RAAS & Renal Elimination

Question 1

renin

Answer 1

released by kidneys in response to decreased blood volume, low BP, low Na+ (low oncotic pressure)

Question 2

Angiotensin I is converted to AG II in the ___ by ___

Answer 2

in the lungs by angiotensin converting enzyme (ACE)

Question 3

Angiotensin II

Answer 3

• powerful vasoconstrictor : raises BP by causing peripheral arterioles to constrict
• stimulates aldosterone secretion from adrenal cortex: increases reabsorption of NaCl & H2O by kidneys
• Net effect = higher blood pressure, increased fluid in vascular system
• system is self regulating

Question 4

when the heart muscle deteriorates + perfusion to the kidneys deteriorate = volume overload.
(low amount of perfusion pressure to kidney aka pt with CHF)

Answer 4

Effective Circulating volume (ECV)

Question 5

explain ECV

Answer 5

pt with CHF because pump that is supposed to be moving volume around body is only functioning at 20-30% (pump failure).

• then turn on RAAS, which increases fluid volume inside vasculature –> putting more fluid on pump that is already failing.
• pump is unable to push anymore fluid & actually begins to push less due to increased resistance = the patients HF worsens

Question 6

Treatment for ECV

Answer 6

diurese the patient & remove fluid - allowing them to get blood around to the kidney

Question 7

under the influence of aldosterone ; urine can contain 40gm to almost none per day

Answer 7

sodium

Question 8

kidney is major site for excretion; renal failure or lack of aldosterone rapidly lead to toxic levels of this ion in the blood

Answer 8

potassium

Question 9

• end product of protein metabolism
• it is filtered in the glomerulus then reabsorbed in the tubule.
• the longer the tubular fluid sits in the tubule, the more of this that is absorbed leading to increased BUN

Answer 9

urea

Question 10

dehydration causes increased levels of

Answer 10

BUN

Question 11

what will happen to BUN levels if the patient eats a high protein diet? what if they have a GI bleed?

Answer 11

high protein diet = BUN increases

GI bleed - BUN increases then too because essentially your body is digesting a big protein load from the blood and the kidneys only have a max amount it can filter out.

Question 12

high or low levels of this ion precipitate cardiac dysrhythmias and lead to cardiac toxicity

Answer 12

potassium

Question 13

product of purine metabolism which can cause gout if blood levels are high & renal calculi if filtrate [ ] are high

Answer 13

uric acid

Question 14

changing the pH of the urine can vastly increase or decrease the elimination of a ___

Answer 14

drug

is sometimes used to facilitate excretion of a toxic dose.