W WGU D236 PATHOPHYSIOLOGY
WGU D236 PATHOPHYSIOLOGY EXAM LATEST 2024
QUESTIONS AND ANSWERS GRADED A+
1. What is Starling's Law of Capillary forces? How does this
explain why a nutritionally deficient child would have
edema?
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.
2. How does the RAAS (Renin-Angiotensin-
Aldosterone System) result in increased blood volume
and increased blood pressure?
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,
,W WGU D236 PATHOPHYSIOLOGY
which acts to increase sodium and water reabsorption increasing blood
volume, while also increased potassium secretion in urine.
3. How can hyperkalemia lead to cardiac arrest?
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.
4. 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?
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.
5. Describe the laboratory findings associated with
metabolic
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,W WGU D236 PATHOPHYSIOLOGY
acidosis, metabolic alkalosis, respiratory acidosis and
respiratory alkalosis. (ie relative pH and CO2 levels).
, W WGU D236 PATHOPHYSIOLOGY
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. -If PCO2 is normal or is moving
tin the same direction as the pH, then the imbalance is metabolic in nature.
6. 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?
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.
7. Why is it important to maintain a homeostatic balance
of glucose in the blood (ie describe the pathogenesis of
diabetes)?
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. Glucose is a very reactive molecule and if left
in the blood, it can start to bind to other proteins and lipids, which can lead to
loss of function. AGEs are advanced glycation end products that are a result
of glucose reacting with the endothelial lining, which can lead to damage in
the heart and kidneys.
8. Compare and contrast Type I and Type II Diabetes
Type I diabetes is caused by lack of insulin. With out insulin
signaling, glucose will not be taken into the cell and leads to high blood
glucose (hyperglycemia). Type I is usually treated with insulin injections.
Type II diabetes is caused by a desensitization to insulin signaling. The
insulin receptors are no longer responding to insulin, which also leads to
hyperglycemia. Type II is usually treated with drugs to increase the
sensitization to insulin (metformin), dietary and life-style changes or
insulin injections.
9. Describe some reasons for a patient needing dialysis AEIOU-
acidosis. Electrolytes, Intoxication/Ingestion, overload, uremia. Patients
with kidney or heart failure. A build up of phosphates, urea and
magnesium are removed
from the blood using a semi-permeable membrane and dialysate. AEIOU:
A— acidosis; E
WGU D236 PATHOPHYSIOLOGY EXAM LATEST 2024
QUESTIONS AND ANSWERS GRADED A+
1. What is Starling's Law of Capillary forces? How does this
explain why a nutritionally deficient child would have
edema?
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.
2. How does the RAAS (Renin-Angiotensin-
Aldosterone System) result in increased blood volume
and increased blood pressure?
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,
,W WGU D236 PATHOPHYSIOLOGY
which acts to increase sodium and water reabsorption increasing blood
volume, while also increased potassium secretion in urine.
3. How can hyperkalemia lead to cardiac arrest?
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.
4. 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?
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.
5. Describe the laboratory findings associated with
metabolic
Want to earn $103 per month?
,W WGU D236 PATHOPHYSIOLOGY
acidosis, metabolic alkalosis, respiratory acidosis and
respiratory alkalosis. (ie relative pH and CO2 levels).
, W WGU D236 PATHOPHYSIOLOGY
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. -If PCO2 is normal or is moving
tin the same direction as the pH, then the imbalance is metabolic in nature.
6. 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?
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.
7. Why is it important to maintain a homeostatic balance
of glucose in the blood (ie describe the pathogenesis of
diabetes)?
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. Glucose is a very reactive molecule and if left
in the blood, it can start to bind to other proteins and lipids, which can lead to
loss of function. AGEs are advanced glycation end products that are a result
of glucose reacting with the endothelial lining, which can lead to damage in
the heart and kidneys.
8. Compare and contrast Type I and Type II Diabetes
Type I diabetes is caused by lack of insulin. With out insulin
signaling, glucose will not be taken into the cell and leads to high blood
glucose (hyperglycemia). Type I is usually treated with insulin injections.
Type II diabetes is caused by a desensitization to insulin signaling. The
insulin receptors are no longer responding to insulin, which also leads to
hyperglycemia. Type II is usually treated with drugs to increase the
sensitization to insulin (metformin), dietary and life-style changes or
insulin injections.
9. Describe some reasons for a patient needing dialysis AEIOU-
acidosis. Electrolytes, Intoxication/Ingestion, overload, uremia. Patients
with kidney or heart failure. A build up of phosphates, urea and
magnesium are removed
from the blood using a semi-permeable membrane and dialysate. AEIOU:
A— acidosis; E
