Renal 1 Flashcards
1
Q
The nephron does the work of making urine to remove waste and reabsorbing electrolytes to maintain the what?
A
ECF
2
Q
Loss of how many nephrons pushes you towards kidney failure/uremia?
A
> 50%
3
Q
Age of 40 does what with nephrons?
A
Decrease about 10%/decade
4
Q
Age of 80 does what with nephrons?
A
-40%; 480K-720K
5
Q
What are the 3 early nephron units?
A
Glomerulus
Proximal tubule
Descending Loop of Henle
6
Q
Net function of glomerulus?
A
Filters and hold capillary beds
7
Q
Net function of proximal tubule?
A
Reabsorbs salts and drug secretion
8
Q
New functions of descending LOH?
A
Reabsorbs water
9
Q
What are the mid to late parts of the nephron?
A
Ascending loop of henle
Distal convoluted tubule
Collecting duct
10
Q
Net functions of ascending LOH?
A
NaCl reabsorption
11
Q
Net functions of distal convoluted tubule?
A
Adjusts salts
12
Q
Net functions of collecting duct?
A
Adjusting water
13
Q
What size of kidneys is only how much of the body mass?
A
.5%
14
Q
Kidney gets how much of the cardiac output?
A
20%
15
Q
Calculation of RBF:
A
5L/min x 20% = 1L/min
16
Q
Name the 9 steps of blood flow through kidney:
A
- Arcuate artery
- Interlobular artery
- Afferent arteriole
- Glomerulus
- Efferent arteriole
- Peritubular capillaries
- Vasa recta
- Interlobular vein
- Arcuate vein
17
Q
Why does such a small organ get such a large amount of blood flow?
A
For the process of filtration because ischemia causes problems in nephron
18
Q
Where is there high pressure in the nephron and what is the function of that?
A
In the afferent arterial to the glomerulus
For filtration
19
Q
What does the high pressure look like with hydrostatic and oncotic pressure?
A
Hydrostatic > oncotic
20
Q
Where is there low pressure in the nephron and what is the function of that?
A
Efferent arterial and peritubular capillaries
Reabsorption of fluid
21
Q
What does the low pressure look like with hydrostatic and oncotic pressure?
A
Oncotic > hydrostatic
22
Q
What does the vasa recta provide pressure wise?
A
Low pressure osmotic counter current
23
Q
Filtered load equation?
A
Plasma [x] x GFR
24
Q
What does the filtered load equation tell you?
A
How much is actually filtered
25
What are the 3 layer barrier in the glomerulus that helps promote filtration and limit what is able to cross into the nephron?
1. Fenestrated capillary endothelium
2. Glomerular basement membrane
3. Podocytes with filtration slits
26
What 3 things determine what crosses the membrane?
1. Glomerular filtration membrane
2. Size and charge of filtered molecules
3. Net filtration pressure
27
What charge is the glomerular basement membrane?
Negative
28
When sizes are equal, what charge has a harder time being filtered?
Negative charged substances
29
When sizes are equal, which charge substances are easily filtered?
Positively charged substances
30
From easiest to hardest what is filterable: inulin, glucose, albumin, water, sodium, myoglobin, urea, hemoglobin
Urea, glucose, sodium, water, inulin
Myoglobin
Hemoglobin
Albumin
31
What is the major driving force of filtration?
High PGC (glomerular capillary hydrostatic pressure)
32
Net filtration pressure (NFP) equation?
(P GC-P BS)-(pie GC-pie BS)
33
Normal value for glomerular capillary hydrostatic pressure?
50
34
Normal value for Bowman’s space oncotic pressure?
0
35
Normal value for Bowman’s space hydrostatic pressure?
10
36
Normal value for glomerular capillary oncotic pressure?
25
37
Why is there no Bowman’s capsule colloid osmotic pressure?
Shouldn’t filter proteins because they don’t make it into the capsule
38
If you increase P GC then what happens to the filtration?
Increase
39
What 2 factors do GFR come down to?
1. Permeability glomerular capillary
| 2. Net filtration pressure
40
Rate at which filtrate is formed by both kidneys per minute
Glomerular filtration rate (GFR)
41
What is the key measure of renal health?
GFR
42
GFR is passive process that is driven largely by what?
NFP (particularly high P GC)
43
What is the only thing that glomerular can not filtrate from plasma?
Proteins
44
Is it practical to measure GFR by Kf or NFP?
No
45
What represents how much of a substance can be removed from a certain amount of plasma volume in a given amount of time?
Clearance
46
We can use clearance to estimate what?
GFR
47
Clearance equation:
Urinary excretion ([U]x[UV])/plasma [P]
48
What is the gold standard to find renal clearance?
Inulin
49
What are the 4 reasons why inulin is ideal for renal clearance?
1. Non-toxic and infusible
2. Freely filterable by the kidney
3. Not reabsorbs, secreted, metabolized, synthesized or stored in any way
4. Unable to alter GFR
50
Clearance of inulin is equal to what?
GFR
51
What are the 4 steps to use inulin in renal clearance?
1. Infuse a substance into the pt
2. Achieve steady plasma conc
3. Collect urine and blood
4. Calculate clearance
52
What is the second best way to calculate renal clearance?
Creatinine
53
What are the 5 reasons why creatinine is used for renal clearance?
1. It’s a metabolite produced by creatinine phosphate metabolism (no infusion needed)
2. In normal healthy person the rate of production is constant (rate of production=rate of excretion)
3. Freely filterable by the kidney
4. Not reabsorbed
5. Small secretion into the nephron (~10%)
54
What are the 3 steps to used creatinine for renal clearance?
1. Collect blood
2. Measure creatinine
3. Use prediction equation
55
How is plasma Cr related to GFR?
Inversely
56
Doubling plasma Cr represent what with GFR?
Large reductions
57
A 50% reduction in GFR from 125 to 62.5 induces what to plasma Cr?
100% increase from 1 to 2
58
Does GFR decline naturally with aging?
Yes
59
Stage 1 CKD; kidney damage with normal GFR
>90 GFR
60
Stage 2 CKD; kidney damage with mild GFR
89-60 GFR
61
Stage 3A CKD; mild to moderate GFR
59-45 GFR
62
Stage 3B CKD; moderate GFR
45-30 GFR
63
Stage 4 CKD; severe GFR
30-15 GFR
64
Stage 5 CKD; kidney failure
<15 or dialysis GFR
65
What is the normal value of GFR?
125
66
GFR of both kidney in ml/min and L/day?
125 ml/min
| 180 L/day
67
What is the normal plasma volume (PV)
3L = filtered 60 x’s/day
68
About how much of volume filtered (GFR) is reabsorbed?
~99%
69
What is the calculation for RBF:
5-6L x 20% = 1000-1200ml/min
70
How much RBF goes through the kidney when comparing body weight?
3.5 ml/min/g (
71
What is the % plasma filtered into the renal tubules?
Filtration fraction (FF)
72
What is the FF equation?
GFR/ renal plasma flow (RPF)
73
What is the FF:
125/600 = 20%
74
What is the normal renal plasma flow?
600 ml/min
75
Is O2 a critical factor for regulating RBF?
Now
76
Is high RBF for filtration or metabolism?
Filtration, not metabolism
77
If we constrict only the AA what would happen to RBF, PGC, GFR?
Everything decreases
78
If we constrict only EA, what would happened to RBF, PGC, and GFR?
Decrease RBF
Increase PGC
Maintain GFR
79
What does the kidney use to protect RBF and GFR from changes in MAP?
Neuroendocrine regulation and intrinsic autoregulation
80
What is the normal MAP for kidney?
80-180mmHg
81
What is neuroendocrine regulation?
Vasoconstrictors vs dilators
| Can be impaired during disease (HTN)
82
Neuroendocrine influences what?
RBF
83
NE/Epi primary effect and where?
Constrictor on AA
84
What does NE/Epi do to the RBF?
Decrease
85
Pain, stress, exercise, hemorrhage deals with what agent?
NE/Epi
86
Primary affect of AngII and ADH/AVP and where?
Constrictor on EA
87
What does AngII and ADH/AVP do to RBF?
Decrease
88
Countered in AA via NO and PG is affected with what agent?
AngII and ADH/AVP
89
Adenosine (ATP) has what primary effect and where?
Constrictor on AA
90
What does adenosine (ATP) cause in RBF?
Decrease
91
Released of macula densa during increase tubular flow deals with what agent?
Adenosine (ATP)
92
NO primary effect and where?
Dilation on AA and EA
93
What does NO do to RBF?
Increase
94
Sheer stress; helps keep GFR constant despite constrictors deals with what agent?
NO
95
Renal prostaglandins primary effect and where?
Dilation on AA
96
What does renal prostaglandins do to RBF?
Increase
97
Helps keep GFR constant depsite constrictors deals with what agent?
Renal prostaglandins
98
ANP primary affect and where?
Dilation on AA
| Constriction on EA
99
High atrial pressure deals with what agent?
Dilation of ANP
100
Dopamine primary effect and where?
Dilation on AA and EA
101
Dopamine causes what with RBF?
Increase
102
Stretching the vascular wall of blood vessel will have a reflexive contraction explains what?
Myotonic mechanism
103
The reflexive contraction in myogenic mechanism is a what property?
Intrinsic property of smooth muscle
104
Each nephrons distal tubules (downstream), can communicate with the arterials of the glomerulus (upstream) to alter GFR explains what?
Tubuloglomerular feedback (TGF)
105
When Na in distal tubules is high, what happens with the GFR?
Lower
106
When Na in distal tubules is low, what happens to GFR?
Rises
107
Tubuloglomerular feedback helps keep what in nephron constant, which helps maintain ECFV?
GFR and Na
108
Renal triad of AKI is:
Decrease in GFR
Decrease in urine output
Increase in BUN
109
What is the first step of urine production?
Filtration
110
Sevoflurance represents a theoretical risk for what?
AKI
