30% ECF

A. 60% ICF, 40% ECF

Extracellular water is found mainly in:
A. Cytosol and organelles
B. Nucleus and mitochondria
C. Bone and adipose
D. Plasma and interstitial fluid

D. Plasma and interstitial fluid

Transcellular water is best described as:
A. Majority intracellular volume
B. Specialized extracellular fluid portion
C. Entire interstitial compartment
D. Entire lymphatic compartment

B. Specialized extracellular fluid portion

In water, shared electrons are attracted to the ___, creating a ___.
A. Oxygen, partial negative
B. Hydrogen, partial negative
C. Oxygen, partial positive
D. Hydrogen, partial positive

A. Oxygen, partial negative

A hydrogen bond is a:
A. Covalent electron sharing
B. Ionic attraction between ions
C. Hydrophobic solute clustering
D. Weak H-to-electronegative bond

D. Weak H-to-electronegative bond

Each water molecule is typically hydrogen-bonded to:
A. Two neighbors
B. Four neighbors
C. Six neighbors
D. Eight neighbors

B. Four neighbors

What dissolves easily in water?
A. Neutral lipids and sterols
B. Nonpolar hydrocarbons
C. Polar organics, inorganic salts
D. Noble gases and waxes

C. Polar organics, inorganic salts

Hydrogen bonds between water and polar solutes continuously:
A. Permanently lock solutes
B. Dissociate and reform
C. Convert to covalent bonds
D. Prevent water channel flow

B. Dissociate and reform

Water’s high heat of fusion allows it to:
A. Boil at low heat
B. Rapidly change temperature
C. Resist temperature change
D. Have low specific heat

C. Resist temperature change

With heat input, water responds by:
A. Decreases hydrogen bonding
B. Increases hydrogen bonding
C. Forms ionic lattices
D. Eliminates dipole forces

A. Decreases hydrogen bonding

With cooling, water responds by:
A. Decreases hydrogen bonding
B. Breaks covalent bonds
C. Eliminates dipole forces
D. Increases hydrogen bonding

A. Decreases hydrogen bonding

“Electrolytes” here refers to:
A. Proteins and lipids
B. Bicarbonate and inorganic ions
C. Glucose and urea
D. Vitamins and hormones

B. Bicarbonate and inorganic ions

Major electrolytes in ECF are:
A. K+ and phosphate
B. Ca2+ and Mg2+
C. Na+ and Cl-
D. H+ and lactate

C. Na+ and Cl-

Major electrolytes inside cells are:
A. K+ and phosphates
B. Na+ and chloride
C. Calcium and bicarbonate
D. Glucose and urea

A. K+ and phosphates

Hydration shells primarily surround:
A. Neutral gases
B. Lipid droplets
C. Proteins only
D. Anions and cations

D. Anions and cations

Osmolality is proportional to:
A. Sodium concentration only
B. Total solute concentration
C. Plasma proteins only
D. Fluid volume only

B. Total solute concentration

Osmotic pressure is the:
A. Force moving solute outward
B. Force creating ion gradients
C. Force keeping water equal sides
D. Force measuring membrane thickness

C. Force keeping water equal sides

When water is lost into urine, blood volume water is resupplied by:
A. Interstitial fluid refill
B. Intracellular fluid refill
C. Bone mineral release
D. Transcellular fluid refill

A. Interstitial fluid refill

Ka for a weak acid (HA) is:
A. Ka = [A-]/[HA]
B. Ka = [H+]/[HA]
C. Ka = [HA]/[H+][A-]
D. Ka = [H+][A-]/[HA]

D. Ka = [H+][A-]/[HA]

The midpoint of a titration curve is:
A. pH equals pKa
B. pH equals pOH
C. pH equals 7.00
D. pH equals Ka

A. pH equals pKa

The bicarbonate buffer system primarily occurs in:
A. Red blood cells
B. Intracellular fluid
C. Extracellular fluid
D. Mitochondrial matrix

C. Extracellular fluid

The hemoglobin buffer system primarily occurs in:
A. Extracellular fluid
B. Red blood cells
C. Blood plasma only
D. Interstitial fluid only

B. Red blood cells

The phosphate buffer system occurs in:
A. All cell types
B. Red blood cells only
C. Extracellular fluid only
D. Plasma only

A. All cell types

The initial acid–base effect of aspirin is:
A. Metabolic alkalosis
B. Respiratory acidosis
C. Metabolic acidosis
D. Respiratory alkalosis

D. Respiratory alkalosis

Aspirin is a weak acid. When aspirin binds H⁺ (is protonated), it exists primarily in which chemical form?
A. Salicylate
B. Acetic acid
C. Acetylsalicylic acid
D. Salicylic acid

C. Acetylsalicylic acid

Salicylate interferes most with production of:
A. Nuclear DNA
B. Cytosolic NADH
C. Mitochondrial ATP
D. Hemoglobin heme

C. Mitochondrial ATP

Salicylate may also impair:
A. Platelet ADP receptors
B. Renal function
C. Pulmonary surfactant
D. Hepatic bile flow

B. Renal function

Carbonic anhydrase accelerates:
A. HCO3- → CO2
B. Lactate → pyruvate
C. NH3 → NH4+
D. CO2 + H2O → H2CO3

D. CO2 + H2O → H2CO3

Carbonic acid dissociates into:
A. Na+ and Cl-
B. H+ and HCO3-
C. H+ and OH-
D. CO2 and H2O

B. H+ and HCO3-

In these notes, the pKa of carbonic acid is:
A. 6.1
B. 4.8
C. 3.8
D. 7.4

C. 3.8

Carbonic anhydrase is not found in:
A. Plasma and interstitial fluid
B. Renal tubular cells
C. Red blood cells
D. Gastric parietal cells

A. Plasma and interstitial fluid

Major buffers maintaining ICF pH are:
A. Phosphate anions and proteins
B. Bicarbonate and hemoglobin
C. Sodium and chloride
D. Lactate and ketones

A. Phosphate anions and proteins

Hydrogen ion transport helps maintain:
A. Constant urine pH
B. Constant gastric pH
C. Constant intracellular pH
D. Constant plasma pH

C. Constant intracellular pH

If a cell becomes more acidic, exchange moves:
A. HCO3- in; Cl- out
B. Na+ in; H+ in
C. H+ out; K+ in
D. H+ out; Na+ in

D. H+ out; Na+ in

If a cell becomes too alkaline, exchange moves:
A. HCO3- in; Cl- out
B. HCO3- out; Cl- in
C. H+ in; Na+ out
D. NH4+ out; H+ in

B. HCO3- out; Cl- in

A major source of nonvolatile acid is:
A. Carbonic acid
B. Lactic acid
C. Sulfuric acid
D. Acetic acid

C. Sulfuric acid

Sulfuric acid is generated by:
A. Sulfates + sulfur amino acids
B. Glucose oxidation
C. Fatty acid beta-oxidation
D. Ketone dissociation

A. Sulfates + sulfur amino acids

Major contributor to urinary buffering, not blood:
A. Bicarbonate
B. Hemoglobin
C. Phosphate
D. Ammonium

D. Ammonium

Gastric HCl is secreted by ___ to:
A. Parietal cells; denature proteins
B. Chief cells; emulsify fats
C. G cells; activate pepsin
D. Enterocytes; absorb glucose

A. Parietal cells; denature proteins

Gastric acid is neutralized in small intestine by:
A. Bile acids secretion
B. Mucus release
C. Pancreatic bicarbonate secretion
D. Gastrin release

C. Pancreatic bicarbonate secretion

DKA most directly reflects:
A. Acid loss in urine
B. Acid accumulation, type 1
C. CO2 retention, COPD
D. Excess bicarbonate, vomiting

B. Acid accumulation, type 1

A patient suspected of salicylate toxicity is most likely to have:
A. Lower abdominal pain
B. Respiratory stimulation
C. Chest tightness
D. Peripheral edema

A. Lower abdominal pain

Which symptom is NOT listed for salicylate toxicity?
A. Nausea
B. Headache
C. Upper abdominal distress
D. Tinnitus

D. Tinnitus

Because solutes can only be excreted dissolved in water, renal water loss is primarily determined by the amount of water needed to:
A. Dilute excreted solutes
B. Replace sweat losses
C. Maintain plasma proteins
D. Raise blood pressure

A. Dilute excreted solutes

A buffer works best within:
A. Three pH of pKa
B. One pH of pKa
C. Five pH of pKa
D. Ten pH of pKa

B. One pH of pKa

pKa is calculated as:
A. log Ka
B. -log pH
C. -log Ka
D. log[H+]

C. -log Ka

Normal metabolism generates which set?
A. CO2 and bicarbonate only
B. Lactate and bicarbonate only
C. CO2 and phosphate only
D. Lactate, ketones, sulfuric HCl, CO2

D. Lactate, ketones, sulfuric HCl, CO2

CO2 reacting with water forms:
A. Carbonic acid
B. Hydrochloric acid
C. Sulfuric acid
D. Lactic acid

A. Carbonic acid

Salicylate overdose causes respiratory alkalosis by:
A. Suppressing medullary drive
B. Reducing CO2 production
C. Blocking renal ammoniagenesis
D. Stimulating medullary respiratory center

D. Stimulating medullary respiratory center

Salicylate raises CO2 and lactate mainly because:
A. ATP falls; glycolysis rises
B. ATP rises; glycolysis falls
C. CO2 excretion stops
D. Lactate oxidation accelerates

A. ATP falls; glycolysis rises

Salicylate may worsen metabolic acidosis by:
A. Increasing bicarbonate generation
B. Increasing chloride retention
C. Renal dysfunction accumulates strong acids
D. Decreasing ketone production

C. Renal dysfunction accumulates strong acids

Henderson–Hasselbalch equation is:
A. pH = -log[H+]
B. pH=pKa+log(A-/HA)
C. Ka=[HA]/[H+][A-]
D. pKa = -log pH

B. pH=pKa+log(A-/HA)

When a weak acid is 50% dissociated:
A. pH equals pKa
B. pH equals 7.40
C. pH equals pOH
D. pH equals Ka

A. pH equals pKa

Total body water distribution is:
A. 40% ICF; 60% ECF
B. 70% ICF; 30% ECF
C. 50% ICF; 50% ECF
D. 60% ICF; 40% ECF

D. 60% ICF; 40% ECF

In these notes, “ICF” components include:
A. Transcellular fluid only
B. Urine and sweat
C. Plasma and interstitial
D. RBC cytosol only

C. Plasma and interstitial

ED rehydration for uncomplicated dehydration uses:
A. 0.9% saline
B. 5% dextrose
C. 3% saline
D. 0.45% saline

A. 0.9% saline

High filtrate glucose and ketones causing polyuria is:
A. SIADH
B. Osmotic diuresis
C. Nephritic syndrome
D. Diabetes insipidus

B. Osmotic diuresis

Ka best represents a weak acid’s:
A. Buffer capacity
B. Tendency to donate H+
C. Ability to bind OH-
D. Rate of oxidation

B. Tendency to donate H+

A higher Ka generally means the acid:
A. Dissociates less in water
B. Dissociates more in water
C. Becomes a stronger base
D. Becomes more hydrophobic

B. Dissociates more in water

Normal arterial blood pH is:
A. 7.10–7.20
B. 7.26–7.34
C. 7.36–7.44
D. 7.46–7.54

C. 7.36–7.44

Intracellular pH normally ranges:
A. 6.9–7.4
B. 7.36–7.44
C. 7.8–8.2
D. 6.0–6.5

A. 6.9–7.4

“Typical” intracellular pH is about:
A. 6.9
B. 7.1
C. 7.4
D. 7.6

B. 7.1

Carbonic acid (H2CO3) dissociates into:
A. H+ and Cl-
B. Na+ and HCO3-
C. H+ and HCO3-
D. CO2 and H2O

C. H+ and HCO3-

In blood, carbonic acid “can’t buffer” because:
A. Too little dissolved CO2
B. Almost fully dissociated
C. No bicarbonate present
D. No hemoglobin present

B. Almost fully dissociated

When base removes H+, H2CO3 shifts to:
A. H+ and HCO3-
B. CO2 and H2O
C. H+ and CO3--
D. NH4+ and HCO3-

A. H+ and HCO3-

As base is added, dissolved CO2 + H2O replenishes:
A. NH3
B. HCO3-
C. H2CO3
D. H2PO4-

C. H2CO3

Dissolved CO2 availability is adjusted mainly by:
A. Liver gluconeogenesis rate
B. Breathing rate and CO2 expiry
C. Sweat rate and sodium loss
D. Renal albumin excretion

B. Breathing rate and CO2 expiry

RBCs contain high amounts of:
A. Carbonic anhydrase
B. Acetylcholinesterase
C. Lipoprotein lipase
D. Catalase only

A. Carbonic anhydrase

Carbonic anhydrase is absent from:
A. RBC cytosol
B. Renal tubules
C. Blood plasma and interstitial
D. Gastric mucosa

C. Blood plasma and interstitial

In RBCs, released H+ is buffered by:
A. Albumin
B. Hemoglobin
C. Bicarbonate
D. Phosphate only

B. Hemoglobin

Anion exported from RBC for chloride is:
A. Lactate
B. Phosphate
C. Sulfate
D. Bicarbonate

D. Bicarbonate

Plasma/interstitial buffering capacity comes from:
A. Bicarbonate and carbonic acid
B. Hemoglobin and phosphate
C. Lactate and ketones
D. Sodium and chloride

A. Bicarbonate and carbonic acid

Blood buffering capacity includes:
A. Only phosphate buffers
B. Only carbonic acid
C. Albumin and side chains
D. CO2 in alveoli

C. Albumin and side chains

Interstitial protein buffering is limited because:
A. Proteins cannot accept H+
B. Protein concentration is low
C. Proteins are membrane-bound
D. Proteins are rapidly degraded

B. Protein concentration is low

Major ICF buffer in these notes is:
A. Bicarbonate
B. Hemoglobin
C. Phosphate anions
D. Carbonic acid

C. Phosphate anions

Examples of ICF phosphate buffers include:
A. ATP, G6P, H2PO4-
B. NaCl, KCl, CaCl2
C. CO2, H2CO3, HCO3-
D. Albumin, globulin, fibrinogen

A. ATP, G6P, H2PO4-

Major intracellular buffer in RBCs is:
A. Phosphate
B. Bicarbonate
C. Lactate
D. Sulfate

A. Phosphate

In these notes, phosphate is higher in:
A. Interstitial than blood
B. Blood than interstitial
C. Plasma than intracellular
D. CSF than blood

B. Blood than interstitial

Many ICF proteins buffer via:
A. Histidine residues
B. Tryptophan residues
C. Phenylalanine residues
D. Leucine residues

A. Histidine residues

Metabolic anions leave cells together with:
A. OH-
B. CO2
C. H+
D. NH3

C. H+

Sulfuric acid arises from metabolism of:
A. Lysine and leucine
B. Tyrosine and tryptophan
C. Cysteine and methionine
D. Alanine and glycine

C. Cysteine and methionine

Nonvolatile acids are excreted mainly via:
A. Lungs
B. Sweat glands
C. Urine
D. Saliva

C. Urine

With cooling, water responds by:
A. Decreases hydrogen bonding
B. Breaks covalent bonds
C. Eliminates dipole forces
D. Increases hydrogen bonding

D. Increases hydrogen bonding

Urinary pH buffering range listed is:
A. 3.0–4.0
B. 4.5–5.0
C. 5.5–7.0
D. 7.2–7.6

C. 5.5–7.0

Minimum urinary pH listed is:
A. 5.0
B. 5.5
C. 6.0
D. 7.0

A. 5.0

Acid secretion includes all EXCEPT:
A. Phosphate
B. Ammonium
C. Uric acid
D. Creatinine

D. Creatinine

NH3 is kept low in blood because:
A. It is renal-limited
B. It is neurally toxic
C. It is insoluble
D. It is rapidly exhaled

B. It is neurally toxic

As tubules secrete H+ into urine, they return:
A. Chloride to blood
B. Lactate to blood
C. Bicarbonate to blood
D. Sulfate to blood

C. Bicarbonate to blood

Main ammonium form in blood/urine is:
A. NH3
B. NH4+
C. NO3-
D. NH2-

B. NH4+

pKa of ammonium in these notes is:
A. 3.8
B. 6.1
C. 9.25
D. 9.8

C. 9.25

Urinary excretion that helps remove acid:
A. CO3--
B. HPO4--
C. H2PO4-
D. H2CO3

C. H2PO4-

Urinary phosphate form depends on:
A. Urine pH and blood pH
B. Plasma glucose and ketones
C. Hemoglobin and albumin
D. CO2 diffusion gradient

A. Urine pH and blood pH

Dehydration occurs when intake is less than:
A. Renal plus extrarenal loss
B. Only renal water loss
C. Only sweat loss
D. Only respiratory loss

A. Renal plus extrarenal loss

Dehydration causes:
A. Increased Total body water, decreased ECF
B. Decreased Total body water, ECF, ICF
C. Increased Total body water, increased ICF
D. Decreased Total body water, increased ECF

B. Decreased Total body water, ECF, ICF

Daily water loss in expired air and urine solute:
A. About 40 mL/day
B. About 400 mL/day
C. About 4 L/day
D. About 40 L/day

B. About 400 mL/day

Dehydration can occur during:
A. Only fasting
B. Only high-salt intake
C. Fasting and normal intake
D. Only prolonged exercise

C. Fasting and normal intake