Exam 5 General

Question 1

What parts of the nephron reabsorb Na+?

Answer 1

• proximal tubule
• TAL
• early distal tubule
• late distal tubule
• cortical collecting duct

Question 2

What parts of the nephron reabsorb water? Which parts are regulated?

Answer 2

Unregulated: proximal tubule

Regulated: tDL, late distal tubule, cortical collecting duct

Question 3

Which side of the cells use active transport to move Na+?

Answer 3

basolateral

-to maintain conc gradient needed for passive or secondary active transport along apical membrane

Question 4

SGLT2 transporters are on what side of the cell and at what end of the proximal tubule?

Answer 4

• apical side (secondary active transport)

- early to middle

Question 5

SGLT1 transporters are on what side of the cell and at what end of the proximal tubule?

Answer 5

• apical side (secondary active transport)

- middle to late

Question 6

GLUT2 transporters are on what side of the cell and at what end of the proximal tubule?

Answer 6

• basolateral (facilitated diffusion)

- early to middle

Question 7

GLUT1 transporters are on what side of the cell and at what end of the proximal tubule?

Answer 7

• basolateral (facilitated diffusion)

- middle to late

Question 8

What three parts of the nephron are the only places that are permeable to urea? Which direction does it go?

Answer 8

Urea secreted: tDL, tAL

Urea Reabsorbed: MCD

Question 9

Effects of Aldosterone?

Answer 9

LDT and CD

• increase Na+ reabsorption
• increase K+ secretion
• increases H+ secretion (Conn’s synd can cause alkylosis)

-incr Na+ reabsorption in sweat/salivary glands and colon and K+ secretion in sweat/salivary glands

Question 10

What increases aldosterone secretion?

Answer 10

• increased plasma K+
• Angiotensin II (RAAS)

-changes associated with Na+ or volume depletion or low blood pressure.

Question 11

What decreases aldosterone secretion?

Answer 11

• ANP (they have opposing goals)
• hypernatremia (weak control)

-changes associated with increased Na+ and volume or high blood pressure

Question 12

Effects of angiotensin II?

Answer 12

• increased Na+ and water reabsorption

- stimulates aldosterone secretion

Question 13

What stimulates angiotensin II secretion?

Answer 13

• decreased MAP

- decreased ECF volume

Question 14

How does angiotensin II work?

Answer 14

EVERYWHERE BUT tDL (only water reab there)

• increases Na+/H+ antiporter on apical membrane
• increases Na+/K+ antiporter and Na+/HCO3- symporter on basolateral membrane
• enhances PT capillary reabsorption by: constricts efferent arteriole which incr filtration fraction, so it decreases flow in PT capillaries and incr osmotic pressure of PT capillaries since FF incr.

Question 15

Where in the nephron does angiotensin work?

Answer 15

throughout

Question 16

Effects of ADH?

Answer 16

-increased water reabsorption from late distal tubule and collecting duct

Question 17

Mechanism of ADH

Answer 17

LDT and CD
-ADH activates the G-alpha-s protein linked receptor which then triggers phosphorylation of AQP-2 that sends them to the apical membrane. These aquaporins increase the permeability of H2O.

Question 18

What causes ADH secretion?

Answer 18

• decreased MAP

- increased ECF osmolarity

Question 19

Effects of ANP?

Answer 19

• increased GFR
• decreased Na+ reabsorption in proximal tubule
• decreased aldosterone (opposing)

Question 20

What stimulates ANP secretion?

Answer 20

increased BV stretches the atria which causes them to secrete ANP.

Question 21

Mechanism of ANP?

Answer 21

Proximal Tubule

• to increase GFR, it dilates the afferent arteriole and constricts the efferent arteriole
• to decrease Na+ reabsorption, it inhibits renin release and aldosterone formation