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40 Cards in this Set
- Front
- Back
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What happens to the patient's weight if you add Na+?
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Nothing, but serum [Na]+ is increased
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How do you keep the osmolarity constant if you are a kidney?
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osmolarity too low - excrete water
osmolarity too high - retain or drink water |
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what does water loss stimualte in the brain?
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causes high osmolarity which is registered by sensors in the hypothalamus, and a signal is sent to the pituitary to secrete ADH
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What does the statement, "The hypothalamus will sacrifice tonicity for volume" mean?
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ADH is secreted in response to both high osmolarity AND low volume status; and ultimately, the brain chooses volume
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What is pathologic secretion of ADH called? Where is it seen?
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Syndrome of inappropriate ADH (SIADH); seen in lung cancer and post brain-trauma;
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How much water in a day can you drink without messing up your kidneys?
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20 L
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What is evolemic hyponatremia?
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sodium concentration in the blood is lower than normal; but volume is OK
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What is central diabetes insipidus, and what are its causes?
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no ADH is secreted; caused by brain trauma, pituitary tumors
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What is nephrogenic diabetes insipidus?
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when the kidney receptors don't respond to ADH; caused by lithium toxicity
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What does dehydration mean regarding the concentration of osmoles?
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concentration of osmoles is too high
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The (concentration/amount) of sodium reflects water status, while the (concentration/amount) of sodium dictates volume status.
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The CONCENTRATION of sodium reflects water status while the AMOUNT of sodium dictates volume status
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In a marathon runner who didn't drink anything during the race, what will be his sodium concentration in the blood? his blood pressure?
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sodium concentration in the blood - high (b/c of water loss)
blood pressure - low (b/c of sodium loss) |
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If a marathon runner who didn't drink anything during the race is given 5L of normal saline, what will be his sodium concentration in the blood? his blood pressure?
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sodium concentration
- high (b/c of added saline) blood pressure - normal (b/c of added saline) |
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If a marathon runner forces himself to drin 1L of water for every 1/2 mile he runs, what is his sodium concentration at the end of the run? His blood pressure?
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sodium concentration
- low (b/c water is added) blood pressure - low (b/c salt is depleted) |
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What is "shift" like in sodium?
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not enough to worry about
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What is typical daily input of sodium in the US?
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3450 mg
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Why would your body want to get rid of sodium, because your blood is too salty?
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no, for some reason evolution has decided that the more appropriate response to this is to drink. It is rather because the ECV is too high, which puts strain on the heart.
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Where are volume sensors outside of the kidney?
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LV and pulmonary vasculature
Atria Carotid sinus Aortic arch |
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What is the Juxtaglomerular Apparatus (JGA) comprised of?
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1. macula densa
2. extraglomerular mesangium 3. justaglomerular cells |
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What are the macula densa?
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specialized cells in the TAL where the TAL meets the mesangium; sensitive to [NaCl] and release COX2; increases renin release
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What are Juxtaglomerular cells? Where are they?
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renin secreting cells, in the terminal portion of the afferent arteriole
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What are 3 triggers for the JGA?
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1. change in renal perfusion pressure is sensed by the macula densa
2. change in solute delivery is also sensed by the macula densa 3. renal sympathetic outflow (activation of B adrenoreceptors triggers renin release) |
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What does Angiotension 2 cause immediatelY?
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Vasoconstriction and thirst, it also releases ALdosterone
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What blocks renin?
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Beta blockers
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What blocks Angiotensin II?
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ACE Inhibitors
Angiotension Receptor Blockers (ARBs) |
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What blocks Aldosterone?
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Aldosterone antagonists
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What hormones are responsible for increased sodium excretion by the kidney after volume expansion?
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atrial natriuretic peptide (ANP)
brain natriuertic peptide (BNP) |
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What hormone is responsible for increased sodium retention by the kidney after volume depletion?
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aldosterone
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If you have a patient with hyperaldosterone, what might you respect with regard to sodium balance? sodium concentration? blood pressure? potassium?
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sodium balance- too high (not enough output)
sodium concentration- normal (this is determined by water) blood pressure- high potassium- low, because aldosterone exchanges K for Na in the collecting ducts |
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A 28 year old woman comes into your office with a 2 day history of nausea, vomiting, and diarrhea. The patient believes the worst is over, but she still doesn't feel great. What might you expect with regard to sodium balance? sodium concentration? blood pressure?
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sodium balance-low
sodium concentration-don't know how much water she has been drinking blood pressure-low |
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What foods contain high levels of potassium? (5)
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oranges
bananas potatoes tomatoes tahitian Noni juice |
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What is most important with regard to K, input, output, or shift?
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shift
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What do you need to adequately excrete K via the kidneys? (3)
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1. GFR
2. Urine flow 3. Aldosterone |
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What does high urine flow do to potassium excretion?
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favors potassium excretion
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What helps SHIFT into cells? (4)
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1. insulin
2. beta-agonists (albuterol) 3. bases 4. hypo-osmolarity |
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What helps SHIFT out of cells? (4)
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1. insulinopenia (NPO)
2. acids 3. hyperosmolarity (acute) 4. cell rupture (rhabdomylosis, hemolysis) |
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What is rhabdomylosis?
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damanged muscle tissue breakdown
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How do you treat hyperkalemia?
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1. stabilize cardiac cell membranes (calcium)
2. SHIFT potassium back into cells 3. get it OUT (furosemide) |
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What is sodium excretion primarily regulated by?
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aldosterone and the sympathetic nervous system
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What is potassium excretion primary regulated by?
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aldosterone, but more by intracellular vs extracellular SHIFT
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