WGU PATHOPHYSIOLOGY D236 2022-2023
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1. What is Starling's Law
of Capillary
forces?
How does this
explain why a
nutritionally deficient child
... [Show More] would
have edema?
2. How does the
RAAS
(Renin-Angiotensin-Aldosterone System)
result in
increased blood
volume and
increased blood
pressure?
3. How can hyperkalemia lead to
cardiac arrest?
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.
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.
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 impuls-
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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
5. Describe the laboratory findings
associated with
metabolic acidosis, metabolic alkalosis, respiratory acidosis and
respiratory alkalosis. (ie relative
pH and CO2 levels).
es 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
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
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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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 orlactic acidosis?
7. Why is it important to maintain a homeostatic balance of glucose in the blood
(ie describe the
pathogenesis of
diabetes)?
-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 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. [Show Less]