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Flashcards in Regulation of Renal Transport Deck (65)
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1

Urine pH range:

4.5-8.0 depending on diet

2

In what form are H+ ions secreted in the nephron?

Trap it in ammonia and phosphate ions

3

Early proximal convoluted tubule S1 cell H+ and HCO3- transport:

Apical: HCO3 -> CO2 + H2O (breaks it down CO2 and H20 diffuse across)
Basolateral: Na/HCO3- cotransporter

4

Late proximal convoluted tubule S3 cell H+ and HCO3- transport:

Apical: NHE and H+ ATPase pump
Basolateral: HCO3-/Cl- exchanger and Na/HCO3- cotransporter

5

TAL H+ and HCO3- transport:

Apical: NHE and H+ ATPase pump
Basolateral: HCO3-/Cl- exchanger

6

Alpha intercalated and medullary collecting-duct H+ and HCO3- transport:

Apical: NHE and H+ ATPase pump and K/H ATPase
Basolateral: Na/HCO3- cotransporter and HCO3-/Cl exchanger

7

What do alpha intercalated cells do?

Excrete H+ via H/K ATPase (K+ in H+ out) and H+ ATPase and reabsorb HCO3-

8

What do beta intercalated cells do?

Absorb H+ and secrete HCO3-

9

When urine is acidic what types of drugs tend to be reabsorbed?

Weak acid drugs

10

When urine is alkaline what types of drugs tend to be reabsorbed?

Weak basic drugs

11

What type of urine does meat cause?

Acidic urine

12

What food causes more basic urine?

Foods rich in carbohydrates

13

What affects does aldosterone have on Na+ transport?

Increase apical ENaC channel expression
Increase basolateral Na/K pump

14

Effect of guanylin peptides?

Diuresis: increase cGMP
decreased Na+ reabsorption by decreased K+, Na/K, N/H channels

15

Effect of prostaglandin/bradykinin?

Diuresis: decreased K+ and ENaC

16

Effects of dopamine?

Natriuresis: decreased NHE and Na/K

17

What is the neurohormonal gastrointestinal renal axis?

Fluid and solute intake in the gut cause release of gut-derived factors that affect the kidney

18

What are some neurohormones released from the gut?

Guanylin
Uroguanylin
Glucagon-like peptide 1 (GLP-1)

19

Agonists of guanylate cyclases in the kidney?

STa
GN
UGN

20

Two signaling pathways for guanylin peptides in proximal tubule?

GC-C: increased water secretion AQP-1 (diuresis)
cGMP dependent: decreased Na+ reabsorption (natriuresis)

21

Guanylin peptide signaling in principal cells of the CCD?

Activate phospholipase A2 to increase arachidonic acid concentration and inhibit Na+ channels and AQP 2, 3, 4

22

Where does dopamine cause diuresis?

PCT
TAL

23

PCT phosphate handling:

Apical: Na+/HPO4- and
H2PO4-/Na+ absorption via NaPi-IIa
Basolateral: not yet known

24

What does PTH cause?

Increased phosphate excretion
Decreased phosphate reabsorption

25

What does calcitonin cause?

Increased phosphate excretion
Decreased phosphate reabsorption

26

Two signaling pathways of PTH?

G-alphas: activates adenylyl cyclase -> cAMP -> PKA
G-alphaq: PLC -> PKA
both remove NaPi-IIa from apical membrane

27

ANP signaling pathway?

PKG activation to remove NaPi-IIa from apical membrane

28

Calcium reabsorption in proximal intestine?

Apical: calcium channels
Basolateral: Ca++ ATPase and Na/Ca antiporter exchanger

29

How are calcium intracellular levels kept under control?

Ca++ entering at the apical membrane will increase the microenvironments levels causing a binding of Ca++ to calbindins, as Ca++ is pumped out the basolateral membrane the microenvironment decreases in concentration causing a release of Ca++ from calbindin

30

Vitamin D effect?

Calcium absorption