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N3366 PATHOPHYSIOLOGY ASSIGNMENTS 1, 2, 3 ANSWERS & RATIONALES
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N3366 PATHOPHYSIOLOGY ASSIGNMENTS 1, 2, 3 ANSWERS & RATIONALESN3366 PATHOPHYSIOLOGY ASSIGNMENTS 1, 2, 3 ANSWERS & RATIONALES
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ANSWERS & RATIONALES to ASSIGNMENT #2(Includes Alterations in Fluids & Electrolytes, Altered Cellular and Tissue Biology; Altered Cellular Proliferation)
Academic honesty reminder: It is ok to discuss the assignments with other students as a learning tool, but it is
considered a breach of academic honesty to copy answers directly from each other.
Also, when taking a test, do not have this or any other informational document visible.
Alterations in Fluids and Electrolytes
1. Remember the patient in Assignment #1, with cancer who can’t eat and has lost 80 pounds? Let’s add to his
assessment findings: let’s say he has generalized edema and a serum protein of 4gm/dl (normal = 6.0 to 8.3
gm/dl ). Which is the most accurate mini-concept map linking low protein with edema?
a. hypoproteinemia! concentration in blood is now lower than the normal concentration of fluids inside
cells! fluid goes from B to T.
b. hypoproteinemia! concentration in blood is now higher than the normal concentration of fluids inside
cells! fluid goes from B to T
c. hypoproteinemia! blood is now hyperosmolar compared to the cells ! fluid goes from T to B
d. hyperproteinemia!blood now has lower oncotic pressure than normal! fluid goes from T to B
2. All of the following are accurate possible findings in the patient above EXCEPT that
a. he has confusion due swollen brain cells.
b. he has crackles in his lungs from fluid in the alveoli (lung tissue).
c. his serum osmolality is 302 (norm = 280- 295).
d. he will need a hypertonic IV solution to return fluid status to normal.
Rationales for questions 1 & 2: After something has changed the concentration status of the blood, figure out
which has the higher concentration of solutes. Does blood (B) now have a higher concentration than tissue (T)? Or
does T now have a higher concentration than B? Fluids will always move by the principle of osmosis TOWARDS the
higher concentration, higher osmolality, higher tonicity, higher oncotic pressure, etc (all these terms have the same
PRINCIPLES driving them.) Remember: CONCENTRATION CALLS! and OSMOLALITY ORDERS!
In this question, proteins in the blood have diminished, so the blood has become LESS concentrated than normal, ie less
concentrated than the tissues, which INITIALLY are normal concentration. But when the CHANGED blood (now
HYPOproteinemic compared to the tissues NORMAL protein levels) gets to the tissue, an osmotic shift BEGINS. That shift
will be that fluid will be “called in” to the higher concentration—the TISSUE in this case. So with fluid going INTO the
tissues, you then develop edema, which explains the next question….“Swollen” brain cells means edema in the brain;
crackles in the lungs means edema in the lung tissue; a hypertonic IV is appropriate to help REVERSE edema (this
treatment will quickly change the blood concentration to hypertonicity --B more concentrated than T now—so that water
will COME OUT of cells).
So, C is the OUTLIER—remember, this is an EXCEPT question, so C, with its HIGH osmolality is the one that doesn’t fit
with the rest. Summary: A, B, D all fit with this scenario and C does not, so C is the answer.
3. A 28-year-old man presents with a low blood pressure due to blood loss from a gunshot wound. The regulatory
action that will best compensate for this patient’s fluid volume deficit is:
a. increased action of the natriuretic peptide system.
b. increased action of the RAAS.
c. inhibition of renin secretion.
d. conversion of aldosterone into angiotensin II.
4. As a result of the action in the previous question, all the following will occur EXCEPT:
a. the patient’s body will “hang on” to fluids.
b. Na+ will be retained by the kidneys.
c. water excretion into the urine will increase.
d. blood pressure will increase.
This study source was downloaded by 100000806176105 from CourseHero.com on 04-10-2022 01:39:12 GMT -05:00
https://www.coursehero.com/file/10467086/Answers-ASSIGNMENT-2/
, Rationale for 3 & 4: When there is a diminished blood volume (fluid volume DEFICIT) sensed by the kidneys, they
respond by secreting renin; renin stimulates the secretion of aldosterone from the adrenal cortex! aldosterone “tells” the
kidneys to hang on to Na by not excreting it in the urine & instead keeping it in the blood stream! when the kidneys
hang on to Na, H2O follow. As a result of hanging on to H2O in the body, urine output is DECREASED and blood volume
is INCREASED. Also, renin stimulates the process of angiotensin II creation; angiotensin II constricts blood vessels in the
periphery! blood volume that normally circulates out to peripheral vessels is decreased due to the constriction, so that a
larger part of the blood volume can be shunted to the central areas where it is most needed—heart, lungs, kidneys. So in
essence the main, most important circulatory areas have a compensatory increase in volume (and a much needed
increase in blood pressure), whereas the periphery gets a decrease (that’s why this patient probably has cool & pale
hands & feet). Answer 3A is wrong because the natriuretic system kicks in when the heart senses an excessive amount
of volume returning to it! atrial natriuretic peptide or b-type natriuretic peptide is secreted by the heart & the kidneys
respond by increasing urination, therefore reducing the fluid volume; a reduction in blood volume is NOT what this person
needs! Inhibition of renin secretion (3C) is the opposite of what is needed in this case. 3D is wrong because aldosterone
doesn’t convert into angiotensin II (be sure you know the basic steps of the RAAS).
The explanation above should answer the “why” of question 4. A,B,D are all applicable to this scenario. C is the outlier,
so it is the correct choice (As discussed above, part of the RAAS is to have aldosterone “tell” the kidneys to hang onto
Na+, thus ALSO hanging onto water—keeping it in the blood-- instead of excreting in the urine). PEARL OF WISDOM:
Any time you have a PROBLEM and then a COMPENSATION for the problem (just like when you are figuring out
acidosis/alkalosis & compensations), be sure you clearly separate them in your mind: “Here’s the problem and what
caused it. THEN here’s the body’s compensation for that problem. Or if you are given a scenario with the compensation,
be sure you can trace it back to the problem… that’s called studying from both the “front door” and the “back door.” See
the How-to” manual if you need more study tips like that.
(Normal labs: Na+ = 135 to 145; K+ = 3.5 – 5.0; osmo = 280- 295; HCO3 = 22-28).
5. A patient is hospitalized in renal failure. Because of her kidneys’ inability to excrete water, she has generalized
edema & a serum sodium of 129. Because the kidneys have also lost the ability to appropriately regulate
potassium, she also has a serum potassium of 5.9. These lab results show:
a. hypernatremia & hypokalemia.
b. hyperkalemia & hyponatremia.
c. hyperosmolality & hypernatremia.
d. hypoosmolality & hypocalcemia.
6. In the previous question, the edema is most likely due to fluid shifting from the intravascular space into interstitial
spaces secondary to all the following EXCEPT:
a. hypertonicity of the plasma space.
b. hypotonicity of the plasma space.
c. hypoosmolality of the blood.
d. diminished osmotic pressure of the blood.
Rationale for #5: Na levels < 135 = hyponatremia, or “low sodium in the blood,” and K levels > 4.5 = hyperkalemia, or “high
potassium in the blood.” Therefore answers A and C cannot be right, since they mention hypernatremia. And D is wrong because
nothing in the lab results that I gave you in the scenario relates to calcium, so hypocalcemia is not correct.
Pearl: Be sure to read your scenario thoroughly to understand what information you are given. But also don’t read anything MORE
into it.
Rationale for #6 In the beginning scenario you are told that the Na is low in the plasma space—serum Na of 129 (remember that the
plasma space is also called “the blood,” the “intravascular space,” the “vasculature,” the “vascular space,” and so forth), so you
already know that the patient is hyponatremic, which correlates with HYPOtonicity, not HYPERtonicity (answer B). When you are given
a scenario in which the patient has edema, always correlate this with FLUID VOLUME OVERLOAD—picture a patient who for some
reason (in this case “sick kidneys” which aren’t getting rid of H2O properly) has extra water in the blood, thus diluting it & decreasing
its concentration—this goes along with decreased osmolality (C) and diminished osmotic pressure (D). Thus B, C, D go together, and
will cause fluid to shift into the tissues, causing edema. [Remember, the tissues will initially be NORMAL in their osmolality & tonicity,
therefore, their concentration is now greater than that of the blood, so according to the rule – CONCENTRATION CALLS—the tissue
cells will pull water into them from the blood (“B to T”), causing edema.]
Answer A is the outlier in this EXCEPT question, thus it is the correct answer.
Pearl: Draw pictures!
Now, did you see the similarities in questions 1,2, 5, & 6? In one way or another they ALL resulted in LESS concentration in the blood,
thus the patient pictures were ultimately similar. Same thing with questions 7, 9-11, and some of the ones in question 14.
Think about their commonalities and then think about situations that would be the opposite.
This study source was downloaded by 100000806176105 from CourseHero.com on 04-10-2022 01:39:12 GMT -05:00
https://www.coursehero.com/file/10467086/Answers-ASSIGNMENT-2/
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