Kidneys, Water Balance and Electrolytes 1 Flashcards
Lecture
1
Q
major site of water reabsorption
A
proximal tubule
2
Q
how is water filtered and reabsorbed
A
through osmosis
3
Q
it reabsorbs ions more than water
A
loop of henle
4
Q
if ions are reabsorbed than water in the loop of henle what happens to the medulla and tubular fluid
A
medulla - concentrated
tubular fluid - diluted
5
Q
it controls the insertion of aquaporin water that are necessary for water reabsorption in the collecting duct
A
ADH
6
Q
ADH Synonym
A
Vasopressin, argipressin, or arginine vasopressin (AVP)
7
Q
makes ADH
A
Posterior pituitary
8
Q
looped blood vessels which maintain the concentrated nature of the medullary interstitium
A
Vasa recta
9
Q
most ideal substance for glomerular filtration rate
A
INULIN or LOTHALAMATE (lo)
10
Q
considered as the reference method and most accurate test for glomerular filtration rate
A
Clearance of Inulin
11
Q
measure of its solute/water ratio (amount of dissolved particles)
A
osmolality of body fluid
12
Q
best method to determine maximal concentration and dilution of urine
A
urine osmolality
13
Q
major extracellular cation
A
chloride
14
Q
measures the effective renal plasma flow (ERPF) in the absence of tubular functional impairment
A
Para aminohippurate clearance
15
Q
most common substance used to assess secretory function of renal tubules
A
PAH clearance
16
Q
reference method for ERPF
A
PAH clearance
17
Q
Normal range of PAH clearance
A
600-700 ml/min
18
Q
2 important properties of ECF
A
ECF volume and ECF osmolality
19
Q
directly dependent on the sodium content
A
ECF volume
20
Q
regulated by the levels of sodium and associated anion, glucose, urea, and proteins
A
ECF osmolality
21
Q
conditions that stimulates juxtaglomerular (IG) cells of the kidneys to release renin
A
hyponatremia, hypotension or potassium increase in blood (hyperkalemia)
22
Q
pure water loss or deficit
A
dehydration
23
Q
leads to increased ECF osmolality
A
dehydration
24
Q
Osmolality: blood diluted = __________
A
decrease osmolality
25
Osmolality: blood concentrated = ___________
increased osmolality
26
explain the mechanism of dehydration on plasma or ECF volume
in dehydration, it has less effect on the plasma or ECF volume since the body easily compensates for the fluid loss by recruiting water from ICF
27
pure water loss _________total body water but the __________ remains normal
pure water loss lowers total body water but the total body sodium remains normal
28
has greater effect on ECF or plasma volume
Water and sodium loss
29
it takes place especially in isotonic fluid loss
hypovolemia
30
what are the different types of water and sodium losses and its associated condition/happenings/symptoms
1. hypernatremic dehydration - water and food deprivation, excessive sweating, osmotic diuresis
2. normonatremic dehydration - vomiting, diarrhea
3. hypernatremic dehydration - diuretic therapy, salt-wasting renal disease, adrenocortical insufficiency
31
excessive intake of water and reabsorption of water
overhydration
32
major determinant of plasma osmolality
sodium
33
the only fluid compartment that is accesible for analysis
plasma
34
essential at the tissue-interstial fluid interface where they provide the colloid osmotic pressure (oncotic pressure)
Proteins
35
normal values of serum osmolality
285-319 mOsmol/kgH2O
36
seen in polydipsia
hypoosmolality
37
seen in excessive water loss
serum hyperosmolality
38
measures urine osmolality using osmometer or cryoscope
osmometry
39
refers to difference between the calculated osmolality using the equation (lowr) and the measured osmolality using any direct method (higher)
delta osmolality
40
this is used to evaluate acute ill or comatose patients
DELTA OSMOLALITY
41
delta osmolality: values considered a poor prognosis
>40 mOsmol/kgH2O
42
cause of increased delta osmolality
PEA:
Poison
Ethanol Overdose
Azotemia
43
caused by toxic alcohols, mannitol, and lorazepam infusions
osmolol gaps
44
it causes large osmolar gap but does not cause an anion gap metabolic acidosis
isopropyl alcohol
45
refer to the renal failure index and the fractional sodium excretion, respectively.
RFI and FeNa
46
used to differentiate between pre-renal and renal
cause of acute renal failure.
RFI and FeNa
47
RPL FeNa 1.0
pre-renal failure
48
RFI/FeNa >2.0
parenchymal renal failure e.g., acute tubular necrosis
49
evaluates the concentration and diluting ability of
kidneys
OSMOL CLEARANCE
50
what does osmol clearance measures
measure the amount of water cleared from the plasma resulting in urine that has the same osmolality as the plasma
51
for concentration and dilution ability of the kidneys and it is calculated as the difference between the total urine
volume and the osmol clearance.
FREE WATER CLEARANCE
52
positive free water clearance
urine is diluted compared to serum
53
negative free water clearance
urine is concentrated compared to serum
54
plasma osmolality is increased during?
Dehydration
Alcohol intoxication
Diabetes insipidus
Hypercalcemia
Administration of osmotically active drugs [e.g.,
mannitol]
55
plasma osmolality is decreased during?
Water intoxication (polydipsia)
Inappropriate retention of water in the kidney (SIADH and ectopic secretion of ADH)
In bronchogenic cancer lymphosarcoma
56
indirect measure of ADH content
OVERNIGHT WATER DEPARTMENT TEST
57
explain the steps involved in overnight water department test and what happens in patient with ADH deficiency and normal ADH response.
1.Water is withheld from the patient for 8 hours.
2. A series of timed blood and urine samples is then obtained as well as the weight of the patient.
3. Osmolalities of the samples are determined.
4. Patients with ADH deficiency: should show increasing serum osmolality and decreasing urine osmolality over the time tested.
5. Patients with normal ADH responses should not have weight losses greater than 3% and the decrease in water intake should stimulate the release of ADH.
58
functions of electrolytes:
Maintenance of osmotic pressure and hydration e.g., sodium
Buffering functions e.g., HCO,
Activators in enzyme reactions e.g., Mg
Normal neuromuscular excitability e.g., Ca
Redox reaction (electron transport) e.g., Fe
59
refers to the difference between the sums of the concentrations
of the principal cations (e.g., Na and K) and of the principal anions (e.g., Cl and HCO3-).
ANION GAP
60
can be used in the quality control of automated analyzers.
anion gap
61
An abnormal anion gap in healthy individuals
suggests an___________________.
instrument problem
62
NV:
AG= Na-(Cl + HCO3-)
7-14 mmol/L
63
NV:
AG = (Na + K)-(CI + HCO3-)
10-18 mmol/L
64
anion gap is increased in:
Ketoacidosis (starvation or diabetes)
Uremia
Methanol
Aspirin or ethylene glycol poisoning (lots of acid metabolites produced), severe dehydration
Lactic acidosis
65
anion gap is decreased in:
multiple myeloma
instrument error
protein error
66
most abundant cation in the extracellular fluid. It accounts for about 92% of the osmotically active solutes in the plasma.
SODIUM
67
main functions of sodium
water pull e.g., osmotic
activity of extracellular fluid
blood volume regulation,
neuromuscular excitability.
68
level of sodium is regulated by:
1. diet
2. kidney
3. RAA
4. Atrial natriuretic factor (ANF)
69
normal value of sodium in the ECF and ICF:
extracellular fluid is 135-145 mmol/L
intracellular fluid 4-10 mmol/L
70
seen in dehydration, azotemia, burns, diarrhea, vomiting, salt-losing nephropathies excessive use of diuretics, congestive heart failure, and SIADH(syndrome of inappropriate antidiuretic hormone hypersecretion).
Hyponatremia
71
seen in excessive sweating, diarrhea and renal loss and diabetes insipidus. May also be iatrogenic such as use of certain diuretics.
Hypernatremia
72
a colorimetric method test involves combining sodium with zinc uranyl acetate to produce sodium uranyl acetate precipitate.
Albanese-Lein
73
Addition of water to the sodium uranyl acetate precipitate produces ________________
produces a yellow solution.
74
major intracellular cation and 20 times greater in concentration inside the cells than outside.
POTASSIUM
75
Normal values of potassium in serum samples
3.8-5.0 mmol/L.
76
elevated levels of potassium
(>7.5 mmol/L) can
inhibit irritability of muscles, including the heart that may lead to paralysis or cessation of heartbeat
77
Low serum potassium (<3.0 mmol/L) may cause
increase muscle irritability and cause cessation of the heartbeat during systole.
78
primary organ responsible for controlling extracellular
potassium
kidney
79
minor regulator of potassium homeostasis.
gut
80
where potassium is secreted in
exchange of sodium under the influence of aldosterone.
colon and the rectum
81
hydrogen ions tend to be secreted in preference to the potassium resulting in hyperkalemia.
Acidosis
82
fewer hydrogen ions are available for excretion. As a result potassium secretion is favored. Hydrogen ions also move from the intracellular fluid
to the ECF while potassium moves from the ECF to
the ICF.
Alkalosis
83
during acidosis, what happens to potassium and hydrogen ions
Potassium moves into the extracellular fluid as
hydrogen ions are buffered into the cells.
84
during alkalosis, what happens to potassium and hydrogen ions
Hydrogen ions move from the intracellular fluid to the ECF while potassium moves from the ECF to the ICF.
85
normal serum concentrations of potassium
3.5 to 5.5 mmol/L.
86
major extracellular anion
chloride
87
decreased bicarbonate is
accompanied by a high chloride.
during metabolic acidosis
88
selectively admits all halogen ions but only bromide can possibly cause interference.
Chloride: ISE method
89
The membrane of the chloride ISE is a composite of ______ and _________
silver sulfide and silver chloride.
90
provides an accurate measure of the time of the current flow or, when properly calibrated, can give a direct read-out of the chloride concentration.
coulometric-amperometric method.
91
coulometric-amperometric method synonym
Cotlove titrator or chloridometer.
92
used in some semi-automated chloride analyzers
Zall color reaction
93
color that will occur as the next drop of mercuric nitrate is added as chloride ions are combined
colorless or faint pink
to violet.
94
the reagent in Zall color reaction contains __________ and _________
mercuric tioiocyanate and
ferric nitrate
95
Normal value of CSF chloride
115-132 mmol/L.
96
normal serum chloride concentration
98 to
108 mmol/L.
