Gene Models & Nephron Function II Flashcards
What is the function of the loop of henle
urine concentration
What does the loop of henle reabsorb
Na+, Cl-, H2O, Ca2+, Mg2+
What drug targets the loop of henle
loop diuretics
Describe the important structures of the loop of henle
thin descending limb, thick ascending limb, thin ascending limb
Describe the permeability of the thin descending limb
water permeable, impermeable to sodium and chloride
Describe the permeability of the ascending limb
impermeable to water, permeable to sodium and chloride
Which side faces the tubular fluid
apical
Which side faces the blood
basolateral
What are the channels on the apical side of the TAL
ROMK, NKCC2
Describe sodium movement in the TAL
reabsorbed across the basolateral membrane
Describe chloride movement in the TAL
moves in through NKCC2, reabsorbed into blood through CLCK
What channels are located on the basolateral side of the TAL
sodium potassium ATPase, potassium channel, CLCK, barttin
What does CLCK allow
eflux of chloride across basolateral membrane
What does barttin allow
function of CLCK
What is the function of ROMK
recycle potassium from NKCC2 across apical membrane
What does NKCC2 require to function
potassium
What does the reabsorption of sodium and chloride drive
reabsorption of calcium and magnesium
How is Bartter’s inherited
recessively
What mutations in what can cause bartter’s
CLCK/barttin, NKCC2, ROMK
What do the mutations in bartter’s cause to function improperly
NKCC2
What is NOT reabsorbed in bartter’s
sodium and chloride
What are the symptoms of Bartter’s
salt wasting, polyuria, hypotension, hypokalaemia, metabolic alkalosis, hypercalciuria
What is hypokalaemia
low plasma potassium
What causes hypotension in Bartter’s
decreased ECF volume
What is hypercaliuria
high calcium in urine
What is ROMK knockout mouse a model for
Bartter’s syndrome
What is fractional excretion
amount in urine/amount filtered
What symptoms are exhibited by ROMK knockout mice
salt wasting, polyuria,
What symptoms of ROMK knockout mouse do not fit the model for Bartters
acidic plasma pH, hyperkalaemia
Why might the ROMK knockout mouse give the wrong symptoms for Bartter’s
complete los of function of ROMK rather than mutation
Name two loop diuretics
furosemide, bumetanide
What do loop diuretics treat
high blood pressure, excess fluid
What do loop diuretics block
NKCC2
What do loop diuretics inhibit
water, sodium and chloride reabsorption
What drug causes symptoms like Bartter’s
loop diuretics
What can carriers for bartter’s have protection from
hypertension
What is reabsorbed in the early distal tubule
sodium, chloride, magnesium
What drug targets the early distal tubule
thiazide diuretics
What channels are on the apical membrane of the early distal tubule
NCC, magnesium channel
What channels are located on the basolateral side of the early distal tubule
CLCK, barttin, potassium channel, sodium potassium ATPase
How is Gitelman’s inherited
recessively
What symptoms does Gitelman’s syndrome exhibit
salt wasting, polyuria, hypotension, hypokalaemia, metabolic alkalosis, hypocalciuria
What channel is mutated in Gitelman’s syndrome
NCC
What part of the nephron does Gitelman’s syndrome affect
distal tubule
What symptom is different between Bartter’s and Gitelman’s syndrome
hypocalciuria and hypercalciuria
What is the mutation of NCC in Gitelman’s syndrome most likely to be
trafficking mutation
Example of a thiazide diuretic
chlorothiazide
What channel does thiazide diuretics target
NCC
What does thiazide diuretics treat
high BP
What is the effect of thiazide diuretics on the body
reduce water reabsorption
What side effects can thiazide diuretics give you
side effects like gitelman’s syndrome
How are magnesium and chloride reabsorbed in the thick ascending limb
paracellularly
