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Flashcards in renal 3 Deck (96)
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1
Q

what is the normal pH range for the human body

A

7.35-745

2
Q

what is the nornmal HCO3 concentration of the body

A

24mM

3
Q

outside of what pH can life not be sustained

A

less than 6.8

greater than 7.8

4
Q

is it worse to be too basic or too acidic

A

too acidic, because body takes in more acid than base

5
Q

what are the two forms of acid in the body

A

Volatile acids

Nonvolatile acids

6
Q

what is a volatile acid

A

By-products of metabolism to be exhaled or dissipated by the lungs

7
Q

what is CO2 an acid

A

produces H in the water of body fluids

8
Q

what are nonvolatile acids

A

arise from metabolism of the diet

9
Q

what are examples of nonvolatile acids

A

Phosphoric acid
Lactic
Sulfuric acids
Ketones

10
Q

how can nonvolatile acids be neutralized

A

with HCO

11
Q

what regulates nonvolatile acids

A

REnal system

12
Q

what does neutralization of nonvolatile acids need

A

continual replenishment of HCO3

13
Q

how much acid should be found in the urin

A

the same as the nonvolatile acid load

14
Q

how does the kidney help in assuring that the amount of acid in the urine is equal to the nonvolatile acid load

A

reabsorbing all the filtered bicarbonate, then producing enough new bicarb to neutralize acids produced by the body

15
Q

what is the lowest possible pH for urine

A

4.4

16
Q

why is the lowest possible pH for urine 4.4

A

little free H, so not suffieicnet to excrete the nonvolatile acid load
- kidney must excrete more acid than can be held in solution (solid acid)

17
Q

what helps to ensure that the pH of urine never gets to low

A

Buffers binding to excess H to increase acid carried in urine without decreasing pH

18
Q

what acts as physiological buffers

A

HCO3
Phosphate
Ammonia
- all increase the amount of H excred

19
Q

what physiologic bugger is used first

A

Phosphate (endogenous)

20
Q

what is the action of Ammonium to serve as a buffer

A

Eliminates H and produces HCO3 that is reabsorbed

21
Q

where is ammonium produces

A

within tubular cells

22
Q

what should removal all nonvolatile acid

A

Net acid excretion

23
Q

what are the 3 forms in which nonvolatile acid is excreted

A

Free H
H2PO4
NH4

24
Q

what are the titratable acids in urin

A

H and H2PO4 to a pH of 7.4

25
Q

what is the pka of NH4

A

9 ( not titratable)

26
Q

what does the kidney use to regulate the acidity of urine

A

regulate HCO3 reabsorption

27
Q

how much HCO3 is replenished by the kidney in normal contions

A
  • kidney excretes acid equal to the nonvolatile load

- replenishes the HCO3 due to neutralizing the nonvolatile acids

28
Q

what are the options for renal regualtion of body pH that will produce urine with different pH

A
  • decrease body pH by not reabsorbing all HCO3
  • no effect on body pH by reabsorbing all HCO3
  • increase body pH by reabsorbing all and prodcuing more HCO3
29
Q

what does not reabsorbing all HCO3 do to the urine and body fluid

A

alkaline urine

acid body fluid

30
Q

what does reabsorbing all HCO3 do to the urine and the body fluid

A

urine and pH is neutral

31
Q

what does reabsorbing all and producing more HCO3 do to the urine and body fluid

A

acid urine

alkalinizes body fluid

32
Q

what is the most commone way the kidney regulates body pH

A

increase body pH by reabsorbing all and producing more HCO3

33
Q

why does the fact that HCO3 transport from tubular fluid into blood is not direct

A

HCO3 production and reabsorption results in H secretion

34
Q

where does Bicarb reabsorption begin

A

80% done in the Proximal tubule

35
Q

what in the tubular epithelial cells produces H and HCO3

A

CA cativity

36
Q

how is H secreted in tubular eptihelial cells

A

via Na/H antiporter

  • also H ATPase
  • H/K ATPase pumps
37
Q

what happens to the HCO3 that is is created via CA activity

A

transported/reabsorbed across basolateral membrane

38
Q

appart from the proximal tubule, where is HCO3 reabsorbed

A

Thick ascending limb of the loop of hendle (similar to proximal tubule)
late distal tubule

39
Q

how is HCO3 reabsorbed and H secreted in the LAte distal tubule

A

CA actvity produces H and HCO

- H secreted via H ATPase pumps and H/K ATPase pump

40
Q

what happens to secreted H to control pH

A

buffered by HCO3, HPO4, ammonia

41
Q

where is the last of all filtered HCO reabsorbed

A

Late distal tubule and collecting duct

42
Q

what cells reabsorb HCO3 in the late distal tubule and collecting duct

A

Intercalated cells

43
Q

how is HCO33 secreted and H reabsorbed

A

by a less common intercalated cell with reversed position of the H and HCO3 transporters

44
Q

should urine be acidic or alkaline

A

Alkaline (since body is alkaline)

45
Q

what does the kidney do to keep urine alkaline

A

Incomplete reabsorption of HCO3

- increase excretion of HCO3 by not neutralizing all the HCO3 that is in tubular fluid

46
Q

how does the body control the creation of HCO3 to keep urine alkaline

A

cells of proximal tubule detect intracellular pH and alter CA activity

47
Q

what does the body do if the body is acidic

A

Use phophate as an additional buffer to increase excretion of H

48
Q

why does the body produce NH4

A

after all the HCO3 is reabsorbed and HPO4 is depleted, NH4 acts as a 3rd buffer to increase the amount of H excreted

49
Q

is it alright if NH4 enters the body

A

No, its no good since it will be converted to urea and produce H as a result

50
Q

where is Nh4 produced

A

In the proximal tubules

51
Q

how is NH4 produces in the proximal tubules

A

metabolism of glutamine

52
Q

how is NH4 transported into tubular fluid

A

using Na, NH4 antiporters as HCO3 moves into the blood

53
Q

what regulates production of NH4 in the proximal tubule

A

systemic pH

- acidosis upregulates synth of enzymes for gluamine metabolism

54
Q

does responding to acidosis with NH4 production occure quickly

A

No, takes time

55
Q

how can more NH4 be added to the urine

A

diffusion trapping

56
Q

where is much of the nH4 leaving the proximal tubule reabsorbed

A

ascending limb of the loop of henle

57
Q

how does NH4 enter the interstial fluid in diffusion trappyin

A

NH4 substitutes K in the Na K 2Cl symporter in the medulla

58
Q

what is NH4 in equilibrium with in the medulla for diffusion trapping

A

Eq with NH3

59
Q

how does difusion trapping work

A

Once the charged NH4 is in the interstial fluid, it can’t go through the cells
-non polar NH3 can diffuse though into the lumen of nearly collecting ducks

60
Q

how does diffusion trapping increase pH

A

when NH3 diffuses into the collecting duct, it is protonated into NH4 and then again is trapped and cannot get reabsorbed

61
Q

what is respiratory acidosis

A

low pH due to CO2 build-up

62
Q

what causes respiratory acidosis

A

Impaired pulmonary function

63
Q

what is the renal compensatory response to respiratory acidosis

A

produce new HCO3

64
Q

what is respiratory alkalosis

A

high pH due to low PCo2

65
Q

causes of respiratory alkalosis

A

hyperventilation, anxiety, altitude, fever, drugs

66
Q

what is the renal compensaory response to respiratory alkalosis

A

excrete HCO3

67
Q

what is metabolic acidosis

A

Low pH due to low HCO3

68
Q

causes of metabolic acidosis

A

diabetic ketosis, diarrhea, renal failure

69
Q

what is the respiratory compensatory response to metabolic acidosis

A

Hyperventilate

70
Q

what is the renal compensatory response to metabolic acidosis

A

produce new HCO3

71
Q

what is metabolic alkalosis

A

high pH due to excess HCO3

72
Q

causes of metabolic alkalosis

A

vomiting
Antacids
Hemorrhages

73
Q

what is the respiratory compensatory response to metabolic alkalosis

A

hypoventilate

74
Q

what is the renal compensatory response to metabolic alkalosis

A

excrete HCO3

75
Q

where is the calcium found in the body

A

1% in the ICF
.1% of the ECF
99% in the bone

76
Q

what state is 1/2 the ECF calcium in

A

is free or complexed with anions

77
Q

why is it important the 1/2 of the ECF of calcium is free or complexed with anioins

A

can be filtered in the glomerulus

78
Q

what is the importance of calcium and phosphae

A

Cellular processes

79
Q

what organ systems regulate calcium

A

renal and digestive system to balance GI absorption and renal excretion

80
Q

what are some problems with hypocalcemia

A

increased excitability of neural and muscle tissue (tetany)

81
Q

what are some problems with hypercalcemia

A

cardiac arrhythmia and disorientation

- death

82
Q

how does pH affect free calcium levels

A
  • decrease plasma pH increases free calcium to filter and excrete
  • increase plasma pH leads to less free calcium
83
Q

what hormones regulate calcium

A

Parathyroid hormone (PTH)
Calcitriol (1,25 dihydroxyvitamin D)
Calcitonin

84
Q

what regulates all the hormones that regulate calcium

A

Calcium sensing recptor

85
Q

where is calcium sensing receptor found

A

plasma membrane of cells of the parathyroid gland, thyroid parafollicular cells, cells of the proximal tubule

86
Q

what stimulates release of parathyroid hromone

A

Hypocalcaemia

87
Q

what is the action of parathyroid hromone

A

bone resorption
increased renal Ca reabsorption
stimulate calcitriol production

88
Q

what does calcitriol come from

A

MEtabolism of Vitamin D

89
Q

what stimulates vit D metabolism to calcitriol

A

hypocalcaemia or hyophosphatemia (further stimulated from PTH)

90
Q

what is the action of calcitriol

A
  • stimulates active transport mechanism for Ca absorption in small intestine
  • faciliates action of PTH and increases renal Ca transport
91
Q

why is calcitonin release

A

respond to hypercalcaemia

92
Q

what odes calcitonin do

A

increase bone deposiion

93
Q

how is calcium reabsorbed in the nephron

A

paracellular transport/solvent drag

94
Q

who si calcium reabsorbed in the thick ascending limb

A

transcullar and paracellular (no solvent drag in in paracellular)

95
Q

where is calcium reabsoprtion regulates

A

transcellular regulated in distal tubule due to Ca transporters regulated by PTH

96
Q

how does the collecting duct reabsorb calcium

A

does not reabsorb the calcium