WGU pathophysiology D236 study guide
Certification Exam answers verified
What is Starling's Law of Capillary forces?
How does this explain why a
... [Show More] 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 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
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. [Show Less]