Exam 4 Condensed NEW Flashcards
How much glucose, amino acids, and carboxylates are reabsorbed in proximal tubule?
almost 100%
What 2 mechanisms auto-regulate renal function?
myogenic mechanism
tubuloglomerular feedback
What drives the reabsorption of Na+ in the early proximal tubule?
negative Vte
What is Liddle Syndrome?
increases ENac activity
causes more Na+ reabsorption and high BP
What is a loop diuretic?
inhibits Na/K/Cl co-transporter
targets thick ascending limb
What transporter reabsorbs NaCl in the distal tubule?
thiazide-sensitive NaCl co-transporter
Where is the most HCO3- reabsorbed?
proximal tubule
Fluid movement up the thick/thin ascending limb becomes more __________
diluted
What is special about principle cells in the distal tubule?
Na+ reabsorption stimulated by aldosterone
What transporter reabsorbs NaCl in thick ascending limb?
Na+/K+/Cl- co-transporter
What are the 2 fates of H+ secreted in the lumen?
- make new HCO3- (combines with OH- to make water)
- secreted as a titratable acid
What is the HCO3- pump and the H+ pump located on alpha-intercalated cells?
HCO3-: basolateral side
H+: apical side
What cell type performs HCO3- secretion in the distal tubule?
beta-intercalated cells (HCO3-/Cl- exchanger)
What 2 ions are mainly transported paracellularly in the thick ascending limb?
Mg2+
Ca2+
What 2 things are needed to make a concentrated urine?
- H2O permeable nephron segments
- hyper-osmotic medullary interstitum
What are 2 stimulators of ADH?
** 1. increased plasma osmolarity
2. decreased ECF
What transporter reabsorbs Na+ in principle cells of the collecting duct?
ENac
What is the osmotic equillibrium of the counter-current loop?
entering fluid is isosmotic but turns hyperosmotic as water is reabsorbed in tDLH
Increased filtration = increased tubule flow = ___________ reabsorption
increased reabsorption (increased osmotic pressure)
Where is most of the Ca2+ reabsorbed?
thick ascending limb
What is the single effect of the counter-current loop?
movement of NaCl out of ascending limb increases the osmolarity of interstitum
How does the thick ascending limb play a role in acid secretion?
Na+/HCO3- exchanger
- HCO3- reabsorption
What cell type performs H+ secretion in the collecting duct/distal tubule?
alpha-intercalated cells (H+/K+ pump)
What 3 segments of the nephron participate in acid secretion?
proximal tubule
thick ascending limb
cortical collecting duct
What is the role of ADH?
increase water reabsorption by inserting more aquaporins
What is the Vte of principle cells in the collecting ducts and why?
-40 mV
ENac is pulling Na+ out of lumen
How does the early proximal tubule play a role in acid secretion?
Na/HCO3- exchanger
- HCO3- reabsorption
H+ secretion
What’s the normal HCO3-?
24
What is the Vte of beta-intercalated cells in the collecting duct and why?
-40 mV
HCO3- is being pumped into lumen via HCO3-/Cl- exchanger
What is the Vte of the thick ascending limb and why?
+10 mV
lots of K+ channels pump K+ into lumen
How does auto-regulation of renal function via the tubuloglomerular feedback work?
single nephron senses increase in lumenal NaCl (at macula densa)
increased constriction of arterioles
decreased GFR/RBF
What is aldosterone’s affect on NaCl reabsorption?
increases
What are the 2 steps to generating a hyperosmotic medullary interstitum?
- reabsorb H2O in tDLH
- reabsorb NaCl in TAL
Does glutamine breakdown or urea formation make new HCO3-?
glutamine breakdown
What are the 2 factors that affect GT balance?
peritubular factors (change in starling forces)
luminal factors (tubule flow
What is Gitelman Syndrome?
defective thiazide-sensitive NaCl co-transporter
less NaCl reabsorption = more concentrated urine
0
0
What transporter do beta-intercalated cells use to transport Cl-?
HCO3-/Cl- exchanger
- aids in HCO3- secretion
What is the HCO3- pump and the H+ pump located on beta-intercalated cells?
HCO3-: apical side
H+: basolateral side
What cells are affected by ADH?
principle cells
What are 2 reasons kidneys excrete H+ into lumen?
reabsorb filtered HCO3-
excrete non-volatile acids
hat’s the role of the juxtaglomerular apparatus in kidney function?
contains masala dense and aids in tubuloglomerulus feedback (autoregulation)
What is the difference between Cl- transport in the early vs late proximal tubule?
early: only paracellular
late: trans and paracellular2
What nephron segment is referred to as the “reabsorbed”?
proximal tubule
What nephron segment “concentrates NaCl in the interstitum”?
loop of henle
What segment of the nephron “tightly regulates solute/H2O reabsorption”
DT and CD
What does the juxtaglomerulus release?
renin –> AT II
Does the early or late PT have more complex cells?
early
_____ reabsorption drives Cl- and H2O reabsorption in the PT
Na+
How much K+ is reabsorbed in the PT?
67%
How much Mg2+ is reabsorbed in the PT?
15%
How much Mg2+ is reabsorbed in the TAL?
70%
What part of the nephron contains the macala densa?
LH
What 2 sections of the nephron have complex cells?
PT
TAL
What section of the nephron has the most K+ channels on the apical side?
TAL
Why is Mg2+ reabsorption dominant over Ca2+ in the TAL?
paracellin-1
Does the DCT and CCT reabsorb both Na and Cl?
yes
Do alpha or beta-intercalated cells reabsorbed Cl- and NOT Na+?
beta intercalated
When ADH is present, does H2O permeability increase or decrease?
increase
What transporter on alpha-intercalated reabsorbs K+?
H/K pump
What is the HCO3- reabsorption channel in the TAL?
HCO3-/Cl-
What is the HCO3- reabsorption channel in the PT?
HCO3-/Na+
What is the H+ apical pump in the PT and TAL?
Na+/H+ pump
