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82 Cards in this Set
- Front
- Back
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How much water is taken in daily on average? |
2500 mL/day |
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How much water is lost through insensible loss (skin, lungs)? |
700 mL/day |
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How much water is lost through sweat and feces daily? |
300 mL/day |
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How much water is lost through urine daily? |
1500 mL/day |
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What is the osmolality of urine during diuresis? |
50-75 mOsm/kg |
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What is the maximum output of urine during diuresis? |
20-25 L/day |
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What is the minimum output of urine during antidiuresis? |
0.5 L/day |
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What is the osmolality of urine during antidiuresis? |
1200-1400 mOsm/kg |
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What's another term for ADH? |
arginine vasopressin (AVP) |
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What two sense receptors determine necessity for water-reabsorption via ADH? |
- hypothalamic osmoreceptors - volume receptors (baroceptors) |
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Between osmoreceptors and baroceptors, which is more sensitive to change and thus more likely to lead to ADH regulation? |
Osmoreceptors |
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How does blood volume affect the sensitivity of osmolarity on ADH secretion? |
The more blood volume, the less sensitive the osmoreceptors; the less blood volume, the more sensitive the osmoreceptors. |
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What happens to urine osmolarity as ADH in blood increases? |
Urine osmolarity increases |
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Besides water reabsorption in the distal nephron, how else does ADH increase total body water? |
Stimulates thirst |
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How high are ADH levels in SIADH? |
Very high (hence the name Syndrome of Inappropriate ADH) |
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What are some causes of SIADH? (5) |
- head trauma - encephalitis - meningitis - ADH-secreting tumors (lung or pancreas) - Drugs |
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What kind of drugs can induce SIADH? (3) |
- nicotine - morphine - chemo |
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What effect does SIADH have on serum sodium concentration? |
Decreases serum sodium (hyponatremia) |
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What can a large drop in serum sodium cause? |
Coma |
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What are ADH levels in a patient with diabetes insipidus? |
Too low |
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Describe the 2 types of diabetes insipidus. |
1) Hypothalamic D.I. - not produced or released
2) Nephrogenic D.I. - binding is reduced, so water cannot be reabsorbed |
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What drugs can cause secondary diabetes insipidus? (2) |
lithium, tetracyclines |
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Deficit of which ion can lead to decreased activity of ADH? |
Potassium (Hypokalemia) |
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What effect does diabetes insipidus have on serum sodium levels? |
increases serum sodium (hypernatremia) |
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What drug is essentially synthetic ADH? |
DDAVP (Desmopressin nasal spray) |
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What is the corrective treatment for primary D.I.?
Secondary? |
Primary - DDAVP nasal spray
Secondary - drink 20L water daily |
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What value assesses how efficiently the ascending limb of the Loop of Henle is at reabsorbing sodium chloride? |
Free Water Clearance (FWC) |
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How is FWC calculated? |
FWC = V - ((VxU)/P) |
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What caveat must be true before measuring FWC? |
Patient must have no ADH circulating. |
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How is a patient prepared for FWC measure? (2) |
- Water loading - ADH receptor antagonists |
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What effect do loop diuretics have on free water clearance? |
Decrease it bc water reabsorption is down |
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When is FWC equal to zero? |
When urine is isotonic to serum |
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How are changes to extracellular volume as a result of sodium ingestion compensated? |
NaCl excretion |
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What is the only segment of the nephron that aldosterone acts on? |
Cortical collecting tubule |
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What percentage of NaCl regulation is controlled in the cortical collecting tubule? |
5% |
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In what 3 ways does aldosterone increase sodium reabsorption? |
1) Increases number of luminal Na channels 2) Increases Na/K ATPase synthesis 3) Increases Krebs cycle enzyme for ATP |
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Will a change in total sodium content be reflected in extracellular fluid? |
No, osmolarity is maintained |
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Does infusion of isotonic saline affect the sodium concentration in extracellular fluid?
Hemorrhage? |
No and no |
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How are total sodium changes sensed? |
Baroceptors to water volume |
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Where in the body are baroceptors located? (4) |
- Heart - lung - CV - kidney |
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Where in the heart and CV are baroceptors predominant? (3) |
- atria - carotid sinus - aortic arch |
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What specific part of the kidney has baroceptors? |
juxtaglomerular apparatus |
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What effect does high stimulation of baroceptors have on aldosterone?
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decreases it |
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What is the rate-limiting step of the RAAS system? |
Renin release |
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Is renin a hormone?
What does it do? |
No, enzyme
Converts Angiotensinogen to Angiotensin I |
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What organ makes angiotensinogen? |
liver |
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What enzyme converts Angiotensin I to Angiotensin II? |
converting enzyme (ACE) |
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Name a renin inhibitor. |
Aliskerin |
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Name an ACE inhibitor that is not Lisinopril. |
Captopril |
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Name two Angiotensin II receptor antagonists. |
Saralastin and Lorsartan |
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Name an aldosterone receptor antagonist. |
spironolactone |
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What cells in CV secrete renin? |
Granular cells in the afferent arteriole |
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In what 3 ways is renin secretion regulated? |
1) Intrarenal baroreceptors 2) Sympathetic nervous stimulation 3) Macula densa monitoring GFR |
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What effect does BP drop have on renin secretion? |
increases it |
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What affect does an increase in GFR have on renin secretion? |
reduces it |
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What are the rapid effects of Angiotensin II to help restore normal BP during hemorrhage? (3) |
- Increase heart rate - Increase stroke volume - Increase peripheral resistance (including afferent arteriole) |
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What part of the nephron has Angiotensin II receptors?
What effect does it have? |
PCT
increases reabsorption |
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What hormones does Angiotensin II stimulate the secretion of? (2) |
- Aldosterone - ADH |
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Why does urine sodium concentration rebound after days of sustained aldosterone release in blood? |
The increase in BP compensates for sustained aldosterone by pushing out more water and sodium into urine |
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What effect does atrial natriuretic peptide (ANP) have on serum sodium and water? |
reduces both by increasing their excretion |
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What effect does ANP have on the afferent arteriole? |
vasodilation |
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What effect does ANP have on renin? |
Inhibits renin release |
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On what part of the nephron does ANP act? (2) |
PCT and CT |
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What effect does ANP have on ADH? |
Antagonizes its release and CT effects |
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What neurotransmitter inhibits PCT reabsorption of NaCl? |
dopamine |
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Where does dopamine in the kidney come from? |
L-DOPA is taken up by PCT cells and converted to dopamine |
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What transport ion secretes DA? |
organic cation transporters |
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What does DA binding to D1 and D2 receptors lead to? (2) |
- Inhibition of Na/K ATPase - Inhibition of Na/H antiporter |
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What is another term for the Na/2Cl/K symporter?
How many types are there? |
Electro Neutral Sodium Chloride Co-transporter (ENCC)
3 |
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Where are each of the 3 ENCCs located? |
ENCC1 - DCT
ENCC2 - Thick ascending LoH
ENCC3 - papillary CT (basolateral) |
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What is Bartter's syndrome? |
Mutation in ENCC2 or ROMK (K-channel) leading to salt wasting |
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What are renin levels in Bartter's syndrome?
aldosterone?
calcium?
potassium? |
Renin - high
Aldosterone - high
Calcium - low
Potassium - low |
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What are the 2 genes associated with polycystic kidney disease? |
PKD1 and PKD |
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Which gene associated with polycystic kidney disease is autosomal dominant?
autosomal recessive? |
AD: PKD1
AR: PKD |
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Which gene defect associated with polycystic kidney disease results in infant mortality? |
ARPKD |
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What type of antidiuretic acts on the PCT?
Give an example. |
Carbonic anhydrase inhibitor
acetazolamide |
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What type of diuretics act on the Loop of Henle?
Give two examples |
Loop diuretics
Furosemide and Bumetanide |
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What type of diuretic acts on the DCT?
What transporter does it inhibit? |
Thiazide
luminal NaCl cotransporter |
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What diuretic acts on the CT?
Give two examples. |
Potassium-sparing diuretics
amiloride and spironolactone |
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What transporter does amiloride block? |
luminal Na-channel |
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What does spironolactone block? |
aldosterone receptor |
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What hormone does a decrease in effective circulating volume stimulate? |
Aldosterone |
