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WGU D236 PATHOPHYSIOLOGY OA EXAM
2025 UPDATED ACTUAL EXAM WITH
CORRECT SOLUTIONS.
What is Starling's Law of Capillary forces?
How does this explain why a nutritionally deficient child would
have edema? - correct answer- Starling's Law describes how
fluids move across the capillary membrane. There are two
major opposing forces that act to balance each other,
hydrostatic pressure (pushing water out of the capillaries) and
osmotic pressure (including oncontic pressure, which pushes
fluid into the capillaries).
Both electrolytes and proteins (oncontic pressure) in the blood
affect osmotic pressure, high electrolyte and protein
concentrations in the blood would cause water to leave the
cells and interstitial space and enter the blood stream to dilute
the high concentrations.
On, the other hand, low electrolyte and protein concentrations
(as seen in a nutritionally deficient child) would cause water to
leave the capillaries and enter the cells and interstitial fluid
which can lead to edema.
How does the RAAS (Renin-Angiotensin-Aldosterone System)
result in increased blood volume and increased blood
,2 | Page
pressure? - correct answer- A drop in blood pressure is sensed
by the kidneys by low perfusion, which in turn begins to secrete
renin.
Renin then triggers the liver to produce angiotensinogen, which
is converted to Angiotensin I in the lungs and then angiotensin
II by the enzyme
Angiotensin-converting enzyme (ACE). Angiotensin II
stimulates peripheral arterial vasoconstriction which raises BP.
Angiotensin II is also stimulating the adrenal gland to release
aldosterone, which acts to increase sodium and water
reabsorption increasing blood volume, while also increased
potassium secretion in urine.
How can hyperkalemia lead to cardiac arrest? - correct answer-
Normal levels of potassium are between 3.5 and 5.2 mEq/dL.
Hyperkalemia refers to potassium levels higher that 5.2
mEq/dL.
A major function of potassium is to conduct nerve impulses in
muscles. Too low and muscle weakness occurs and too much
can cause muscle spasms.
This is especially dangerous in the heart muscle and an
irregular heartbeat can cause a heart attack
,3 | Page
The body uses the Protein Buffering System, Phosphate
Buffering System, and Carbonic Acid-Bicarbonate System to
regulate and maintain homeostatic pH, what is the
consequence of a pH imbalance - correct answer- Proteins
contain many acidic and basic group that can be affected by pH
changes. Any increase or decrease in blood pH can alter the
structure of the protein (denature), thereby affecting its function
as well
Describe the laboratory findings associated with metabolic
acidosis, metabolic alkalosis, respiratory acidosis and
respiratory alkalosis. (ie relative pH and CO2 levels). - correct
answer- Normal ABGs (Arterial Blood Gases) Blood pH: 7.35-
7.45 PCO2: 35-45 mm Hg PO2: 90-100 mm Hg HCO3-: 22-26
mEq/L SaO2: 95-100%
Respiratory acidosis and alkalosis are marked by changes in
PCO2. Higher = acidosis and lower = alkalosis
Metabolic acidosis and alkalosis are caused by something
other than abnormal CO2 levels. This could include toxicity,
diabetes, renal failure or excessive GI losses.
Here are the rules to follow to determine if is respiratory or
metabolic in nature. -If pH and PCO2 are moving in opposite
directions, then it is the pCO2 levels that are causing the
imbalance and it is respiratory in nature.
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-If PCO2 is normal or is moving in the same direction as the
pH, then the imbalance is metabolic in nature.
The anion gap is the difference between measured cations
(Na+ and K+) and measured anions (Cl- and HCO3-), this
calculation can be useful in determining the cause of metabolic
acidosis.
Why would an increased anion gap be observed in diabetic
ketoacidosis or lactic acidosis? - correct answer- The anion gap
is the calculation of unmeasured anions in the blood.
Lactic acid and ketones both lead to the production of
unmeasured anions, which remove HCO3- (a measured anion)
due to buffering of the excess H+ and therefore leads to an
increase in the AG.
Why is it important to maintain a homeostatic balance of
glucose in the blood (ie describe the pathogenesis of
diabetes)? - correct answer- Insulin is the hormone responsible
for initiating the uptake of glucose by the cells. Cells use
glucose to produce energy (ATP).
In a normal individual, when blood glucose increases, the
pancreas is signaled to produced in insulin, which binds to
insulin receptors on a cells surface and initiates the uptake of
glucose.
WGU D236 PATHOPHYSIOLOGY OA EXAM
2025 UPDATED ACTUAL EXAM WITH
CORRECT SOLUTIONS.
What is Starling's Law of Capillary forces?
How does this explain why a nutritionally deficient child would
have edema? - correct answer- Starling's Law describes how
fluids move across the capillary membrane. There are two
major opposing forces that act to balance each other,
hydrostatic pressure (pushing water out of the capillaries) and
osmotic pressure (including oncontic pressure, which pushes
fluid into the capillaries).
Both electrolytes and proteins (oncontic pressure) in the blood
affect osmotic pressure, high electrolyte and protein
concentrations in the blood would cause water to leave the
cells and interstitial space and enter the blood stream to dilute
the high concentrations.
On, the other hand, low electrolyte and protein concentrations
(as seen in a nutritionally deficient child) would cause water to
leave the capillaries and enter the cells and interstitial fluid
which can lead to edema.
How does the RAAS (Renin-Angiotensin-Aldosterone System)
result in increased blood volume and increased blood
,2 | Page
pressure? - correct answer- A drop in blood pressure is sensed
by the kidneys by low perfusion, which in turn begins to secrete
renin.
Renin then triggers the liver to produce angiotensinogen, which
is converted to Angiotensin I in the lungs and then angiotensin
II by the enzyme
Angiotensin-converting enzyme (ACE). Angiotensin II
stimulates peripheral arterial vasoconstriction which raises BP.
Angiotensin II is also stimulating the adrenal gland to release
aldosterone, which acts to increase sodium and water
reabsorption increasing blood volume, while also increased
potassium secretion in urine.
How can hyperkalemia lead to cardiac arrest? - correct answer-
Normal levels of potassium are between 3.5 and 5.2 mEq/dL.
Hyperkalemia refers to potassium levels higher that 5.2
mEq/dL.
A major function of potassium is to conduct nerve impulses in
muscles. Too low and muscle weakness occurs and too much
can cause muscle spasms.
This is especially dangerous in the heart muscle and an
irregular heartbeat can cause a heart attack
,3 | Page
The body uses the Protein Buffering System, Phosphate
Buffering System, and Carbonic Acid-Bicarbonate System to
regulate and maintain homeostatic pH, what is the
consequence of a pH imbalance - correct answer- Proteins
contain many acidic and basic group that can be affected by pH
changes. Any increase or decrease in blood pH can alter the
structure of the protein (denature), thereby affecting its function
as well
Describe the laboratory findings associated with metabolic
acidosis, metabolic alkalosis, respiratory acidosis and
respiratory alkalosis. (ie relative pH and CO2 levels). - correct
answer- Normal ABGs (Arterial Blood Gases) Blood pH: 7.35-
7.45 PCO2: 35-45 mm Hg PO2: 90-100 mm Hg HCO3-: 22-26
mEq/L SaO2: 95-100%
Respiratory acidosis and alkalosis are marked by changes in
PCO2. Higher = acidosis and lower = alkalosis
Metabolic acidosis and alkalosis are caused by something
other than abnormal CO2 levels. This could include toxicity,
diabetes, renal failure or excessive GI losses.
Here are the rules to follow to determine if is respiratory or
metabolic in nature. -If pH and PCO2 are moving in opposite
directions, then it is the pCO2 levels that are causing the
imbalance and it is respiratory in nature.
, 4 | Page
-If PCO2 is normal or is moving in the same direction as the
pH, then the imbalance is metabolic in nature.
The anion gap is the difference between measured cations
(Na+ and K+) and measured anions (Cl- and HCO3-), this
calculation can be useful in determining the cause of metabolic
acidosis.
Why would an increased anion gap be observed in diabetic
ketoacidosis or lactic acidosis? - correct answer- The anion gap
is the calculation of unmeasured anions in the blood.
Lactic acid and ketones both lead to the production of
unmeasured anions, which remove HCO3- (a measured anion)
due to buffering of the excess H+ and therefore leads to an
increase in the AG.
Why is it important to maintain a homeostatic balance of
glucose in the blood (ie describe the pathogenesis of
diabetes)? - correct answer- Insulin is the hormone responsible
for initiating the uptake of glucose by the cells. Cells use
glucose to produce energy (ATP).
In a normal individual, when blood glucose increases, the
pancreas is signaled to produced in insulin, which binds to
insulin receptors on a cells surface and initiates the uptake of
glucose.
