WGU D236 Pathophysiology Exam 2023 Questions and
Answers (Verified Answers)
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.
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, 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?
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
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
Describe the laboratory findings associated with metabolic acidosis, metabolic alkalosis,
respiratory acidosis and respiratory alkalosis. (ie relative pH and CO2 levels).
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 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?
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)?
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.
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.
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—electrolytes principally hyperkalemia;
I—ingestions or overdose of medications/drugs;
O—overload of fluid causing heart failure;
U—uremia leading to encephalitis/pericarditis
Compare and contrast hemodialysis and peritoneal dialysis.
What are some reasons for a patient choosing one over the other?
Hemodialysis uses a machine to pump blood from the body in one tube while dialysate
(made of water, electrolytes and salts) is pumped in the separate tube in the opposite
direction. Waste from the blood diffuses through the semipermeable membrane
separating the blood from the dialysate.
Peritoneal Dialysis does not use a machine, but instead injects a solution of water and
glucose into the abdominal cavity. The peritoneum acts as the membrane instead of
dialysis tubing. The waste products diffuse into the abdominal cavity and the waste
solution is then drained from the body.
Peritoneal dialysis offers continuous filtration and is less disruption to the patient's daily
routines. However, it does require some training of the patient and is not recommended
for individuals who are overweight or have severe kidney failure.
Hemodialysis provides medical care, but 3 times a week for several hours sitting at a
hospital or clinic. Individuals with acute kidney failure are recommended to use
hemodialysis.
How does homeostasis and maintaining optimal physiological health impact your
wellbeing?
Homeostasis acts to create a constant and stable environment in the body despite
internal and external changes. Proteins and other cellular processes require optimal
, conditions in order to carry out their functions.
Alterations in pH, salt concentration, temperature, glucose levels, etc. can have
negative effects on health, so it is vital for mechanisms that regulate homeostasis to
function properly for maintaining good health
Differentiate between Innate Immunity and Adaptive Immunity ?
The innate immune system encompasses physical barriers and chemical and cellular
defenses. Physical barriers protect the body from invasion. These include things like the
skin and eyelashes. Chemical barriers are defense mechanisms that can destroy
harmful agent. Examples include tears, mucous, and stomach acid.
Cellular defenses of the innate immune response are non-specific. These cellular
defenses identify pathogens and substances that are potentially dangerous and takes
steps to neutralize or destroy them.
Adaptive immunity is an organism's acquired immunity to a specific pathogen. As such,
it's also referred to as acquired immunity. Adaptive immunity is not immediate, nor does
it always last throughout an organism's entire lifespan, although it can.
The adaptive immune response is marked by clonal expansion of T and B lymphocytes,
releasing many antibody copies to neutralize or destroy their target antigen
What is a way that Adaptive Immunity can recruit innate immunity?
The innate immune response to microbes stimulates adaptive immune responses and
influences the nature of the adaptive responses.
Conversely, adaptive immune responses often work by enhancing the protective
mechanisms of innate immunity, making them more capable of effectively combating
pathogenic microbes
Why are some infections harder on children while other infections are harder on the
elderly?
Children have not been exposed to many pathogens yet, so they lack memory cells and
have not built-up immunity yet.
The elderly have a depleted naïve T cell population from years of battling infections, so
the likelihood of getting a match is less.
Describe how and why our injury response results in the signs of redness, swelling,
heat, and pain?
(Be sure to use chemokines, histamine, and vasodilation in your response.)
An injury causes an inflammatory response which is responsible for the redness,
swelling, heat and pain. Upon injury, cells on the surface begin to release chemokines
which act as messengers that something has happened.
Mast cells are also alerted to release histamines which travel to the endothelial cells of
capillaries and causes vasodilation, which is related to swelling and redness.
Answers (Verified Answers)
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.
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, 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?
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
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
Describe the laboratory findings associated with metabolic acidosis, metabolic alkalosis,
respiratory acidosis and respiratory alkalosis. (ie relative pH and CO2 levels).
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 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?
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)?
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.
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.
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—electrolytes principally hyperkalemia;
I—ingestions or overdose of medications/drugs;
O—overload of fluid causing heart failure;
U—uremia leading to encephalitis/pericarditis
Compare and contrast hemodialysis and peritoneal dialysis.
What are some reasons for a patient choosing one over the other?
Hemodialysis uses a machine to pump blood from the body in one tube while dialysate
(made of water, electrolytes and salts) is pumped in the separate tube in the opposite
direction. Waste from the blood diffuses through the semipermeable membrane
separating the blood from the dialysate.
Peritoneal Dialysis does not use a machine, but instead injects a solution of water and
glucose into the abdominal cavity. The peritoneum acts as the membrane instead of
dialysis tubing. The waste products diffuse into the abdominal cavity and the waste
solution is then drained from the body.
Peritoneal dialysis offers continuous filtration and is less disruption to the patient's daily
routines. However, it does require some training of the patient and is not recommended
for individuals who are overweight or have severe kidney failure.
Hemodialysis provides medical care, but 3 times a week for several hours sitting at a
hospital or clinic. Individuals with acute kidney failure are recommended to use
hemodialysis.
How does homeostasis and maintaining optimal physiological health impact your
wellbeing?
Homeostasis acts to create a constant and stable environment in the body despite
internal and external changes. Proteins and other cellular processes require optimal
, conditions in order to carry out their functions.
Alterations in pH, salt concentration, temperature, glucose levels, etc. can have
negative effects on health, so it is vital for mechanisms that regulate homeostasis to
function properly for maintaining good health
Differentiate between Innate Immunity and Adaptive Immunity ?
The innate immune system encompasses physical barriers and chemical and cellular
defenses. Physical barriers protect the body from invasion. These include things like the
skin and eyelashes. Chemical barriers are defense mechanisms that can destroy
harmful agent. Examples include tears, mucous, and stomach acid.
Cellular defenses of the innate immune response are non-specific. These cellular
defenses identify pathogens and substances that are potentially dangerous and takes
steps to neutralize or destroy them.
Adaptive immunity is an organism's acquired immunity to a specific pathogen. As such,
it's also referred to as acquired immunity. Adaptive immunity is not immediate, nor does
it always last throughout an organism's entire lifespan, although it can.
The adaptive immune response is marked by clonal expansion of T and B lymphocytes,
releasing many antibody copies to neutralize or destroy their target antigen
What is a way that Adaptive Immunity can recruit innate immunity?
The innate immune response to microbes stimulates adaptive immune responses and
influences the nature of the adaptive responses.
Conversely, adaptive immune responses often work by enhancing the protective
mechanisms of innate immunity, making them more capable of effectively combating
pathogenic microbes
Why are some infections harder on children while other infections are harder on the
elderly?
Children have not been exposed to many pathogens yet, so they lack memory cells and
have not built-up immunity yet.
The elderly have a depleted naïve T cell population from years of battling infections, so
the likelihood of getting a match is less.
Describe how and why our injury response results in the signs of redness, swelling,
heat, and pain?
(Be sure to use chemokines, histamine, and vasodilation in your response.)
An injury causes an inflammatory response which is responsible for the redness,
swelling, heat and pain. Upon injury, cells on the surface begin to release chemokines
which act as messengers that something has happened.
Mast cells are also alerted to release histamines which travel to the endothelial cells of
capillaries and causes vasodilation, which is related to swelling and redness.
