Renal II

Question 1

why do we lose more K than Na

Answer 1

be the kidney has to exchange K to reabsorb Na and then try to recapture K

Question 2

Where urea goes ____ also goes

Answer 2

water

Question 3

without reabsorption how fast would we die?

Answer 3

2 hr

Question 4

what drugs build up in patients with AKI or CKD?

Answer 4

morphine and pancuronium

bc they are cleared by kidney

Question 5

where are drugs secreted on the nephron?

Answer 5

proximal tubule

Question 6

is there only 1 nephron per collecting duct?

Answer 6

no multiple nephrons attach to one collecting duct

Question 7

what does glomerulotubular balance accomplish?

Answer 7

minimizes the change in urine volume to prevent washout at increased GFR

Question 8

how does high GFR stimulate more reabsorption

Answer 8

high GFR increased peritubular capillary oncotic pressure,

draws water towards it

Question 9

what percent of the filtrate is always reabsorbed in the proximal tubule regardless of GFR?

Answer 9

67% of the filtrate

prevents large swings in urine volume and washout of the ECFV

Question 10

what transporter is more important for Na and water reabsorb?

Answer 10

Na/K ATPase

between at PT interstitium side

Question 11

how powerful are carbonic anhydrase inhibitors?

Answer 11

moderately

Question 12

high distal flow rate = more or less K secretion?

Answer 12

more

Question 13

tubular fluid/plasma concentration = 1

Answer 13

no reabsorption or secretion has occured in PT
OR
reabsorption of water has occurred at same rate in PT (Na)

Question 14

tubular fluid/plasma concentration <1

Answer 14

more substance has been reabsorbed than water in the PT

AA, Glu, HCO3-

Question 15

tubular fluid/plasma concentration >1

Answer 15

less substance has been reabsorbed than water in the PT

creatinine, urea, Cl

Question 16

transport maximum (Tm or Tmax)

Answer 16

point at which increases in concentration of substance do not result in increase movement of substance across cell membrane
(it will not be reabsorbed thus excreted)

Question 17

what is Tm determined by

Answer 17

saturation of limited number of transporters

Question 18

filtered load equation

Answer 18

filtered load= P[conc] * GFR

Question 19

do kidneys normally regulate plasma glucose?

Answer 19

NO

Question 20

what is the main job/transporters in the descending LOH

Answer 20

concentrating segment
from 300- 600/1200
reabsorbs water AQP channels (regardless of ADH)
reabsorb/secrete urea

Question 21

what do animals that survive in the desert have?

Answer 21

longer loops of henle

Question 22

what does ADH do in the thick ascending limb of LOH

Answer 22

increase NKCC2 activity

Question 23

what do you lose with Loop diuretics?

Answer 23

K and Calcium

VERY POWERFUL

Question 24

what percent of reabsorb happens in proximal tubule

Answer 24

67%

Question 25

what percent of reabsorb happens in thick ascending limb LOH

Answer 25

25%

Question 26

what percent of reabsorb happens in distal tubule?

Answer 26

5%

Question 27

what percent of reaborp happens in the distal cortical tubule/cortical collecting duct?

Answer 27

3%

Question 28

do carbonic anhydrase inhibitors have a big effect in the thick ascending limb?

Answer 28

no bc only 10% of H secr/bicarb reab happen here | compared to 80% in the PT

Question 29

what diuretics are preferred for loosing bone older women?

Answer 29

thiazide bc they lower intracellular Na and help increase Ca reabsor here

Question 30

what channel does Calcium go through in the distal tubule?

Answer 30

TRP channel

Question 31

what increases the expression of the TRP channel?

Answer 31

PTH | Vitamin D

Question 32

how does vitamin D help retain calcium

Answer 32

regulates calbindin that traps calcium inside of the cell and prevents excretion

Question 33

what are the two main things that happen in the distal cortical tubule/cortical collecting duct

Answer 33

3% Na reab | regulation of K, H/HCO3

Question 34

what does aldosterone do in the DCT/CCD?

Answer 34

increases ENaC, Na/K ATPase, K channel

Question 35

what does ADH do in the DCT/CCD?

Answer 35

increases ENaC, and AQP channels

Question 36

amiloride

Answer 36

blocks ENaC, potassium sparing moderately powerful

Question 37

two cell types in the DCT/CCD?

Answer 37

principal cells | type A intercalated cells

Question 38

what happens at the type A cell?

Answer 38

K reabsor | H secret

Question 39

when is H/K ATPase activity increased?

Answer 39

hypokalemia | leads to alkalosis

Question 40

what does AngII do in the PT?

Answer 40

stimulates NHE, Na/HCO3, and NaKATPase

Question 41

what does PTH and FGF23 inhibit in the PT?

Answer 41

Na/Pi inhibition

Question 42

what stimualtes the Na/Pi in the PT?

Answer 42

Vitamin D

Question 43

what are SGLT2 inhibitors for>

Answer 43

lower blood glucose in pts with type 2 diabetes

Question 44

what is the role of ADH

Answer 44

adjust the conc of medullary intersitium urinate or reabsorb water using urea HYPOtonic solution

Question 45

how can we obtain such a wide range of urine Volume and Osm?

Answer 45

high osmolarity of medullary fluids | regulation of H2O reabsorb by ADH

Question 46

what are the two countercurrent systems?

Answer 46

``` countercurrent multiplier (in LOH; creates gradient) countercurrent exchanger (in vein; preserves the gradient) ```

Question 47

what does ADH respond to?

Answer 47

changes in plasma Na | via thirst and water transport

Question 48

what does RAAS respond best to?

Answer 48

changes in plasma volume | increases Na and H2O reabsorb at same rate and increases volume

Question 49

what does dehydration do to plasma Na plasma Osmo Urine Osmo

Answer 49

Na- increase plasma Osmo- increase urine osmo- increase

Question 50

what does hypersecretion of ADH do to plasma Na plasma osmo urine osmo

Answer 50

Na- decrease plasma osmo- decrease urine osmo- increase

Question 51

what does diabetes insipidus (ADH deficient) do to plasma Na plasma osmo urine osmo

Answer 51

Na- increase plasma osmo- increase urine osmo- decrease

Question 52

what is RAAS opposed by?

Answer 52

ANP/BNP

Question 53

what is Reabsorption of Na controlled principally by?

Answer 53

RAAS bc it does not effect urea | ISOtonic volume

Question 54

what is the goal of ANP and BNP

Answer 54

oppose RAAS and lower ECFV via Na and water excretion

Question 55

what things increase Na excretion

Answer 55

ECF Na ECF volume natriuretic peptides (ANP/BNP)

Question 56

what things reduce Na excretion

Answer 56

``` RAAS ang II aldosterone sympathetic stimulation ADH ```

Question 57

what does elevated K stimulate?

Answer 57

aldosterone | helps to reabsorb Na and secretes K

Question 58

hypokalemia number

Answer 58

<3.5mM

Question 59

hyperkalemia number

Answer 59

>5.5mM

Question 60

what happens when plasma K is increased?

Answer 60

skeletal muscles increase K intake via Epi, aldosterone, insulin cascade THEN kidneys can rev up excretion

Question 61

what is the major osmotic portion of the ICF

Answer 61

K

Question 62

what is plasma K mostly regulated by?

Answer 62

skeletal muscle

Question 63

what things push you towards hyperkalemia?

Answer 63

hyperosmolarity exercise cell lysis acidosis

Question 64

what things push you towards hypokalemia?

Answer 64

insulin beta agonists aldosterone alkalosis

Question 65

what can aldosterone blockade lead to?

Answer 65

hyperkalemia

Question 66

what is the drive for K to leave the principal cell in the collecting duct?

Answer 66

50mV difference in charge (negative in the lumen) driving the gradient

Question 67

how does high flow increase K secretion?

Answer 67

``` bends cilia activates PKD1&2 and Ca entry activates ROMK increased K secretion ```

Question 68

what things decrease K secretion?

Answer 68

ang II | low potassium diet

Question 69

what things increase K secretion?

Answer 69

high Na delivery to principal cells aldosterone high plasma K high K diet