Sweep 1.2

Question 1

K+ - sparing diuretics act where

Answer 1

K+ is normally secreted into the tubular fluid by the principal cells.

Question 2

K+ sparing

1. aldosterone antagonists,

Answer 2

e.g. spironolactone
block aldosterone’s ability to increase Na+ transporters in principal cells

must get inside tubular cells to block aldosterone receptors

Question 3

K+ sparing

2. ENaC blockers,

Answer 3

e.g. amiloride
block Na+ reabsorption across the apical membrane

these act on a membrane protein so can gain access by secretion into the proximal tubule

Question 4

Aquaretics, e.g. tolvaptan, increase excretion of

Answer 4

water by blocking the action of ADH in the late distal tubules and collecting duct. Water is eliminated without the loss of solutes.

Question 5

Diuretic braking phenomenon

Continued use of diuretics becomes

Answer 5

less effective because volume contraction counteracts the effects of the diuretic, i.e. diuretics decrease ECV so compensatory mechanisms activated

Question 6

1. increased sympathetic activity in response to reduced BP –> decrease —– —-> increase

Answer 6

GFR

PT reabsorption & increase renin

Question 7

Secondary effects of diuretics

2. decrease

Answer 7

natriuretic peptides

Question 8

Increased excretion of K+

Diuretics increase ——–, so they secondarily influence renal processing of other solutes (and water)

Answer 8

Na+ reabsorption

Question 9

K+ excretion increases because……

Answer 9

diurectics increase the flow of tubular fluid which stimulates K+ secretion

diuretics reduce ECV à increase aldosterone à stimulate K+ secretion

K+ -sparing diuretics are used to prevent an increase in K+ secretion

Question 10

Loop and thiazide diuretics —>

Answer 10

reduced ECV à metabolic alkalosis

Question 11

potassium-sparing diuretics —–> ———- because H+ secretion in distal tubule and cortical collecting duct is -=——

Answer 11

metabolic acidosis

inhibited

Question 12

Except for ———-, all other diuretics alter calcium excretion.

Answer 12

the K+ sparing diuretics

Question 13

Calcium reabsorption in the nephron

in proximal tubule –

Answer 13

mostly by paracellular transport/solvent drag

Question 14

Calcium reabsorption in the nephron

in thick ascending limb –

Answer 14

transcellular and paracellular transport (paracellular not solvent drag)

Question 15

Calcium reabsorption in the nephron

in distal tubule –

Answer 15

transcellular reabsorption of calcium

transport here can be regulated because expression of Ca2+ transporters is regulated by PTH

Question 16

Calcium reabsorption in the nephron

the collecting duct is not significantly involved with

Answer 16

Ca2+ reabsorption

Question 17

• calcitonin
released in response to ———-

increases ————

Answer 17

hypercalcaemia

bone deposition

Question 18

• calcitriol (1,25 dihydroxyvitamin D)

metabolism of vitamin D to calcitriol is stimulated by

Answer 18

hypocalcaemia and/or hypophosphatemia (and further stimulated by PTH, see above)

Question 19

• calcitriol (1,25 dihydroxyvitamin D)

stimulates active transport mechanism for

Answer 19

Ca2+ absorption in the small intestine

Question 20

• calcitriol (1,25 dihydroxyvitamin D)

facilitates action of ——- and increases ——

Answer 20

PTH

renal Ca2+ transport

Question 21

• parathyroid hormone (PTH)

released in response to

Answer 21

hypocalcaemia

Question 22

• parathyroid hormone (PTH)

increases ———–, increases renal —– reabsorption, and stimulates ——–

Answer 22

bone resorption

Ca+

calcitriol production

Question 23

Calcium is regulated by three hormones all of which are regulated by a

Answer 23

calcium sensing receptor (CaSR)

Question 24

Osmotic and CA inhibitors both act in ——— and reduce reabsorption of ————

Answer 24

proximal tubule

calcium in this segment (so excretion is increased).

Question 25

Loop diuretics increase calcium excretion by affecting the

Answer 25

transepithelial voltage that normally provides the driving force for paracellular transport of calcium.

Question 26

Thiazide diuretics stimulate

Answer 26

calcium reabsorption in the distal tubule and thus reduce excretion.

Question 27

Normally, distal tubule reabsorbs ---- of filtered calcium via active transport.

Answer 27

9%

Question 28

catheter – used to access

Answer 28

venous blood for short-term treatment; scarring, vessel narrowing or occlusion can occur

Question 29

AV fistula – preferred for

Answer 29

long-term treatment; creates an anastomosis between artery and vein. Arterial blood is withdrawn, and blood is returned to the vein after dialysis.

Question 30

AV graft – uses an

Answer 30

artificial/synthetic vessel to join an artery and vein when vascular problems do not permit using a fistula; can become narrowed which can lead to clotting and/or infections.

Question 31

Long-term consequences of hemodialysis

Answer 31

sepsis, endocarditis & osteomyelitis (secondary infections) amyloid deposits in joints (like amyloid plaques that form in neural tissue) can result from the build-up of trace minerals (e.g. copper, zinc, and aluminum) that might be in the dialysis fluid.

Question 32

Patients with chronic renal failure are almost always diagnosed with

Answer 32

anemia due inadequate secretion of erythropoietin (EPO) and loss of erythrocytes.

Question 33

EPO is produced by ------------ in the renal cortex, and its production is controlled at the transcriptional level.

Answer 33

interstitial fibroblasts

Question 34

HIFs are continually produced, but are targeted for degradation when

Answer 34

O2 is normal.

Question 35

HIFs | When O2 is low, they function as

Answer 35

transcription factors to increase EPO synthesis and secretion.

Question 36

EPO stimulates differentiation of --------- in the bone marrow

Answer 36

erythrocyte progenitor cells

Question 37

transcellular – molecules move

Answer 37

through tubular cells

Question 38

paracellular – molecules move

Answer 38

between tubular cells

Question 39

solvent drag results from solutes being carried by water in

Answer 39

paracellular transport

Question 40

rate of water diffusion can be regulated by

Answer 40

aquaporins

Question 41

Note that a decrease in plasma pH will increase the amount of ---------- which can be filtered and excreted, so alkalosis can lead to ----------.

Answer 41

free Ca2+ hypocalcemia

Question 42

Why is it important to regulate calcium? | hypocalcemia increases

Answer 42

excitability of neural and muscle tissue; tetany

Question 43

Why is it important to regulate calcium? | hypercalcemia can cause

Answer 43

cardiac arrhythmia and disorientation; can lead to death

Question 44

only a little more than ½ of ECF calcium is

Answer 44

free or complexed with anions, and, therefore, can be filtered in the glomerulus

Question 45

Metabolic alkalosis – hi

Answer 45

pH due to excess HCO3-

Question 46

Metabolic alkalosis | respiratory compensatory response –

Answer 46

hypoventilate (how does this work?) – increase CO2, increase CA reaction, increase acidity

Question 47

Metabolic alkalosis | renal compensatory response --->

Answer 47

excrete HCO3-

Question 48

Metabolic acidosis - low pH due to low

Answer 48

HCO3-

Question 49

Metabolic acidosis | causes include

Answer 49

diabetic ketosis, diarrhea, renal failure

Question 50

Metabolic acidosis | respiratory compensatory response ---->

Answer 50

hyperventilate

Question 51

Metabolic acidosis | renal compensatory response ---> produce

Answer 51

new HCO3-