L7 Renal Flashcards
(110 cards)
1
Q
Acute kidney injury
A
sudden, temporary, but sometimes fatal loss of kidney function
2
Q
Chronic Kidney Disease
A
any condition that decreases kidney function over a period of time
3
Q
End-stage renal disease
A
total and permanent kidney failure
4
Q
Two common risk factors for Chronic Renal Failure
A
Diabetes
Hypertension
5
Q
Drugs to avoid with kidney disease
A
antibiotics
antidepressants
antivirals
chinese herbal medicines
cholesterol lowering statins
diuretics
NSAID pain relievers
Stomach-acid reducers
6
Q
Consequences of renal failure
A
HTN
Metabolic Acidosis
Muscle Weakness
Osteoporosis
Anemia
CNS/PNS?autonomic dysfunction
7
Q
Renal Failure and Osteopororsis
A
excreting calcium more, retaining phosphate
8
Q
Renal Failure and ANemia
A
kidneys produce erthryopoetin, decreases with failure
9
Q
Renal Failure and CNS, PNS, Autonomic Dysfunction
A
buildup of urea, increased BUN. Toxic to nerves
10
Q
Plasma K+ level
A
3.7 to 5.1 mEq/L
both hypo and hyper are dangerous, especially for cardiac function
you should always review electrolyte panel
11
Q
BP Control
A
Lifestyle modifications
Anti-hypertensive medications
12
Q
Lifestyle Modifications (BP control)
A
DASH diet
exercise
no smoking
limited alcohol
13
Q
Anti-hypertensive medications (BP control
A
ACE inhibitors
BBs
CCBs
Diuretics
vasodilators
14
Q
Management of renal disease
A
BP control
Anemia Control
Dialysis
Renal transplantation
15
Q
Hemodialysis
A
Cleaning the blood, specifically from nitrogenous waste (urea and creatanine) products, metabolites from drugs
prescribed at less than 15% of function left
16
Q
Arteriovenous fistula for hemodialysis
A
Surgically created connection between an artery and a vein that makes needle placements for dialysis easier
Takes 6 weeks to heal
Can be used for years, allows blood to flow out/in w/out damaging veins
17
Q
Precautions for arm with AV fistula
A
No BP
Keep the port clean
No heavy lifting
Do not sleep with arm under head
18
Q
Peritoneal Dialysis
A
allows individuals to do their own dialysis
blood is cleaned w/out removing it from the body
19
Q
Can exercise training help patients with CKD?
A
Adults w/CKD have VO2max that are 1/3 to 1/2 that of age-matched sedentary adults w/out kidney disease
Exercise can: improve BP control, increase functional capacity, increase H/H levels, improves glucose metabolism
20
Q
Functions of the kidneys
A
- Regulate ECF volume through urine formation
- Regulate blood volume and BP
- Regulate concentration of electrolytes
- Regulate concentration of waste products in blood
- Regulate pH
- Secrete erythropoietin, production of RBCs
- Excrete metabolites
21
Q
Kidney Medulla
A
-renal pyramids separated by renal columns
-pyramid contain minor calyces, which become major calyces, and then renal pelvis
22
Q
Nephron
A
urinary tubules and associated blood vessels
23
Q
Filtration
A
Blood to tubules
water and solutes that pass from the plasma to inside of glomerular capsule and tubules
24
Q
Secretion
A
Blood to Tubules (active)
active transport of substances from plasma into tubules
opposite of reabsorption
25
Reabsorption
Tubules to blood
return of filtered water and molecules from tubules into plasma
26
Excretion
Fluid and solutes leave body in urine
27
Proximal Convoluted Tubule (Reabsorb)
65% of H2O, NaCL, K+ Reabsorbed
100% of AA and glucose reabsorbed
28
Loop of henle makeup
Thin descending limb
Thin ascending limb
Thick ascending limb
29
Loop of henle (reabsorb)
20% H2O, NaCL reabsorbed
30
Macula Densa
sense the glomerular filtration rate (GFR)
cells are in the ascending loop
31
Juxtaglomerular apparatus
macula densa and afferent arterioles
32
Hormones of collecting ducts
aldosterone
ADH/vasopressin
33
Descending Limb
Passive H2O reabsorption
water goes into the vasa recta
34
Ascending Limb
NaCL active reabsorption, goes into the interstitum
35
Reabsorption of H2O and NaCL
85% of it is not under hormonal control
36
Pathway after a nephron
Collecting duct > minor calyx > major calyx > renal pelvis > ureter > bladder > urethra
37
Cortical nephrons
urine formed here is about the same concentration as plasma
short loops of henle
38
Juxtamedullary nephrons
Critical to produce concentrated urine
long loops of henle
39
Osmosis
passive diffusion of water from hypotonic to hypertonic solution
40
Renal blood vessels
Afferent arteriole
Glomerulus
Efferent arteriole
Vasa Recta
41
Afferent arteriole
delivers blood into glomeruli
42
Glomerulus
capillary network produces filtrate that enters urinary tubules at glomerular capsule
43
Efferent arteriole
delivers blood from glomeruli to peritubular capillaries
44
Vasa recta
-straight arterioles and venules that lie parallel to the loop of henle
-blood flows through the tight turn at very slow rate
-Proximity of vasa recta to loop of henle AND the slow flow rate are critical to maintain the concentration gradient in renal medulla
45
Bowman's capsule
surrounds glomerulus
where GLOMERULAR FILTRATION occurs
46
What does RBC in the urine indicate?
that there has been damage to the glomerular filtration membrane
47
What makes up the glomerular filtration membrane?
(PLASMA) Capillary endothelium
Basement membrane
Foot processes of podocyte of glomerular capsule
48
Endothelial cells of glomerular capillaries
have LARGE pores
permeable to plasma, H2O, solutes
pores do not allow formed elements of blood to pass through
49
Basement Membrane
Filtrate must pass through basement membrane
thin glycoprotein layer that is negatively charged, does not allow plasma proteins to pass through
50
Podocytes of visceral layer of Bowman's capsule
spaces between foot pedicels from small filtration slits that allow filtered molecules to enter interior Bowmna's capsule
51
Ultrafiltrate
fluid that enters the glomerular capsule
formed under the hydrostatic pressure of blood
52
Glomerular filtration rate
measures kidney function
volume of filtrate removed from the blood each minute
averages 180 L/day
decreases with age and w/kidney dysfunction and disease
53
How to estimate GFR
can be closely estimated by blood, creatinine
one of the best tests to measure kidney function
used to determine stage of kidney disease
54
Why does GFT need to be regulated?
needs to be high enough to eliminate wastes
shouldn't be so high that it causes excessive BV loss
55
How is GFR regulated?
vasoconstriction or vasodilation of afferent arterioles affects the rate of blood flow to the glomerulus
56
Forces across glomerular capillaries
1. Beginning net = +16 mmHg
2. End net = 0 mmHg
Pressure going into bowman's space stays the same, and the pressure going out from bowman's space. But, the pressure of the glomerular capillary changes due to the amount of plasma proteins
57
What systems regulate GFR?
sympathetic nervous system
autoregulation of intrinsic to the kidneys
renin-angiotensin system
58
SNS activation of glomerulus
causes vasoconstriction of afferent arterioles
causes decreased glomerular capillary hydrostatic pressure AND decreased urine output
ultimately preserves blood volume to muscles and heart
59
Renal autoregulation
ability of kidneys to maintain a relatively constant GFR under widely changing BPs
allows GFR to remain constant, even with changing BP
60
How does autoregulation occur?
Different from SNS input
1. Effects of locally produced chemicals on afferent arterioles
2. Tubuloglomerular feedback from macula densa
61
What is reabsorbed and filtered?
glucose and AA, water
62
What is never filtered?
potassium
antibiotics
formed elements/plasma protein
63
Reabsorption details
180 L of ultrafiltrate are produced/day
only 1-2 L urine is excreted
most filtered solutes and H2O from the ultrafiltrate are returned back into the peritubular capillaries
64
Obligatory water loss
minimum of 400 ml/day urine is necessary to excrete metabolic wastes (urea and creatane)
this is what you need to survive
65
Nephron makeup
urinary tubule and associated blood vessels
66
Reabsorption in PCT
1. 65% of salt and water that enter the glomerular capsule is reabsorbed across PCT and returned to the plasma
2. Total solute concentration is same as plasma (isosmotic)
67
How is that fluid in PCT is 1/3 of original volume but it is still isosmotic with plasma?
Active Na+ transport and osmosis
68
What things are reabsorbed?
Na+
Cl-
H2O follows by osmosis
glucose
amino acids
65% of Na, Cl, H2O, and K+ is reabsorbed
100% of glucose and AA are reabsorbed
69
Proximal convoluted tubule
single layer of cuboidal cells
Na/K ATP located in sides of cell membrane creates GRADIENT of Na, causes diffusion into cell
Cl follows electrical gradient
H2O follows by osmosis
70
Glucose Reabsorption
100% occurs in PCT
filtered but not excreted (along with AAs)
Cotransporters help to reabsorb glucose and AA
71
What occurs in cotransporter saturation?
amount of cotransporters are limited
Glycosuria = glucose in urine
happens when glucose is >180 mg'dl
sign of diabetes
72
Osmolality and Tubules
the interstitial fluid surround teh tubules has to be hypertonic to pull water out of the tubules
73
How is the concentration gradient maintained in the kidneys?
countercurrent multiplier system
vasa recta
74
Countercurrent multiplier system
amount of salt determines how much H20 and Na leaves
refers to the interaction between the descending and ascending loop of henle
1. More salt is added by PCT
2. Higher osmolarity of ECF, the more water that leaves the descending limb
3. The more water that leaves, the saltier the fluid in the tubule becomes (more urine is produced)
4. The saltier the fluid in the ascending limb, the more salt the tubule pumps out
positive feedback loop
75
Role of Vasa Recta
pulls the water leaving the tubules into the blood to prevent dilution of the interstitial fluid
also allows NA to remain in the intersitial fluid of the medulla
76
Role of urea
nitrogenous waste product from protein
both ascending and terminal collecting duct are permeable to urea
recycyled through these two areas, contributing to the osmolality of the intersitial fluid in the inner medulla
77
Order of the nephron
Bowman's capsule
PCT
Loop of henle
Macula densa
DCT
Collecting Duct
78
Order of chemical processes in nephron
Filtration
Reabsorption
Secretion
Excretion
79
Collecting ducts anatomy
receive fluid from DCTs of nephrons
pass through renal pyramid into minor calyx
80
Functions of collecting ducts
1. Reabsorption--> h2o, influenced by ADH
2. Secretion--> potassium, influenced by aldosterone
81
Dehydration and ADH
Dehydration causes ADH to be released
1. Increased salt/increased plasma osmolality
2. Triggers osmoreceptors/thirst
3. release of ADH from posterior pituitary
82
Vasopression receptors
V1: vascular smooth muscle --> vasoconstriction
V2: cells of renal collecting duct --> water reabsorption
83
Diabetes Insipidus
deficiency of ADH/vasopression
84
Aldosterone
The final concentrations of Na and K are varied in DCT and collecting ducts because of aldosterone
Triggers: angiotensin 2, high plasma K, low plasma Na
increases blood pressure, reabsorbs Na and K secretion. results in water retention in exchange for loss of K
85
How do the kidneys sense your BP?
juxtaglomerular apparatus
--> granular cells and macula densa
86
H2O and Collecting Ducts
H2o is drawn out by osmosis
the rate is determined by the # of aquaporins
permeability to H2o depends on the presence of ADH
ADH helps to bind to CD cells, incorporating more aquaporins into cell membrane, allowing water reabsorption
87
How does aldosterone reabsorb Na and secrete K?
Aldosterone inserts luminal Na channels, promotes synthesis of Na, K, ATPase in the principal cells of the CDs
88
Role of aldosterone in K secretion
Final blood K is controlled by aldosterone
--> this only impacts FINAL, not the 90% that is reabsorbed early on in the nephrons
Aldosterone is the ONLY thing that controls K being excreted
89
Hyperkalemia
could be caused by hypoaldosteronism, renal failure, diurectics, chronic acidosis
you would have low BP, severe cardaic arrthymias, renal failure
90
Hypokalemia
could be caused by hyperaldosteronism, low potassium diet, diuretics, chronic allkalosis
also would experience hypertension, muscle spasms
91
Acid-base regulation
Kidneys secrete H+ and reabsorb HCO3
H secretion occurs in proximal tubule in exchange for absorption of Na
Kidneys reabsorb almost all filtered HCO2 and excrete H, so urine is slightly acidic
H is excreted as HPO4 or as ammonia
92
Relationship of Na, K, and H
Na is reabsorbed from CD, which creates an electrical K to be secreted (Na out, K in)
Plasma K levels indirectly affects plasma H
In severe acidosis, H is secreted at expense of K, which can cause hyperkalemia
93
Diuretics
drugs that increase urine volume
increases frequency and volume
prescribed for HTN, heart failure, edema
inhibit the reabsorption of salt
classes of strong, weak, potassium sparing
94
Strongest diuretics
loop and thiazide diuretics
inhibit salt and H2o reabsorption by as much as 25% (lasik)
95
Potassium Sparing Diuretics
Prevent excessive K+ excretion that tends to occur with above diuretic classes
(spironolactone)
96
Hypokalemia and Diuretics
--> these diuretics increase Na delivery to DCT, causing increased K loss. Na is reabsorbed, K and H are secreted
97
If a substance is neither reabsorbed nor secreted...
the amount excreted = amount filtered
would be a perfect measure of GFR
no endogenous substance in the body perfectly fits this criterion
98
GFR and inulin
inulin = fructose polymer that is neither reabsorbed or secreted
The GFR of inulin equals the clearnce of inulin
GFR = (inulin concentration x rate of urine formation)/plasma concentration
99
Clearance
volume of plasma from which a substance is completely removed in 1 minute by excretion into urine
we can measure GFR by the clearance of a substance
100
How can.GFR be measured?
Inulin levels (scientific)
Creatinine levels (clinical)
101
Creatinine and GFR
filtered and secreted
excretion closely matches GFR, slightly overestimates it
if GFR decreases, plasma creatinine rises--> if kidneys are failing, then the creatinine levels rise
no normal value
102
Blood urea nitrogen (BUn)
normal = 7-20
higher = kidney disease, heart failure, excessive protein levels
lower than normal = liver failure, low protein, malnutrition
103
A low eGFR...
high creatinine
high BUN
high albumin in urine
104
If substance is not filtered
the renal clearance rate = zero
proteins
105
If substance is filtered, but not reabsorbed or secreted
renal clearance rate = GFR
inulin
106
If substance is filtered and partially reabsorbed
renal clearnace rate is less than GFR
urea
107
If substance is filtered and completely reabsorbed
the renal clearance rate is zero
glucose
108
If substance is filtered and secreted
renal clearance rate is greater than GFR
109
If substance is filtered, reabsorbed, and secreted
the renal clearance rate is variable
potassium
110
GFR vs Renal Clearance Rate
GFR specifically focuses on the filtration of plasma through the glomeruli
renal clearance rate encompasses the complete removal of a substance from the blood, considering both filtration and any additional processes that occur in the renal tubules.
GFR is used as an indicator of overall kidney function
renal clearance rate can provide more detailed information about how efficiently the kidneys handle specific substances
