Lecture 11- Acid-base balance; Calcium

Question 1

pH values that cannot sustain life

Answer 1

less than 6.8

more than 7.8

Question 2

2 forms of acids

Answer 2

volatile and nonvolatile

Question 3

… acids are by-products of metabolism that can be exhaled or dissipated by the lungs

Answer 3

volatile

CO2 is one beacuse it produces H+ in the water of body fluids

Question 4

…. acids arise from metabolism or the diet; examples are phosphoric, lactic, sulfuric acids and ketones

Answer 4

nonvolatile

Question 5

nonvolatile acids must be neutralized by… and are regulated by the … system.

Answer 5

HCO3

renal

**neutralization requires continual replenishment of HCO3

Question 6

the lowest possible pH for urine is …. which represents very little free H+ and this pH is of the urine is not sufficient to excrete the nonvolatile acid load. therefore the kidney needs to excrete more acid than can be hel in a solution of this pH–> solution is buffers

Answer 6

4.4

Question 7

physiological buffers?

Answer 7

bicarbonate
phosphate
hgb
plasma proteins

Question 8

in addition to bicarbonate, the kidney uses … and … as buffers

Answer 8

phosphate (used 1st but supply is limited)

ammonium

Question 9

Net acid excretion (NAE) should remove all … acid in 3 components

Answer 9

nonvolatile

H+, HPO4-2, NH4+

Question 10

urine contains both titratable acids and …

Answer 10

NH4+

Question 11

what are the titratable acids in the urine?

Answer 11

H+

HPO4-

Question 12

kidney regulates acidity of the urine by regulating…. reabsorption

Answer 12

HCO3-

Question 13

3 options for renal regulation of body pH

Answer 13

1. decrease body pH by not reabsorbing all bicarb
2. no effect by reabsorbing all bicarb
3. increase body pH by reabsorbing all bicarb and making more bicarb

Question 14

bicarb reabsorption begins in the … and …% of filtered bicarb is reabsorbed here

Answer 14

proximal tubule

80%

Question 15

… = bicarb reabsorption

Answer 15

hydrogen secretion

Question 16

T/F bicarb is directly transported from tubular fluid into blood

Answer 16

false

Question 17

in the proximal tubule, … acitivity in the tubular epithelium produces … and …

… is secreted via … antiporter and … is reabsorbed across basolateral membrane

Answer 17

carbonic anhydrase
H+
HCO3-

H+
Na+/H+

HCO3-

Question 18

T/F no bicarb is reabsorbed in the thick ascending limb

Answer 18

false. some is and it is in the same manner as the proximal tubule

Question 19

production of NH4+ in the proximal tubules by metabolism of …
the NH4+ that is produced is transported into the tubular fluid and the HCO3- moves into the blood

Answer 19

glutamine

Question 20

production of NH4+ in the proximal tubule cells is regulated by …

Answer 20

systemic pH

Question 21

acidosis upregulates synthesis of enzymes for … metabolism but this takes time

Answer 21

glutamine

Question 22

more NH4+ can be added to urine by …

Answer 22

diffusion trapping

Question 23

much of the NH4+ leaving the proximal tubules is reabsorbed by the ….
NH4+ substitutes for K+ in the …. symporter and enters the interstitial fluid in the medulla where it is in equilibrium with NH3

Answer 23

ascending loop of henle

Na/K/2Cl

Question 24

because NH4+ is a polar molecule then it is … in the interstitial fluid but NH3 being …. can diffuse into the lumen of the collecting ducts

because there is excess H+ on the fluid, NH3 in lumen is …. to NH4+ and is once again … and gets eliminated in urine

Answer 24

“trapped”

nonpolar

protonated

“trapped”

Question 25

new bicarb can be produced in the …. by production of NH4+ from …

Answer 25

proximal tubule

glutamine

Question 26

diarrhea will cause gain or loss of H+?

Answer 26

gain H+ because bicarb lost

Question 27

vomiting will cause gain or loss of H+?

Answer 27

loss

Question 28

distribution of calcium
ICF
ECF
bone

Answer 28

1%
0.1%
99%

Question 29

how much of the calcium is free to be filtered?

Answer 29

about 1/2 of the 0.1% that is in the ECF

Question 30

hypocalcemia increases … of neural and mucle tissue ; tetany

Answer 30

excitability

Question 31

hypercalcemia can cause… and disorientation; can lead to death

Answer 31

cardiac arrythmias

Question 32

calcium is regulated by these 3 hormones

Answer 32

parathyroid hormone (PTH)

calcitriol (1,25 dihydroxyvitamin D)

calcitonin

Question 33

calcium is regulated by 3 hormones all of which are regulated by a…. found in plasma membrane of clls in parathyroid gland, thyroid parafollicular cells and cells of the proximal tubule

Answer 33

calcium sensing receptor (CaSR)

Question 34

… is released in response to hypocalcemia. it increases bone resorption, increases renal calcium reabsorption and stimulates calcitriol production

Answer 34

parathyroid hormone (PTH)

Question 35

… is released in response to hypercalcemia and increases bone deposition

Answer 35

calcitonin

Question 36

… stimulates actice transport of calcium into the small intestine

Answer 36

calcitriol (1,25 dihydroxyvitamin D)

Question 37

metabolism of vitamin D to calcitriol is stimulated by … and/or …

Answer 37

hypocalcemia

hypophosphatemia

Question 38

… facilitates PTH and increases renal reabsorption of calcium

Answer 38

calcitriol

Question 39

70% of calcium us reabsorbed in the proximal tubules mostly via …

Answer 39

paracellular transport (solvent drag)

Question 40

in the thick ascending limb, calcium is reabsorbed via…

Answer 40

transcellular and paracellular transport (not solvent drag)

Question 41

in the distal tubule, there is …. transport reabsorption of calcium and it can be regulated because expression of calcium transporters is regulated by ….

Answer 41

PTH

Question 42

T/F the collecting ducts have a significant role in calcium reabsorption

Answer 42

false