renal 2 Flashcards
1
Q
what % of K+ is found wthin the ICF? ECF?
A
ICF= 98% of K+
ECF: 2% OF k+
2
Q
What is the function of the K+ concentration in the ECF?
A
extremely important for the function of excitable tissues (nerve and muscle)
3
Q
what is the resting potential of tissues directly related to?
A
intracellular and extracellular K concentrations
4
Q
what is hyperkalemia?
A
high concentration of K in the extracellular fluid (>5 mEq/L)
5
Q
what is hypokalemia?
A
low concentration of K in the extracellular fluid (<3.5 mEq/L)
6
Q
what maintains potassium balance?
A
kidneys
7
Q
from our dietary intake, how much K+ gets excreted and where?
A
90% through urine
10% through feces
8
Q
how is K+ filtered in the glomerulus?
A
freely filtered
9
Q
generally is there alot of K+ found in the urine?
A
generally not since most of it gets reabsorbed in the urine
10
Q
where can K+ be secreted at?
A
at the cortical collecting ducts.
11
Q
how does secretion of k+ differ from that of sodium and water?
A
because K+ secretion can occur at CCD unlike the 2 others
12
Q
what are the main factors that will regulate potassium secretion?S
A
- Dietary intake of potassium
2. Aldosterone
13
Q
how is K+regulated by aldosterone and daily intake
A
increase of K+ intake will increase plasma K thus increasing aldosterone secretion which increases aldosetine in plasma causing for an increased amount of k+ secreted in CCD thus increase in K excretion
14
Q
can the activation of Renin-aldosterone system cause the release of K+ for reasons other than high intake?
A
yes
15
Q
what is hyperaldosteronism?
A
The conditions in which the adrenal hormone aldosterone
released in excess.
16
Q
what is the most common cause for hyperaldosteronism?
A
denoma of the adrenal gland which
produces aldosterone autonomously.
17
Q
what does hyperaldosteronism lead to?
A
fluid volume, hypertension, hypokalemia.
suppressed. Metabolic alkalosis is often seen
18
Q
why is the H+ ion concentration tightly regulated in the ECF?
A
Metabolic reactions are highly sensitive to the hydrogen ion concentration of the environment.
19
Q
what is the regulated concentration of H+? pH?
A
pH ~ 7.4
[H+] ~ ~40 nmol/L
20
Q
what is equivalent to losing a bicarbonate ion in the body?
A
its the equivalent to gaining a h+ ion
21
Q
what is equivalent to gaining a bicarbonate ion in the body?
A
its the equivalent to losing a h+ ion
22
Q
what are changes in K+ excretion maily due to?
A
changes in K+ secretion of the CCD
23
Q
what is k+ secretion in the CCD coupled with?
A
coupled with Na reabsorption
24
Q
what may the production of non volatile acids due to metabolic reactions cause?
A
gain in h+ ions
25
what are some non volatile acids?
Phosphoric acid
Sulfuric acid
Lactic acid
26
how much non volatile acids are produced in the average person daily?
40-80 mmol of H+ per day
27
what is a buffer?
Any substance that can reversibly bind hydrogen ions
28
how is pH measured?
-log [H+]
29
what happens if no buffers are present?
H+ concentrations would greatly vary
30
what are some of the major EC buffers?
CO2/HCO3- system
31
what are the major IC buffers?
phosphates and proteins
32
do buffers allow to eliminate H+ ions?
no, it will only “lock them up"
33
what controls the ultimate balance of H+ ions?
Respiratory system
| kidneys
34
how will the respiratory system control H+ balance?
by controlling CO2
35
how will the kidneys control the h+ balance?
by controling bicarbonate levels
36
how do the kidneys function under low [H+]?
Kidneys excrete HCO3- thus equivalent to a gain of H+
37
how do the kidneys function under high [H+]?
kidneys will produce new bicarbonate ions and add it to the plasma
38
what state are we in under low [H+]
high pH thus alkalosis
39
what state are we in under high [H+]
low pH thus acidosis
40
what is Ka (dissociation) for CO2/HCO3-
0.03 is solubility of CO2 at 37 degrees celsius
41
what is pH equivalent to?
pH = -logKa + log ( [HCO3-] / 0.03[CO2] )
42
what is bicarbonate excretion equivalent to?
HCO3- FILTERED - HCO3- SECRETED -HCO3- REABSORBED
43
Normally what happens to HCO3-? except?
generally the kidneys reabsorb all filtered HCO3-, except in cases of alkalosis
44
what mediated the transport of H+ from tubular epithelial cell to tubular lumen
H+/K+-ATPase Na+/H+ antiporter
45
what happens to Hco3- once it dissociated in the proximal tubule
it gets sent into the ISF
46
what happens to the end product H+ from H2C03 in the proximal tubule?
H+ is secreted in tubule lumen
47
what happens in the tubule lumen when H+ meets HCO3- which has been filtered?
forms h2o and co2
48
what % of HCO3- rebasorption occur in the proximal tubule? Tubule apical lumen? CCD?
```
PT = 80%,
TAL = 15%,
CCD = 5%
```
49
how is the addition of new HCO3- in the plasma achived?
1. by H+ secretion and excretion on nonbicarbonate buffers
| 2. by glutamine metabolism with NH4+ excretion.
50
both processes of addition of HC03- can be viewed as what?
h+ excretion process by the kidneys
51
do the kidneys contribute enough HCO3- to compensate for the h+ ions from non volatile acids?
yes
52
when does the addition of HCO3- occur?
only after all HCO3- has been reabsorbed and no longer availible in the lumen
53
where does the addiiton of HCO3- occur mainly through glutamine metabolism?
in the proximal tubule
54
addition of HCO3- to the plasma is also know as?
H+ excretion bound to NH3
55
where does glutamine come from?
ISF AND then from the lumen after being filtered
56
what is glutamine broken down into?
HCO3- and NH4+
57
what happens to HCO3- and NH4+
both get secreted into the lumen
58
in the H+ secretion on nonbicarbonate buffers, where does H+ secreted in the lumen bind to?
binds to phophate, hpo4-2
59
what does respiratory alkalosis result from?
altered respiration causing for low [H+]
60
what does metabolic alkalosis result from?
Other causes leading to low [H+]
61
what does respiratory acidosis result from?
altered respiration causing for high [H+]
62
what does metabolic acidosis result from?
Other causes leading to high [H+]
63
what happens in the case of respiratory acidosis
increase in CO2
64
what happens in the case of metabolic acidosis?
decrease of HCO3-
65
what happens in the case of metabolic alkalosis?
increase of HCO3-
66
what happens in the case of respiratory alkalosis?
decrease in in CO2
67
what is the primary abnormality associated with respiratory disorders?
changes in CO2 levels
68
what is the primary abnormality associated with metabolic disorders?
changes in HCO3- levels
69
how does the body respond to acidosis?
1. Sufficient H+ are secreted to reabsorb all the filtered HCO3-.
2. Still more H+ are secreted and this contributes new HCO3- to the plasma as these H+ are excreted bound to non-HCO3- buffer such as HPO42-.
3. Tubular glutamine metabolism and ammonium excretion are enhanced, which also contributes new HCO3- to the plasma.
70
what is the net effect of the body in response to acidosis?
More new HCO3- than usual are added to the plasma, thereby compensating for the acidosis
71
how is the urine in cases of acidosis?
acidic
| lowest pH ~ 4.4
72
how does the body respond to alkalosis
1. Rate of H+ secretion is inadequate to reabsorb all the filtered HCO3-, so the significant amounts of HCO3- are excreted in the urine.
2. There is little or no H+ secretion on non-HCO3- urinary buffers.
3. Tubular glutamine metabolism and ammonium excretion are decreased, so that little or no new HCO3- is contributed to the plasma from this source.
73
what si the net result of the body’s response to alkalosis?
Plasma HCO3- will decrease, thereby compensating for the alkalosis.
74
how is the urine during alkalosis?
highly alkaline
| pH > 7.4
75
how do kidneys compensate to increase CO2 concentration in respiratory acidosis?
increasing hco3-
76
how do kidneys compensate to decrease CO2 concentration in respiratory alkalosis?
decrease hco3-
77
how does the respiratory system compensate to metabolic acidosis?
increase H+, decrease HCO3 and thus decrease of PCO2
78
how does the respiratory system compensate to metabolic alkalosis?
increase HCO3, decrease H , thus increases PCO2
79
Give a clinical example of when respiratory acidosis may occur?
respiratory failure with CO2 retention, severe asthma
80
Give a clinical example of when respiratory alkalosis may occur?
hyperventilation (e.g. high altitude)
81
Give a clinical example of when metabolic alkalosis may occur?
vomiting (loss of H+ in vomits), hyperaldosteronism (increased H+ secretion in DCT and CCD)
82
Give a clinical example of when metabolic acidosis may occur?
diarrhea (loss of HCO3- in diarrhea), renal failure (accumulation of inorganic acids)
83
what are the drugs used to uncrease the volume of urine excreted?
diuretics
84
what do diuretic act on?
tubules
85
what is inhibited by diuretics?
inhibit reabsorption of Sodium along with Cl, and/or bicarbonate
86
what does the inhibition of ions by diuretics cause?
increased excretion of these ions hence increased water excretion
87
what do loop diuretics act on?
the thick ascending limb of the loop of Henle.
88
what is inhibited by loop diuretics?
Inhibits cotransport of sodium, chloride and potassium
89
what type of diuretic is furosemide?
loop diuretic
90
what happens to Na reabsorption when consuming loop diuretic?
Diuretics will block reabsorption in the TAL
91
what % of Na reabsorption occurs in TAL?
25%
92
what is inhibited by potassium spanning diuretics?
Inhibit sodium reabsorption in the CCD, and also inhibits potassium secretion there
93
what happens to the K+ plasma concentration when using potassium spanning diuretics?
it will not decrease as it would with other diuretics
94
what gets blocked by potassium spanning diuretics?
block the action of aldosterone or block the (aldosterone-regulated) epithelial sodium channel in the CCD.
95
give a few examples of potassium spanning diuretics and their function?
amiloride (block sodium channel)
| spironolactone (block aldosterone receptor)
96
what happens when alsosterone is blocked?
blocks the secretion of K and Na uptake since aldosteron acts on Na/K atpase, K channel and Na channel
97
why can diuretics be used in clinical settings?
in cases of renal retention of salt and water leading to edema
98
what happens in cases of congestive heart failure?
heart failure lowers CO, which is percieved by baroreceptors as a lack of fluid/Na and sends info to the brain causing kidneys to reabsorb Na and H20 which will accumulate in the lungs
99
what happens in cases of hypertension?
renal retention of salt and water may be contributing to high blood pressure
100
what are some common features associated with kidney diseases and renal failure?
-proteinuria
-accumulation of waste in blood
high [potassium] --> hyperkalemia
metabolic acidosis
anemia
decreased secretion of vit D3 leading to hypocalcemia
101
what are some of the waste products which may accumulate in blood in cases of renal failure or kidney diseases?
urea, creatinine, phosphate, sulfate
102
why is anemia possible in cases of kidney failure?
due to decreased secretion of EPO
103
what is involved in renal remplacement therapy?
1. Hemodialysis
2. Peritoneal dialysis
3. Kidney transplantation
104
when is a patient subject to renal remplacement therapy?
when more than 90 % of nephrons stop working
105
what is hemodialysis?
its a blood cleaning treatment
106
how does hemodialysis work>
Arterial blood is run through pump, anticoagulant is added, goes through fibers from top to bottom. Dialysis fluid is run bottom to top across a membrane, and molecules are exchanged. Blood is then returned to patient through vein.
107
what is used as a dialysis memebrane?
abdominal peritoneum
108
where is dialisis fluid injected?
into the cavity via a tube inserted through the abdominal wall.
109
where do solute from a patient diffuse?
the solutes from patient blood will diffuse into dialysis fluid
110
can dialysis be done at home
yes, requires to be done a few times per day
111
can kidney transplantation be done from both living and decreased donor?
yes if compatible.
| must be recently deceased
112
what type of treatment must be applied immediately after kidney transplant?
anti-rejection treatment
113
can donor functions well with a single kidney?
yes
114
are we short on organs?
yes, shortage is an issue
